Re: Improving the isolationtester: fewer failures, less delay - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Improving the isolationtester: fewer failures, less delay
Date
Msg-id 795616.1623872876@sss.pgh.pa.us
Whole thread Raw
In response to Re: Improving the isolationtester: fewer failures, less delay  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
Andres Freund <andres@anarazel.de> writes:
> [ assorted review comments ]

Here's a v3 responding to your comments, plus some other cleanup:

* don't use C99-style declarations-in-for, to ease planned backpatch

* make use of (*) annotation in multiple-cic.spec, to get rid of
the need for a variant expected-file for it

            regards, tom lane

diff --git a/contrib/test_decoding/expected/concurrent_ddl_dml.out
b/contrib/test_decoding/expected/concurrent_ddl_dml.out
index 1f9e7661b7..53578c8ed6 100644
--- a/contrib/test_decoding/expected/concurrent_ddl_dml.out
+++ b/contrib/test_decoding/expected/concurrent_ddl_dml.out
@@ -257,7 +257,7 @@ step s1_insert_tbl2: INSERT INTO tbl2 (val1, val2) VALUES (1, 1);
 step s2_alter_tbl1_boolean: ALTER TABLE tbl1 ALTER COLUMN val2 TYPE boolean; <waiting ...>
 step s1_commit: COMMIT;
 step s2_alter_tbl1_boolean: <... completed>
-error in steps s1_commit s2_alter_tbl1_boolean: ERROR:  column "val2" cannot be cast automatically to type boolean
+ERROR:  column "val2" cannot be cast automatically to type boolean
 step s2_get_changes: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'include-xids', '0',
'skip-empty-xacts','1'); 
 data

diff --git a/src/test/isolation/README b/src/test/isolation/README
index 6ae7152325..9d568e5354 100644
--- a/src/test/isolation/README
+++ b/src/test/isolation/README
@@ -57,11 +57,16 @@ Test specification
 ==================

 Each isolation test is defined by a specification file, stored in the specs
-subdirectory. A test specification consists of four parts, in this order:
+subdirectory.  A test specification defines some SQL "steps", groups them
+into "sessions" (where all the steps of one session will be run in the
+same backend), and specifies the "permutations" or orderings of the steps
+that are to be run.
+
+A test specification consists of four parts, in this order:

 setup { <SQL> }

-  The given SQL block is executed once, in one session only, before running
+  The given SQL block is executed once (per permutation) before running
   the test.  Create any test tables or other required objects here.  This
   part is optional.  Multiple setup blocks are allowed if needed; each is
   run separately, in the given order.  (The reason for allowing multiple
@@ -81,8 +86,8 @@ session "<name>"
   session is executed in its own connection. A session part consists
   of three parts: setup, teardown and one or more "steps". The per-session
   setup and teardown parts have the same syntax as the per-test setup and
-  teardown described above, but they are executed in each session. The
-  setup part typically contains a "BEGIN" command to begin a transaction.
+  teardown described above, but they are executed in each session. The setup
+  part might, for example, contain a "BEGIN" command to begin a transaction.

   Each step has the syntax

@@ -101,7 +106,8 @@ permutation "<step name>" ...
   order).  Note that the list of steps in a manually specified
   "permutation" line doesn't actually have to be a permutation of the
   available steps; it could for instance repeat some steps more than once,
-  or leave others out.
+  or leave others out.  Also, each step name can be annotated with some
+  parenthesized markers, which are described below.

 Lines beginning with a # are considered comments.

@@ -110,7 +116,8 @@ specified in the spec file, or automatically generated), the isolation
 tester runs the main setup part, then per-session setup parts, then
 the selected session steps, then per-session teardown, then the main
 teardown script.  Each selected step is sent to the connection associated
-with its session.
+with its session.  The main setup and teardown scripts are run in a
+separate "control" session.


 Support for blocking commands
@@ -129,3 +136,69 @@ tests take a very long time to run, and they serve no useful testing purpose.
 Note that isolationtester recognizes that a command has blocked by looking
 to see if it is shown as waiting in the pg_locks view; therefore, only
 blocks on heavyweight locks will be detected.
+
+
+Dealing with race conditions
+============================
+
+In some cases, the isolationtester's output for a test script may vary
+due to timing issues.  One way to deal with that is to create variant
+expected-files, which follow the usual PG convention that variants for
+foo.spec are named foo_1.out, foo_2.out, etc.  However, this method is
+discouraged since the extra files are a nuisance for maintenance.
+Instead, it's usually possible to stabilize the test output by applying
+special markers to some of the step names listed in a permutation line.
+
+The general form of a permutation entry is
+
+    <step name> [ ( <marker> [ , <marker> ... ] ) ]
+
+where each marker defines a "blocking condition".  The step will not be
+reported as completed before all the blocking conditions are satisfied.
+The possible markers are:
+
+    *
+    <other step name>
+    <other step name> notices <n>
+
+An asterisk marker, such as mystep(*), forces the isolationtester to
+report the step as "waiting" as soon as it's been launched, regardless of
+whether it would have been detected as waiting later.  This is useful for
+stabilizing cases that are sometimes reported as waiting and other times
+reported as immediately completing, depending on the relative speeds of
+the step and the isolationtester's status-monitoring queries.
+
+A marker consisting solely of a step name indicates that this step may
+not be reported as completing until that other step has completed.
+This allows stabilizing cases where two queries might be seen to complete
+in either order.  Note that this step can be *launched* before the other
+step has completed.  (If the other step is used more than once in the
+current permutation, this step cannot complete while any of those
+instances is active.)
+
+A marker of the form "<other step name> notices <n>" (where <n> is a
+positive integer) indicates that this step may not be reported as
+completing until the other step's session has returned at least <n>
+NOTICE messages, counting from when this step is launched.  This is useful
+for stabilizing cases where a step can return NOTICE messages before it
+actually completes, and those messages must be synchronized with the
+completions of other steps.
+
+Notice that these markers can only delay reporting of the completion
+of a step, not the launch of a step.  The isolationtester will launch
+the next step in a permutation as soon as (A) all prior steps of the
+same session are done, and (B) the immediately preceding step in the
+permutation is done or deemed blocked.  For this purpose, "deemed
+blocked" means that it has been seen to be waiting on a database lock,
+or that it is complete but the report of its completion is delayed by
+one of these markers.
+
+In some cases it is important not to launch a step until after the
+completion of a step in another session that could have been deemed
+blocked.  An example is that if step s1 in session A is issuing a
+cancel for step s2 in session B, we'd better not launch B's next step
+till we're sure s1 is done.  If s1 is blockable, trouble could ensue.
+The best way to prevent that is to create an empty step in session A
+and run it, without any markers, just before the next session B step.
+The empty step cannot be launched until s1 is done, and in turn the
+next session B step cannot be launched until the empty step finishes.
diff --git a/src/test/isolation/expected/alter-table-3.out b/src/test/isolation/expected/alter-table-3.out
index b4f3b5a86d..aad8372069 100644
--- a/src/test/isolation/expected/alter-table-3.out
+++ b/src/test/isolation/expected/alter-table-3.out
@@ -54,7 +54,7 @@ i
 step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s1a s1b s2a s1c s1d s2b s2c s2d
@@ -97,7 +97,7 @@ i
 step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s1a s1b s2a s2b s1c s1d s2c s2d
@@ -126,7 +126,7 @@ step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s1a s1b s2a s2b s2c s1c s1d s2d
@@ -141,7 +141,7 @@ step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s1a s2a s1b s1c s1d s2b s2c s2d
@@ -184,7 +184,7 @@ i
 step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s1a s2a s1b s2b s1c s1d s2c s2d
@@ -213,7 +213,7 @@ step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s1a s2a s1b s2b s2c s1c s1d s2d
@@ -228,7 +228,7 @@ step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s1a s2a s2b s1b s1c s1d s2c s2d
@@ -257,7 +257,7 @@ step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s1a s2a s2b s1b s2c s1c s1d s2d
@@ -272,7 +272,7 @@ step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s1a s2a s2b s2c s1b s1c s1d s2d
@@ -371,7 +371,7 @@ i
 step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s2a s1a s1b s2b s1c s1d s2c s2d
@@ -400,7 +400,7 @@ step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s2a s1a s1b s2b s2c s1c s1d s2d
@@ -415,7 +415,7 @@ step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s2a s1a s2b s1b s1c s1d s2c s2d
@@ -444,7 +444,7 @@ step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s2a s1a s2b s1b s2c s1c s1d s2d
@@ -459,7 +459,7 @@ step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s2a s1a s2b s2c s1b s1c s1d s2d
@@ -544,7 +544,7 @@ step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s2a s2b s1a s1b s2c s1c s1d s2d
@@ -559,7 +559,7 @@ step s2c: INSERT INTO a VALUES (0); <waiting ...>
 step s1c: ALTER TABLE a ENABLE TRIGGER t;
 step s1d: COMMIT;
 step s2c: <... completed>
-error in steps s1d s2c: ERROR:  duplicate key value violates unique constraint "a_pkey"
+ERROR:  duplicate key value violates unique constraint "a_pkey"
 step s2d: COMMIT;

 starting permutation: s2a s2b s1a s2c s1b s1c s1d s2d
diff --git a/src/test/isolation/expected/alter-table-4.out b/src/test/isolation/expected/alter-table-4.out
index d2dac0be09..1009844f06 100644
--- a/src/test/isolation/expected/alter-table-4.out
+++ b/src/test/isolation/expected/alter-table-4.out
@@ -50,7 +50,7 @@ step s1modc1a: ALTER TABLE c1 ALTER COLUMN a TYPE float;
 step s2sel: SELECT SUM(a) FROM p; <waiting ...>
 step s1c: COMMIT;
 step s2sel: <... completed>
-error in steps s1c s2sel: ERROR:  attribute "a" of relation "c1" does not match parent's type
+ERROR:  attribute "a" of relation "c1" does not match parent's type
 step s2sel: SELECT SUM(a) FROM p;
 sum

diff --git a/src/test/isolation/expected/deadlock-hard.out b/src/test/isolation/expected/deadlock-hard.out
index b4ce01962d..460653f2b8 100644
--- a/src/test/isolation/expected/deadlock-hard.out
+++ b/src/test/isolation/expected/deadlock-hard.out
@@ -18,8 +18,8 @@ step s6a7: LOCK TABLE a7; <waiting ...>
 step s7a8: LOCK TABLE a8; <waiting ...>
 step s8a1: LOCK TABLE a1; <waiting ...>
 step s8a1: <... completed>
+ERROR:  deadlock detected
 step s7a8: <... completed>
-error in steps s8a1 s7a8: ERROR:  deadlock detected
 step s8c: COMMIT;
 step s7c: COMMIT;
 step s6a7: <... completed>
diff --git a/src/test/isolation/expected/deadlock-simple.out b/src/test/isolation/expected/deadlock-simple.out
index e0d2c4ef12..8be1538dd5 100644
--- a/src/test/isolation/expected/deadlock-simple.out
+++ b/src/test/isolation/expected/deadlock-simple.out
@@ -5,7 +5,7 @@ step s1as: LOCK TABLE a1 IN ACCESS SHARE MODE;
 step s2as: LOCK TABLE a1 IN ACCESS SHARE MODE;
 step s1ae: LOCK TABLE a1 IN ACCESS EXCLUSIVE MODE; <waiting ...>
 step s2ae: LOCK TABLE a1 IN ACCESS EXCLUSIVE MODE;
+ERROR:  deadlock detected
 step s1ae: <... completed>
-error in steps s2ae s1ae: ERROR:  deadlock detected
 step s1c: COMMIT;
 step s2c: COMMIT;
diff --git a/src/test/isolation/expected/detach-partition-concurrently-3.out
b/src/test/isolation/expected/detach-partition-concurrently-3.out
index 96ee090d53..7ac22a6b15 100644
--- a/src/test/isolation/expected/detach-partition-concurrently-3.out
+++ b/src/test/isolation/expected/detach-partition-concurrently-3.out
@@ -1,6 +1,6 @@
 Parsed test spec with 2 sessions

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s1describe s1alter
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s1describe s1alter
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -8,13 +8,12 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s1describe: SELECT 'd3_listp' AS root, * FROM pg_partition_tree('d3_listp')
                       UNION ALL SELECT 'd3_listp1', * FROM pg_partition_tree('d3_listp1');
@@ -26,7 +25,7 @@ d3_listp1      d3_listp1                     t              0
 step s1alter: ALTER TABLE d3_listp1 ALTER a DROP NOT NULL;
 ERROR:  cannot alter partition "d3_listp1" with an incomplete detach

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1insert s1c
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1insert s1c
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -34,18 +33,17 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1insert: INSERT INTO d3_listp VALUES (1);
 ERROR:  no partition of relation "d3_listp" found for row
 step s1c: COMMIT;

-starting permutation: s2snitch s1brr s1s s2detach s1cancel s2noop s1insert s1c s1spart
+starting permutation: s2snitch s1brr s1s s2detach s1cancel s1insert s1c s1spart
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1brr: BEGIN ISOLATION LEVEL REPEATABLE READ;
 step s1s: SELECT * FROM d3_listp;
@@ -53,13 +51,12 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1insert: INSERT INTO d3_listp VALUES (1);
 step s1c: COMMIT;
 step s1spart: SELECT * FROM d3_listp1;
@@ -68,7 +65,7 @@ a
 1
 1

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s1insertpart
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s1insertpart
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -76,17 +73,16 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s1insertpart: INSERT INTO d3_listp1 VALUES (1);

-starting permutation: s2snitch s1b s1s s2detach2 s1cancel s2noop s1c s1brr s1insert s1s s1insert s1c
+starting permutation: s2snitch s1b s1s s2detach2 s1cancel s1c s1brr s1insert s1s s1insert s1c
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -94,13 +90,12 @@ a

 1
 step s2detach2: ALTER TABLE d3_listp DETACH PARTITION d3_listp2 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach2: <... completed>
-error in steps s1cancel s2detach2: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s1brr: BEGIN ISOLATION LEVEL REPEATABLE READ;
 step s1insert: INSERT INTO d3_listp VALUES (1);
@@ -112,7 +107,7 @@ a
 step s1insert: INSERT INTO d3_listp VALUES (1);
 step s1c: COMMIT;

-starting permutation: s2snitch s1b s1s s2detach2 s1cancel s2noop s1c s1brr s1s s1insert s1s s1c
+starting permutation: s2snitch s1b s1s s2detach2 s1cancel s1c s1brr s1s s1insert s1s s1c
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -120,13 +115,12 @@ a

 1
 step s2detach2: ALTER TABLE d3_listp DETACH PARTITION d3_listp2 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach2: <... completed>
-error in steps s1cancel s2detach2: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s1brr: BEGIN ISOLATION LEVEL REPEATABLE READ;
 step s1s: SELECT * FROM d3_listp;
@@ -141,7 +135,7 @@ a
 1
 step s1c: COMMIT;

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s1drop s1list
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s1drop s1list
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -149,13 +143,12 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s1drop: DROP TABLE d3_listp;
 step s1list: SELECT relname FROM pg_catalog.pg_class
@@ -163,7 +156,7 @@ step s1list: SELECT relname FROM pg_catalog.pg_class
 relname


-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s1trunc s1spart
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s1trunc s1spart
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -171,13 +164,12 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s1trunc: TRUNCATE TABLE d3_listp;
 step s1spart: SELECT * FROM d3_listp1;
@@ -185,7 +177,7 @@ a

 1

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s2detach2 s1c
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1noop s2detach2 s1c
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -193,18 +185,18 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
+step s1noop:
 step s2detach2: ALTER TABLE d3_listp DETACH PARTITION d3_listp2 CONCURRENTLY;
 ERROR:  partition "d3_listp1" already pending detach in partitioned table "public.d3_listp"
 step s1c: COMMIT;

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s2detachfinal s1c s2detach2
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1noop s2detachfinal s1c s2detach2
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -212,19 +204,19 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
+step s1noop:
 step s2detachfinal: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 FINALIZE; <waiting ...>
 step s1c: COMMIT;
 step s2detachfinal: <... completed>
 step s2detach2: ALTER TABLE d3_listp DETACH PARTITION d3_listp2 CONCURRENTLY;

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s1droppart s2detach2
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s1droppart s2detach2
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -232,18 +224,17 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s1droppart: DROP TABLE d3_listp1;
 step s2detach2: ALTER TABLE d3_listp DETACH PARTITION d3_listp2 CONCURRENTLY;

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s2begin s2drop s1s s2commit
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s2begin s2drop s1s s2commit
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -251,13 +242,12 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s2begin: BEGIN;
 step s2drop: DROP TABLE d3_listp1;
@@ -267,7 +257,7 @@ step s1s: <... completed>
 a


-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s1b s1spart s2detachfinal s1c
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s1b s1spart s2detachfinal s1c
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -275,13 +265,12 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s1b: BEGIN;
 step s1spart: SELECT * FROM d3_listp1;
@@ -292,7 +281,7 @@ step s2detachfinal: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 FINALIZE; <w
 step s1c: COMMIT;
 step s2detachfinal: <... completed>

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s1b s1s s2detachfinal s1c
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s1b s1s s2detachfinal s1c
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -300,13 +289,12 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -315,7 +303,7 @@ a
 step s2detachfinal: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 FINALIZE;
 step s1c: COMMIT;

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s1b s1spart s2detachfinal s1c
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s1b s1spart s2detachfinal s1c
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -323,13 +311,12 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s1b: BEGIN;
 step s1spart: SELECT * FROM d3_listp1;
@@ -340,7 +327,7 @@ step s2detachfinal: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 FINALIZE; <w
 step s1c: COMMIT;
 step s2detachfinal: <... completed>

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s2begin s2detachfinal s2commit
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s2begin s2detachfinal s2commit
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -348,19 +335,18 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s2begin: BEGIN;
 step s2detachfinal: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 FINALIZE;
 step s2commit: COMMIT;

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s2begin s2detachfinal s1spart s2commit
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s2begin s2detachfinal s1spart s2commit
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -368,13 +354,12 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s2begin: BEGIN;
 step s2detachfinal: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 FINALIZE;
@@ -385,7 +370,7 @@ a

 1

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1c s2begin s2detachfinal s1insertpart s2commit
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1c s2begin s2detachfinal s1insertpart s2commit
 step s2snitch: INSERT INTO d3_pid SELECT pg_backend_pid();
 step s1b: BEGIN;
 step s1s: SELECT * FROM d3_listp;
@@ -393,13 +378,12 @@ a

 1
 step s2detach: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; <waiting ...>
-step s1cancel: SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: SELECT pg_cancel_backend(pid) FROM d3_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: COMMIT;
 step s2begin: BEGIN;
 step s2detachfinal: ALTER TABLE d3_listp DETACH PARTITION d3_listp1 FINALIZE;
diff --git a/src/test/isolation/expected/detach-partition-concurrently-4.out
b/src/test/isolation/expected/detach-partition-concurrently-4.out
index e5dc40d076..d49736a17d 100644
--- a/src/test/isolation/expected/detach-partition-concurrently-4.out
+++ b/src/test/isolation/expected/detach-partition-concurrently-4.out
@@ -1,6 +1,6 @@
 Parsed test spec with 3 sessions

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s1insert s1c
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1insert s1c
 step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1b: begin;
 step s1s: select * from d4_primary;
@@ -9,13 +9,12 @@ a
 1
 2
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid), pg_sleep(0.1) from d4_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1insert: insert into d4_fk values (1);
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s1c: commit;
@@ -30,11 +29,11 @@ a
 2
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
 step s1insert: insert into d4_fk values (1);
+ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s2detach: <... completed>
-error in steps s1insert s2detach: ERROR:  insert or update on table "d4_fk" violates foreign key constraint
"d4_fk_a_fkey"
 step s1c: commit;

-starting permutation: s2snitch s1brr s1s s2detach s1cancel s2noop s1insert s1c
+starting permutation: s2snitch s1brr s1s s2detach s1cancel s1insert s1c
 step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1brr: begin isolation level repeatable read;
 step s1s: select * from d4_primary;
@@ -43,13 +42,12 @@ a
 1
 2
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid), pg_sleep(0.1) from d4_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1insert: insert into d4_fk values (1);
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s1c: commit;
@@ -64,22 +62,21 @@ a
 2
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
 step s1insert: insert into d4_fk values (1);
+ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s2detach: <... completed>
-error in steps s1insert s2detach: ERROR:  insert or update on table "d4_fk" violates foreign key constraint
"d4_fk_a_fkey"
 step s1c: commit;

-starting permutation: s2snitch s1b s1declare s2detach s1cancel s2noop s1fetchall s1insert s1c
+starting permutation: s2snitch s1b s1declare s2detach s1cancel s1fetchall s1insert s1c
 step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1b: begin;
 step s1declare: declare f cursor for select * from d4_primary;
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid), pg_sleep(0.1) from d4_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1fetchall: fetch all from f;
 a

@@ -100,22 +97,21 @@ a
 1
 2
 step s1insert: insert into d4_fk values (1);
+ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s2detach: <... completed>
-error in steps s1insert s2detach: ERROR:  insert or update on table "d4_fk" violates foreign key constraint
"d4_fk_a_fkey"
 step s1c: commit;

-starting permutation: s2snitch s1b s1declare s2detach s1cancel s2noop s1svpt s1insert s1rollback s1fetchall s1c
+starting permutation: s2snitch s1b s1declare s2detach s1cancel s1svpt s1insert s1rollback s1fetchall s1c
 step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1b: begin;
 step s1declare: declare f cursor for select * from d4_primary;
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid), pg_sleep(0.1) from d4_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1svpt: savepoint f;
 step s1insert: insert into d4_fk values (1);
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
@@ -144,16 +140,15 @@ a
 step s1c: commit;
 step s2detach: <... completed>

-starting permutation: s2snitch s1b s2detach s1declare s1cancel s2noop s1fetchall s1insert s1c
+starting permutation: s2snitch s1b s2detach s1declare s1cancel s1fetchall s1insert s1c
 step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1b: begin;
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently;
 step s1declare: declare f cursor for select * from d4_primary;
-step s1cancel: select pg_cancel_backend(pid), pg_sleep(0.1) from d4_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+pg_cancel_backend

-t
-step s2noop: UNLISTEN noop;
+t
 step s1fetchall: fetch all from f;
 a

@@ -175,16 +170,15 @@ step s1insert: insert into d4_fk values (1);
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s1c: commit;

-starting permutation: s2snitch s1b s2detach s1declare s1cancel s2noop s1svpt s1insert s1rollback s1fetchall s1c
+starting permutation: s2snitch s1b s2detach s1declare s1cancel s1svpt s1insert s1rollback s1fetchall s1c
 step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1b: begin;
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently;
 step s1declare: declare f cursor for select * from d4_primary;
-step s1cancel: select pg_cancel_backend(pid), pg_sleep(0.1) from d4_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+pg_cancel_backend

-t
-step s2noop: UNLISTEN noop;
+t
 step s1svpt: savepoint f;
 step s1insert: insert into d4_fk values (1);
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
@@ -210,7 +204,7 @@ a
 2
 step s1c: commit;

-starting permutation: s2snitch s1brr s1declare2 s1fetchone s2detach s1cancel s2noop s1updcur s1c
+starting permutation: s2snitch s1brr s1declare2 s1fetchone s2detach s1cancel s1updcur s1c
 step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1brr: begin isolation level repeatable read;
 step s1declare2: declare f cursor for select * from d4_fk where a = 2;
@@ -219,13 +213,12 @@ a

 2
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid), pg_sleep(0.1) from d4_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1updcur: update d4_fk set a = 1 where current of f;
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s1c: commit;
@@ -240,8 +233,8 @@ a
 2
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
 step s1updcur: update d4_fk set a = 1 where current of f;
+ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s2detach: <... completed>
-error in steps s1updcur s2detach: ERROR:  insert or update on table "d4_fk" violates foreign key constraint
"d4_fk_a_fkey"
 step s1c: commit;

 starting permutation: s2snitch s1brr s1declare2 s1fetchone s1updcur s2detach s1c
@@ -256,7 +249,7 @@ step s1updcur: update d4_fk set a = 1 where current of f;
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
 step s1c: commit;
 step s2detach: <... completed>
-error in steps s1c s2detach: ERROR:  removing partition "d4_primary1" violates foreign key constraint "d4_fk_a_fkey1"
+ERROR:  removing partition "d4_primary1" violates foreign key constraint "d4_fk_a_fkey1"

 starting permutation: s2snitch s1b s1s s2detach s3insert s1c
 step s2snitch: insert into d4_pid select pg_backend_pid();
@@ -272,7 +265,7 @@ ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk
 step s1c: commit;
 step s2detach: <... completed>

-starting permutation: s2snitch s1b s1s s2detach s3brr s3insert s3commit s1cancel s2noop s1c
+starting permutation: s2snitch s1b s1s s2detach s3brr s3insert s3commit s1cancel s1c
 step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1b: begin;
 step s1s: select * from d4_primary;
@@ -285,13 +278,12 @@ step s3brr: begin isolation level repeatable read;
 step s3insert: insert into d4_fk values (1);
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s3commit: commit;
-step s1cancel: select pg_cancel_backend(pid), pg_sleep(0.1) from d4_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
 step s1c: commit;

 starting permutation: s2snitch s1b s1s s2detach s3brr s3insert s3commit s1c
@@ -310,7 +302,7 @@ step s3commit: commit;
 step s1c: commit;
 step s2detach: <... completed>

-starting permutation: s2snitch s1brr s1s s2detach s1cancel s2noop s3vacfreeze s1s s1insert s1c
+starting permutation: s2snitch s1brr s1s s2detach s1cancel s1noop s3vacfreeze s1s s1insert s1c
 step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1brr: begin isolation level repeatable read;
 step s1s: select * from d4_primary;
@@ -319,13 +311,13 @@ a
 1
 2
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid), pg_sleep(0.1) from d4_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
+step s1noop:
 step s3vacfreeze: vacuum freeze pg_catalog.pg_inherits;
 step s1s: select * from d4_primary;
 a
@@ -336,7 +328,7 @@ step s1insert: insert into d4_fk values (1);
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s1c: commit;

-starting permutation: s2snitch s1b s1s s2detach s1cancel s2noop s3vacfreeze s1s s1insert s1c
+starting permutation: s2snitch s1b s1s s2detach s1cancel s1noop s3vacfreeze s1s s1insert s1c
 step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1b: begin;
 step s1s: select * from d4_primary;
@@ -345,13 +337,13 @@ a
 1
 2
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid), pg_sleep(0.1) from d4_pid;
-pg_cancel_backendpg_sleep
+step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+pg_cancel_backend

-t
+t
 step s2detach: <... completed>
-error in steps s1cancel s2detach: ERROR:  canceling statement due to user request
-step s2noop: UNLISTEN noop;
+ERROR:  canceling statement due to user request
+step s1noop:
 step s3vacfreeze: vacuum freeze pg_catalog.pg_inherits;
 step s1s: select * from d4_primary;
 a
diff --git a/src/test/isolation/expected/eval-plan-qual-trigger.out
b/src/test/isolation/expected/eval-plan-qual-trigger.out
index f0d975ce0c..833834afaa 100644
--- a/src/test/isolation/expected/eval-plan-qual-trigger.out
+++ b/src/test/isolation/expected/eval-plan-qual-trigger.out
@@ -1,3 +1,9 @@
+unused step name: s2_r
+unused step name: s3_b_rc
+unused step name: s3_c
+unused step name: s3_del_a
+unused step name: s3_r
+unused step name: s3_upd_a_data
 Parsed test spec with 4 sessions

 starting permutation: s1_trig_rep_b_u s1_trig_rep_a_u s1_ins_a s1_ins_b s1_b_rc s2_b_rc s1_upd_a_data s1_c
s2_upd_a_datas2_c s0_rep 
@@ -609,7 +615,7 @@ s2: NOTICE:  trigger: name rep_b_i; when: BEFORE; lev: ROWs; op: INSERT; old: <N
 step s2_ins_a: INSERT INTO trigtest VALUES ('key-a', 'val-a-s2') RETURNING *; <waiting ...>
 step s1_c: COMMIT;
 step s2_ins_a: <... completed>
-error in steps s1_c s2_ins_a: ERROR:  duplicate key value violates unique constraint "trigtest_pkey"
+ERROR:  duplicate key value violates unique constraint "trigtest_pkey"
 step s2_c: COMMIT;
 step s0_rep: SELECT * FROM trigtest ORDER BY key, data
 key            data
@@ -2023,7 +2029,7 @@ step s2_upd_a_data:
  <waiting ...>
 step s1_c: COMMIT;
 step s2_upd_a_data: <... completed>
-error in steps s1_c s2_upd_a_data: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2_c: COMMIT;
 step s0_rep: SELECT * FROM trigtest ORDER BY key, data
 key            data
@@ -2136,7 +2142,7 @@ step s2_upd_a_data:
  <waiting ...>
 step s1_c: COMMIT;
 step s2_upd_a_data: <... completed>
-error in steps s1_c s2_upd_a_data: ERROR:  could not serialize access due to concurrent delete
+ERROR:  could not serialize access due to concurrent delete
 step s2_c: COMMIT;
 step s0_rep: SELECT * FROM trigtest ORDER BY key, data
 key            data
@@ -2202,9 +2208,3 @@ key            data

 key-a          val-a-s1-ups2
 key-b          val-b-s1
-unused step name: s2_r
-unused step name: s3_b_rc
-unused step name: s3_c
-unused step name: s3_del_a
-unused step name: s3_r
-unused step name: s3_upd_a_data
diff --git a/src/test/isolation/expected/eval-plan-qual.out b/src/test/isolation/expected/eval-plan-qual.out
index 3e55a55c63..df8fa8b0a5 100644
--- a/src/test/isolation/expected/eval-plan-qual.out
+++ b/src/test/isolation/expected/eval-plan-qual.out
@@ -551,7 +551,7 @@ balance
 step updwctefail: WITH doup AS (UPDATE accounts SET balance = balance + 1100 WHERE accountid = 'checking' RETURNING *,
update_checking(999))UPDATE accounts a SET balance = doup.balance + 100 FROM doup RETURNING *; <waiting ...> 
 step c1: COMMIT;
 step updwctefail: <... completed>
-error in steps c1 updwctefail: ERROR:  tuple to be updated was already modified by an operation triggered by the
currentcommand 
+ERROR:  tuple to be updated was already modified by an operation triggered by the current command
 step c2: COMMIT;
 step read: SELECT * FROM accounts ORDER BY accountid;
 accountid      balance
@@ -584,7 +584,7 @@ balance
 step delwctefail: WITH doup AS (UPDATE accounts SET balance = balance + 1100 WHERE accountid = 'checking' RETURNING *,
update_checking(999))DELETE FROM accounts a USING doup RETURNING *; <waiting ...> 
 step c1: COMMIT;
 step delwctefail: <... completed>
-error in steps c1 delwctefail: ERROR:  tuple to be deleted was already modified by an operation triggered by the
currentcommand 
+ERROR:  tuple to be deleted was already modified by an operation triggered by the current command
 step c2: COMMIT;
 step read: SELECT * FROM accounts ORDER BY accountid;
 accountid      balance
@@ -931,7 +931,7 @@ step complexpartupdate_route_err1:
  <waiting ...>
 step c1: COMMIT;
 step complexpartupdate_route_err1: <... completed>
-error in steps c1 complexpartupdate_route_err1: ERROR:  tuple to be locked was already moved to another partition due
toconcurrent update 
+ERROR:  tuple to be locked was already moved to another partition due to concurrent update
 step c2: COMMIT;

 starting permutation: simplepartupdate_noroute complexpartupdate_route c1 c2
diff --git a/src/test/isolation/expected/fk-deadlock2_1.out b/src/test/isolation/expected/fk-deadlock2_1.out
index 382734811c..e1d8c692cb 100644
--- a/src/test/isolation/expected/fk-deadlock2_1.out
+++ b/src/test/isolation/expected/fk-deadlock2_1.out
@@ -14,7 +14,7 @@ step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 step s2u1: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s1c: COMMIT;
 step s2u1: <... completed>
-error in steps s1c s2u1: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 ERROR:  current transaction is aborted, commands ignored until end of transaction block
 step s2c: COMMIT;
@@ -26,7 +26,7 @@ step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s2u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 step s2c: COMMIT;
 step s1u2: <... completed>
-error in steps s2c s1u2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s1u1 s2u1 s2u2 s1u2 s2c s1c
@@ -36,7 +36,7 @@ step s2u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s2c: COMMIT;
 step s1u2: <... completed>
-error in steps s2c s1u2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s1u1 s2u1 s2u2 s2c s1u2 s1c
@@ -55,7 +55,7 @@ step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s2u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 step s2c: COMMIT;
 step s1u2: <... completed>
-error in steps s2c s1u2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s2u1 s1u1 s2u2 s1u2 s2c s1c
@@ -65,7 +65,7 @@ step s2u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s2c: COMMIT;
 step s1u2: <... completed>
-error in steps s2c s1u2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s2u1 s1u1 s2u2 s2c s1u2 s1c
@@ -84,7 +84,7 @@ step s1u1: UPDATE A SET Col1 = 1 WHERE AID = 1;
 step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s2c: COMMIT;
 step s1u2: <... completed>
-error in steps s2c s1u2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s2u1 s2u2 s1u1 s2c s1u2 s1c
diff --git a/src/test/isolation/expected/fk-deadlock2_2.out b/src/test/isolation/expected/fk-deadlock2_2.out
index b6be4b9892..9787370913 100644
--- a/src/test/isolation/expected/fk-deadlock2_2.out
+++ b/src/test/isolation/expected/fk-deadlock2_2.out
@@ -14,7 +14,7 @@ step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 step s2u1: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s1c: COMMIT;
 step s2u1: <... completed>
-error in steps s1c s2u1: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 ERROR:  current transaction is aborted, commands ignored until end of transaction block
 step s2c: COMMIT;
@@ -26,7 +26,7 @@ step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s2u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 step s2c: COMMIT;
 step s1u2: <... completed>
-error in steps s2c s1u2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s1u1 s2u1 s2u2 s1u2 s2c s1c
@@ -36,7 +36,7 @@ step s2u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s2c: COMMIT;
 step s1u2: <... completed>
-error in steps s2c s1u2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s1u1 s2u1 s2u2 s2c s1u2 s1c
@@ -55,7 +55,7 @@ step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s2u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 step s2c: COMMIT;
 step s1u2: <... completed>
-error in steps s2c s1u2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s2u1 s1u1 s2u2 s1u2 s2c s1c
@@ -65,7 +65,7 @@ step s2u2: UPDATE B SET Col2 = 1 WHERE BID = 2;
 step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s2c: COMMIT;
 step s1u2: <... completed>
-error in steps s2c s1u2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s2u1 s1u1 s2u2 s2c s1u2 s1c
@@ -84,7 +84,7 @@ step s1u1: UPDATE A SET Col1 = 1 WHERE AID = 1;
 step s1u2: UPDATE B SET Col2 = 1 WHERE BID = 2; <waiting ...>
 step s2c: COMMIT;
 step s1u2: <... completed>
-error in steps s2c s1u2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s2u1 s2u2 s1u1 s2c s1u2 s1c
diff --git a/src/test/isolation/expected/fk-deadlock_1.out b/src/test/isolation/expected/fk-deadlock_1.out
index 0dae5d3a5a..c951692744 100644
--- a/src/test/isolation/expected/fk-deadlock_1.out
+++ b/src/test/isolation/expected/fk-deadlock_1.out
@@ -24,7 +24,7 @@ step s2i: INSERT INTO child VALUES (2, 1);
 step s2u: UPDATE parent SET aux = 'baz'; <waiting ...>
 step s1c: COMMIT;
 step s2u: <... completed>
-error in steps s1c s2u: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;

 starting permutation: s1i s2i s1u s1c s2u s2c
@@ -43,7 +43,7 @@ step s1u: UPDATE parent SET aux = 'bar';
 step s2u: UPDATE parent SET aux = 'baz'; <waiting ...>
 step s1c: COMMIT;
 step s2u: <... completed>
-error in steps s1c s2u: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;

 starting permutation: s1i s2i s2u s1u s2c s1c
@@ -53,7 +53,7 @@ step s2u: UPDATE parent SET aux = 'baz';
 step s1u: UPDATE parent SET aux = 'bar'; <waiting ...>
 step s2c: COMMIT;
 step s1u: <... completed>
-error in steps s2c s1u: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s1i s2i s2u s2c s1u s1c
@@ -81,7 +81,7 @@ step s1u: UPDATE parent SET aux = 'bar';
 step s2u: UPDATE parent SET aux = 'baz'; <waiting ...>
 step s1c: COMMIT;
 step s2u: <... completed>
-error in steps s1c s2u: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;

 starting permutation: s2i s1i s2u s1u s2c s1c
@@ -91,7 +91,7 @@ step s2u: UPDATE parent SET aux = 'baz';
 step s1u: UPDATE parent SET aux = 'bar'; <waiting ...>
 step s2c: COMMIT;
 step s1u: <... completed>
-error in steps s2c s1u: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s2i s1i s2u s2c s1u s1c
@@ -110,7 +110,7 @@ step s1i: INSERT INTO child VALUES (1, 1);
 step s1u: UPDATE parent SET aux = 'bar'; <waiting ...>
 step s2c: COMMIT;
 step s1u: <... completed>
-error in steps s2c s1u: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1c: COMMIT;

 starting permutation: s2i s2u s1i s2c s1u s1c
diff --git a/src/test/isolation/expected/fk-partitioned-1.out b/src/test/isolation/expected/fk-partitioned-1.out
index aea2b6d56b..45f2f8cba7 100644
--- a/src/test/isolation/expected/fk-partitioned-1.out
+++ b/src/test/isolation/expected/fk-partitioned-1.out
@@ -25,7 +25,7 @@ step s2b: begin;
 step s2a: alter table pfk attach partition pfk1 for values in (1); <waiting ...>
 step s1c: commit;
 step s2a: <... completed>
-error in steps s1c s2a: ERROR:  insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey"
+ERROR:  insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey"
 step s2c: commit;

 starting permutation: s1b s2b s1d s1c s2a s2c
@@ -44,7 +44,7 @@ step s1d: delete from ppk1 where a = 1;
 step s2a: alter table pfk attach partition pfk1 for values in (1); <waiting ...>
 step s1c: commit;
 step s2a: <... completed>
-error in steps s1c s2a: ERROR:  insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey"
+ERROR:  insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey"
 step s2c: commit;

 starting permutation: s1b s2b s2a s1d s2c s1c
@@ -54,7 +54,7 @@ step s2a: alter table pfk attach partition pfk1 for values in (1);
 step s1d: delete from ppk1 where a = 1; <waiting ...>
 step s2c: commit;
 step s1d: <... completed>
-error in steps s2c s1d: ERROR:  update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on
table"pfk" 
+ERROR:  update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on table "pfk"
 step s1c: commit;

 starting permutation: s1b s2b s2a s2c s1d s1c
@@ -82,7 +82,7 @@ step s1d: delete from ppk1 where a = 1;
 step s2a: alter table pfk attach partition pfk1 for values in (1); <waiting ...>
 step s1c: commit;
 step s2a: <... completed>
-error in steps s1c s2a: ERROR:  insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey"
+ERROR:  insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey"
 step s2c: commit;

 starting permutation: s2b s1b s2a s1d s2c s1c
@@ -92,7 +92,7 @@ step s2a: alter table pfk attach partition pfk1 for values in (1);
 step s1d: delete from ppk1 where a = 1; <waiting ...>
 step s2c: commit;
 step s1d: <... completed>
-error in steps s2c s1d: ERROR:  update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on
table"pfk" 
+ERROR:  update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on table "pfk"
 step s1c: commit;

 starting permutation: s2b s1b s2a s2c s1d s1c
@@ -111,7 +111,7 @@ step s1b: begin;
 step s1d: delete from ppk1 where a = 1; <waiting ...>
 step s2c: commit;
 step s1d: <... completed>
-error in steps s2c s1d: ERROR:  update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on
table"pfk" 
+ERROR:  update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on table "pfk"
 step s1c: commit;

 starting permutation: s2b s2a s1b s2c s1d s1c
diff --git a/src/test/isolation/expected/fk-partitioned-2.out b/src/test/isolation/expected/fk-partitioned-2.out
index 722b615c6e..278bec4fdf 100644
--- a/src/test/isolation/expected/fk-partitioned-2.out
+++ b/src/test/isolation/expected/fk-partitioned-2.out
@@ -7,7 +7,7 @@ step s2b: begin;
 step s2i: insert into pfk values (1); <waiting ...>
 step s1c: commit;
 step s2i: <... completed>
-error in steps s1c s2i: ERROR:  insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey"
+ERROR:  insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey"
 step s2c: commit;

 starting permutation: s1b s1d s2bs s2i s1c s2c
@@ -20,7 +20,7 @@ step s2bs: begin isolation level serializable; select 1;
 step s2i: insert into pfk values (1); <waiting ...>
 step s1c: commit;
 step s2i: <... completed>
-error in steps s1c s2i: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: commit;

 starting permutation: s1b s2b s1d s2i s1c s2c
@@ -30,7 +30,7 @@ step s1d: delete from ppk where a = 1;
 step s2i: insert into pfk values (1); <waiting ...>
 step s1c: commit;
 step s2i: <... completed>
-error in steps s1c s2i: ERROR:  insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey"
+ERROR:  insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey"
 step s2c: commit;

 starting permutation: s1b s2bs s1d s2i s1c s2c
@@ -43,7 +43,7 @@ step s1d: delete from ppk where a = 1;
 step s2i: insert into pfk values (1); <waiting ...>
 step s1c: commit;
 step s2i: <... completed>
-error in steps s1c s2i: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: commit;

 starting permutation: s1b s2b s2i s1d s2c s1c
@@ -53,7 +53,7 @@ step s2i: insert into pfk values (1);
 step s1d: delete from ppk where a = 1; <waiting ...>
 step s2c: commit;
 step s1d: <... completed>
-error in steps s2c s1d: ERROR:  update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on
table"pfk" 
+ERROR:  update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on table "pfk"
 step s1c: commit;

 starting permutation: s1b s2bs s2i s1d s2c s1c
@@ -66,5 +66,5 @@ step s2i: insert into pfk values (1);
 step s1d: delete from ppk where a = 1; <waiting ...>
 step s2c: commit;
 step s1d: <... completed>
-error in steps s2c s1d: ERROR:  update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on
table"pfk" 
+ERROR:  update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on table "pfk"
 step s1c: commit;
diff --git a/src/test/isolation/expected/insert-conflict-do-nothing-2.out
b/src/test/isolation/expected/insert-conflict-do-nothing-2.out
index 2332f96978..c90002fd02 100644
--- a/src/test/isolation/expected/insert-conflict-do-nothing-2.out
+++ b/src/test/isolation/expected/insert-conflict-do-nothing-2.out
@@ -31,7 +31,7 @@ step donothing1: INSERT INTO ints(key, val) VALUES(1, 'donothing1') ON CONFLICT
 step donothing2: INSERT INTO ints(key, val) VALUES(1, 'donothing2'), (1, 'donothing3') ON CONFLICT DO NOTHING;
<waiting...> 
 step c1: COMMIT;
 step donothing2: <... completed>
-error in steps c1 donothing2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step c2: COMMIT;
 step show: SELECT * FROM ints;
 key            val
@@ -45,7 +45,7 @@ step donothing2: INSERT INTO ints(key, val) VALUES(1, 'donothing2'), (1, 'donoth
 step donothing1: INSERT INTO ints(key, val) VALUES(1, 'donothing1') ON CONFLICT DO NOTHING; <waiting ...>
 step c2: COMMIT;
 step donothing1: <... completed>
-error in steps c2 donothing1: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step c1: COMMIT;
 step show: SELECT * FROM ints;
 key            val
@@ -83,7 +83,7 @@ step donothing1: INSERT INTO ints(key, val) VALUES(1, 'donothing1') ON CONFLICT
 step donothing2: INSERT INTO ints(key, val) VALUES(1, 'donothing2'), (1, 'donothing3') ON CONFLICT DO NOTHING;
<waiting...> 
 step c1: COMMIT;
 step donothing2: <... completed>
-error in steps c1 donothing2: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step c2: COMMIT;
 step show: SELECT * FROM ints;
 key            val
@@ -97,7 +97,7 @@ step donothing2: INSERT INTO ints(key, val) VALUES(1, 'donothing2'), (1, 'donoth
 step donothing1: INSERT INTO ints(key, val) VALUES(1, 'donothing1') ON CONFLICT DO NOTHING; <waiting ...>
 step c2: COMMIT;
 step donothing1: <... completed>
-error in steps c2 donothing1: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step c1: COMMIT;
 step show: SELECT * FROM ints;
 key            val
diff --git a/src/test/isolation/expected/insert-conflict-specconflict.out
b/src/test/isolation/expected/insert-conflict-specconflict.out
index ae361fbd03..8d319296dd 100644
--- a/src/test/isolation/expected/insert-conflict-specconflict.out
+++ b/src/test/isolation/expected/insert-conflict-specconflict.out
@@ -284,7 +284,7 @@ key            data

 k1             inserted s1 with conflict update s2

-starting permutation: s1_create_non_unique_index s1_confirm_index_order controller_locks controller_show s2_begin
s1_upserts2_upsert controller_show controller_unlock_1_1 controller_unlock_2_1 controller_unlock_1_3
controller_unlock_2_3controller_show controller_lock_2_4 controller_unlock_2_2 controller_show controller_unlock_1_2
controller_print_speculative_lockscontroller_unlock_2_4 controller_print_speculative_locks s2_commit controller_show
controller_print_speculative_locks
+starting permutation: s1_create_non_unique_index s1_confirm_index_order controller_locks controller_show s2_begin
s1_upserts2_upsert controller_show controller_unlock_1_1 controller_unlock_2_1 controller_unlock_1_3
controller_unlock_2_3controller_show controller_lock_2_4 controller_unlock_2_2 controller_show controller_unlock_1_2
controller_print_speculative_lockscontroller_unlock_2_4 s2_noop controller_print_speculative_locks s2_commit s1_noop
controller_showcontroller_print_speculative_locks 
 step s1_create_non_unique_index: CREATE INDEX upserttest_key_idx ON upserttest((blurt_and_lock_4(key)));
 step s1_confirm_index_order: SELECT 'upserttest_key_uniq_idx'::regclass::int8 < 'upserttest_key_idx'::regclass::int8;
 ?column?
@@ -380,6 +380,7 @@ t
 s1: NOTICE:  blurt_and_lock_123() called for k1 in session 1
 s1: NOTICE:  acquiring advisory lock on 2
 step s2_upsert: <... completed>
+step s2_noop:
 step controller_print_speculative_locks:
     SELECT pa.application_name, locktype, mode, granted
     FROM pg_locks pl JOIN pg_stat_activity pa USING (pid)
@@ -398,6 +399,7 @@ step s2_commit: COMMIT;
 s1: NOTICE:  blurt_and_lock_123() called for k1 in session 1
 s1: NOTICE:  acquiring advisory lock on 2
 step s1_upsert: <... completed>
+step s1_noop:
 step controller_show: SELECT * FROM upserttest;
 key            data

diff --git a/src/test/isolation/expected/lock-committed-keyupdate.out
b/src/test/isolation/expected/lock-committed-keyupdate.out
index 69cdbfba0a..2f13a19b9a 100644
--- a/src/test/isolation/expected/lock-committed-keyupdate.out
+++ b/src/test/isolation/expected/lock-committed-keyupdate.out
@@ -192,7 +192,7 @@ pg_advisory_unlock

 t
 step s2l: <... completed>
-error in steps s1ul s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 pg_advisory_unlock_all

@@ -216,7 +216,7 @@ pg_advisory_unlock

 t
 step s2l: <... completed>
-error in steps s1ul s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 pg_advisory_unlock_all

@@ -240,7 +240,7 @@ t
 step s2l: SELECT * FROM lcku_table WHERE pg_advisory_lock(578902068) IS NOT NULL FOR KEY SHARE; <waiting ...>
 step s1c: COMMIT;
 step s2l: <... completed>
-error in steps s1c s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 pg_advisory_unlock_all

@@ -269,7 +269,7 @@ pg_advisory_unlock

 t
 step s2l: <... completed>
-error in steps s1ul s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 pg_advisory_unlock_all

@@ -298,7 +298,7 @@ pg_advisory_unlock

 t
 step s2l: <... completed>
-error in steps s1ul s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 pg_advisory_unlock_all

@@ -322,7 +322,7 @@ t
 step s2l: SELECT * FROM lcku_table WHERE pg_advisory_lock(578902068) IS NOT NULL FOR KEY SHARE; <waiting ...>
 step s1c: COMMIT;
 step s2l: <... completed>
-error in steps s1c s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1hint: SELECT * FROM lcku_table;
 id             value

@@ -351,7 +351,7 @@ pg_advisory_unlock

 t
 step s2l: <... completed>
-error in steps s1ul s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 pg_advisory_unlock_all

@@ -375,7 +375,7 @@ pg_advisory_unlock

 t
 step s2l: <... completed>
-error in steps s1ul s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 pg_advisory_unlock_all

@@ -399,7 +399,7 @@ t
 step s2l: SELECT * FROM lcku_table WHERE pg_advisory_lock(578902068) IS NOT NULL FOR KEY SHARE; <waiting ...>
 step s1c: COMMIT;
 step s2l: <... completed>
-error in steps s1c s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 pg_advisory_unlock_all

@@ -428,7 +428,7 @@ pg_advisory_unlock

 t
 step s2l: <... completed>
-error in steps s1ul s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 pg_advisory_unlock_all

@@ -457,7 +457,7 @@ pg_advisory_unlock

 t
 step s2l: <... completed>
-error in steps s1ul s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 pg_advisory_unlock_all

@@ -481,7 +481,7 @@ t
 step s2l: SELECT * FROM lcku_table WHERE pg_advisory_lock(578902068) IS NOT NULL FOR KEY SHARE; <waiting ...>
 step s1c: COMMIT;
 step s2l: <... completed>
-error in steps s1c s2l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1hint: SELECT * FROM lcku_table;
 id             value

diff --git a/src/test/isolation/expected/lock-update-delete_1.out
b/src/test/isolation/expected/lock-update-delete_1.out
index f1c1c7026f..77adde718d 100644
--- a/src/test/isolation/expected/lock-update-delete_1.out
+++ b/src/test/isolation/expected/lock-update-delete_1.out
@@ -14,7 +14,7 @@ pg_advisory_unlock
 t
 step s2c: COMMIT;
 step s1l: <... completed>
-error in steps s2c s1l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update

 starting permutation: s2b s1l s2u s2_blocker2 s2_unlock s2c
 pg_advisory_lock
@@ -30,7 +30,7 @@ pg_advisory_unlock
 t
 step s2c: COMMIT;
 step s1l: <... completed>
-error in steps s2c s1l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update

 starting permutation: s2b s1l s2u s2_blocker3 s2_unlock s2c
 pg_advisory_lock
@@ -118,7 +118,7 @@ pg_advisory_unlock

 t
 step s1l: <... completed>
-error in steps s2_unlock s1l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update

 starting permutation: s2b s1l s2u s2_blocker2 s2c s2_unlock
 pg_advisory_lock
@@ -134,7 +134,7 @@ pg_advisory_unlock

 t
 step s1l: <... completed>
-error in steps s2_unlock s1l: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update

 starting permutation: s2b s1l s2u s2_blocker3 s2c s2_unlock
 pg_advisory_lock
diff --git a/src/test/isolation/expected/multiple-cic.out b/src/test/isolation/expected/multiple-cic.out
index 2bf8fe365e..e41e04a480 100644
--- a/src/test/isolation/expected/multiple-cic.out
+++ b/src/test/isolation/expected/multiple-cic.out
@@ -12,8 +12,9 @@ step s1i:
 step s2i:
         CREATE INDEX CONCURRENTLY mcic_two_pkey ON mcic_two (id)
         WHERE unlck();
-
+ <waiting ...>
 step s1i: <... completed>
+step s2i: <... completed>
 unlck

 t
diff --git a/src/test/isolation/expected/multiple-cic_1.out b/src/test/isolation/expected/multiple-cic_1.out
deleted file mode 100644
index e41e04a480..0000000000
--- a/src/test/isolation/expected/multiple-cic_1.out
+++ /dev/null
@@ -1,20 +0,0 @@
-Parsed test spec with 2 sessions
-
-starting permutation: s2l s1i s2i
-step s2l: SELECT pg_advisory_lock(281457);
-pg_advisory_lock
-
-
-step s1i:
-        CREATE INDEX CONCURRENTLY mcic_one_pkey ON mcic_one (id)
-        WHERE lck_shr(281457);
- <waiting ...>
-step s2i:
-        CREATE INDEX CONCURRENTLY mcic_two_pkey ON mcic_two (id)
-        WHERE unlck();
- <waiting ...>
-step s1i: <... completed>
-step s2i: <... completed>
-unlck
-
-t
diff --git a/src/test/isolation/expected/multixact-no-forget_1.out
b/src/test/isolation/expected/multixact-no-forget_1.out
index 1c37afef1a..205a40099c 100644
--- a/src/test/isolation/expected/multixact-no-forget_1.out
+++ b/src/test/isolation/expected/multixact-no-forget_1.out
@@ -83,7 +83,7 @@ step s1_commit: COMMIT;
 step s3_fornokeyupd: SELECT * FROM dont_forget FOR NO KEY UPDATE; <waiting ...>
 step s2_commit: COMMIT;
 step s3_fornokeyupd: <... completed>
-error in steps s2_commit s3_fornokeyupd: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update

 starting permutation: s1_lock s2_update s2_abort s3_forupd s1_commit
 step s1_lock: SELECT * FROM dont_forget FOR KEY SHARE;
@@ -123,4 +123,4 @@ step s1_commit: COMMIT;
 step s3_forupd: SELECT * FROM dont_forget FOR UPDATE; <waiting ...>
 step s2_commit: COMMIT;
 step s3_forupd: <... completed>
-error in steps s2_commit s3_forupd: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
diff --git a/src/test/isolation/expected/nowait-4.out b/src/test/isolation/expected/nowait-4.out
index 26f59bef94..c1db66581b 100644
--- a/src/test/isolation/expected/nowait-4.out
+++ b/src/test/isolation/expected/nowait-4.out
@@ -14,6 +14,6 @@ pg_advisory_unlock

 t
 step s1a: <... completed>
-error in steps s2e s1a: ERROR:  could not obtain lock on row in relation "foo"
+ERROR:  could not obtain lock on row in relation "foo"
 step s1b: COMMIT;
 step s2f: COMMIT;
diff --git a/src/test/isolation/expected/nowait-4_1.out b/src/test/isolation/expected/nowait-4_1.out
index 959d51baae..5fa6b3453a 100644
--- a/src/test/isolation/expected/nowait-4_1.out
+++ b/src/test/isolation/expected/nowait-4_1.out
@@ -14,6 +14,6 @@ pg_advisory_unlock

 t
 step s1a: <... completed>
-error in steps s2e s1a: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1b: COMMIT;
 step s2f: COMMIT;
diff --git a/src/test/isolation/expected/nowait-5.out b/src/test/isolation/expected/nowait-5.out
index c88aae5ef6..2682ea1ab3 100644
--- a/src/test/isolation/expected/nowait-5.out
+++ b/src/test/isolation/expected/nowait-5.out
@@ -34,4 +34,4 @@ pg_advisory_unlock

 t
 step sl1_exec: <... completed>
-error in steps upd_releaselock sl1_exec: ERROR:  could not obtain lock on row in relation "test_nowait"
+ERROR:  could not obtain lock on row in relation "test_nowait"
diff --git a/src/test/isolation/expected/partition-concurrent-attach.out
b/src/test/isolation/expected/partition-concurrent-attach.out
index 17fac39989..4986ee25e8 100644
--- a/src/test/isolation/expected/partition-concurrent-attach.out
+++ b/src/test/isolation/expected/partition-concurrent-attach.out
@@ -7,7 +7,7 @@ step s2b: begin;
 step s2i: insert into tpart values (110,'xxx'), (120, 'yyy'), (150, 'zzz'); <waiting ...>
 step s1c: commit;
 step s2i: <... completed>
-error in steps s1c s2i: ERROR:  new row for relation "tpart_default" violates partition constraint
+ERROR:  new row for relation "tpart_default" violates partition constraint
 step s2c: commit;
 step s2s: select tableoid::regclass, * from tpart;
 tableoid       i              j
@@ -23,7 +23,7 @@ step s2b: begin;
 step s2i2: insert into tpart_default (i, j) values (110, 'xxx'), (120, 'yyy'), (150, 'zzz'); <waiting ...>
 step s1c: commit;
 step s2i2: <... completed>
-error in steps s1c s2i2: ERROR:  new row for relation "tpart_default" violates partition constraint
+ERROR:  new row for relation "tpart_default" violates partition constraint
 step s2c: commit;
 step s2s: select tableoid::regclass, * from tpart;
 tableoid       i              j
@@ -39,7 +39,7 @@ step s2i: insert into tpart values (110,'xxx'), (120, 'yyy'), (150, 'zzz');
 step s1a: alter table tpart attach partition tpart_2 for values from (100) to (200); <waiting ...>
 step s2c: commit;
 step s1a: <... completed>
-error in steps s2c s1a: ERROR:  updated partition constraint for default partition "tpart_default_default" would be
violatedby some row 
+ERROR:  updated partition constraint for default partition "tpart_default_default" would be violated by some row
 step s1c: commit;
 step s2s: select tableoid::regclass, * from tpart;
 tableoid       i              j
diff --git a/src/test/isolation/expected/partition-key-update-1.out
b/src/test/isolation/expected/partition-key-update-1.out
index c1a9c56ae4..7dee144f2f 100644
--- a/src/test/isolation/expected/partition-key-update-1.out
+++ b/src/test/isolation/expected/partition-key-update-1.out
@@ -15,7 +15,7 @@ step s1u: UPDATE foo SET a=2 WHERE a=1;
 step s2d: DELETE FROM foo WHERE a=1; <waiting ...>
 step s1c: COMMIT;
 step s2d: <... completed>
-error in steps s1c s2d: ERROR:  tuple to be locked was already moved to another partition due to concurrent update
+ERROR:  tuple to be locked was already moved to another partition due to concurrent update
 step s2c: COMMIT;

 starting permutation: s1b s2b s1u s2u s1c s2c
@@ -25,7 +25,7 @@ step s1u: UPDATE foo SET a=2 WHERE a=1;
 step s2u: UPDATE foo SET b='EFG' WHERE a=1; <waiting ...>
 step s1c: COMMIT;
 step s2u: <... completed>
-error in steps s1c s2u: ERROR:  tuple to be locked was already moved to another partition due to concurrent update
+ERROR:  tuple to be locked was already moved to another partition due to concurrent update
 step s2c: COMMIT;

 starting permutation: s1b s2b s2d s1u s2c s1c
@@ -52,7 +52,7 @@ step s1u2: UPDATE footrg SET b='EFG' WHERE a=1;
 step s2u2: UPDATE footrg SET b='XYZ' WHERE a=1; <waiting ...>
 step s1c: COMMIT;
 step s2u2: <... completed>
-error in steps s1c s2u2: ERROR:  tuple to be locked was already moved to another partition due to concurrent update
+ERROR:  tuple to be locked was already moved to another partition due to concurrent update
 step s2c: COMMIT;

 starting permutation: s1b s2b s2u2 s1u2 s2c s1c
@@ -62,7 +62,7 @@ step s2u2: UPDATE footrg SET b='XYZ' WHERE a=1;
 step s1u2: UPDATE footrg SET b='EFG' WHERE a=1; <waiting ...>
 step s2c: COMMIT;
 step s1u2: <... completed>
-error in steps s2c s1u2: ERROR:  tuple to be locked was already moved to another partition due to concurrent update
+ERROR:  tuple to be locked was already moved to another partition due to concurrent update
 step s1c: COMMIT;

 starting permutation: s1b s2b s1u3pc s2i s1c s2c
@@ -72,7 +72,7 @@ step s1u3pc: UPDATE foo_range_parted SET a=11 WHERE a=7;
 step s2i: INSERT INTO bar VALUES(7); <waiting ...>
 step s1c: COMMIT;
 step s2i: <... completed>
-error in steps s1c s2i: ERROR:  tuple to be locked was already moved to another partition due to concurrent update
+ERROR:  tuple to be locked was already moved to another partition due to concurrent update
 step s2c: COMMIT;

 starting permutation: s1b s2b s1u3pc s2i s1r s2c
@@ -92,7 +92,7 @@ step s1u3pc: UPDATE foo_range_parted SET a=11 WHERE a=7;
 step s2i: INSERT INTO bar VALUES(7); <waiting ...>
 step s1c: COMMIT;
 step s2i: <... completed>
-error in steps s1c s2i: ERROR:  tuple to be locked was already moved to another partition due to concurrent update
+ERROR:  tuple to be locked was already moved to another partition due to concurrent update
 step s2c: COMMIT;

 starting permutation: s1b s2b s1u3npc s1u3pc s2i s1r s2c
@@ -114,7 +114,7 @@ step s1u3pc: UPDATE foo_range_parted SET a=11 WHERE a=7;
 step s2i: INSERT INTO bar VALUES(7); <waiting ...>
 step s1c: COMMIT;
 step s2i: <... completed>
-error in steps s1c s2i: ERROR:  tuple to be locked was already moved to another partition due to concurrent update
+ERROR:  tuple to be locked was already moved to another partition due to concurrent update
 step s2c: COMMIT;

 starting permutation: s1b s2b s1u3npc s1u3pc s1u3pc s2i s1r s2c
diff --git a/src/test/isolation/expected/partition-key-update-3.out
b/src/test/isolation/expected/partition-key-update-3.out
index 42dfe64ad3..a06af2d719 100644
--- a/src/test/isolation/expected/partition-key-update-3.out
+++ b/src/test/isolation/expected/partition-key-update-3.out
@@ -23,7 +23,7 @@ step s1u: UPDATE foo SET a=2, b=b || ' -> moved by session-1' WHERE a=1;
 step s3donothing: INSERT INTO foo VALUES(2, 'session-3 donothing'), (2, 'session-3 donothing2') ON CONFLICT DO
NOTHING;<waiting ...> 
 step s1c: COMMIT;
 step s3donothing: <... completed>
-error in steps s1c s3donothing: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s3c: COMMIT;
 step s2donothing: INSERT INTO foo VALUES(1, 'session-2 donothing') ON CONFLICT DO NOTHING;
 step s2c: COMMIT;
@@ -42,7 +42,7 @@ step s3donothing: INSERT INTO foo VALUES(2, 'session-3 donothing'), (2, 'session
 step s1c: COMMIT;
 step s2donothing: <... completed>
 step s3donothing: <... completed>
-error in steps s1c s2donothing s3donothing: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 step s3c: COMMIT;
 step s2select: SELECT * FROM foo ORDER BY a;
@@ -59,8 +59,8 @@ step s3donothing: INSERT INTO foo VALUES(2, 'session-3 donothing'), (2, 'session
 step s2donothing: INSERT INTO foo VALUES(1, 'session-2 donothing') ON CONFLICT DO NOTHING; <waiting ...>
 step s1c: COMMIT;
 step s3donothing: <... completed>
+ERROR:  could not serialize access due to concurrent update
 step s2donothing: <... completed>
-error in steps s1c s3donothing s2donothing: ERROR:  could not serialize access due to concurrent update
 step s3c: COMMIT;
 step s2c: COMMIT;
 step s2select: SELECT * FROM foo ORDER BY a;
@@ -92,7 +92,7 @@ step s1u: UPDATE foo SET a=2, b=b || ' -> moved by session-1' WHERE a=1;
 step s3donothing: INSERT INTO foo VALUES(2, 'session-3 donothing'), (2, 'session-3 donothing2') ON CONFLICT DO
NOTHING;<waiting ...> 
 step s1c: COMMIT;
 step s3donothing: <... completed>
-error in steps s1c s3donothing: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s3c: COMMIT;
 step s2donothing: INSERT INTO foo VALUES(1, 'session-2 donothing') ON CONFLICT DO NOTHING;
 step s2c: COMMIT;
@@ -111,7 +111,7 @@ step s3donothing: INSERT INTO foo VALUES(2, 'session-3 donothing'), (2, 'session
 step s1c: COMMIT;
 step s2donothing: <... completed>
 step s3donothing: <... completed>
-error in steps s1c s2donothing s3donothing: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s2c: COMMIT;
 step s3c: COMMIT;
 step s2select: SELECT * FROM foo ORDER BY a;
@@ -128,8 +128,8 @@ step s3donothing: INSERT INTO foo VALUES(2, 'session-3 donothing'), (2, 'session
 step s2donothing: INSERT INTO foo VALUES(1, 'session-2 donothing') ON CONFLICT DO NOTHING; <waiting ...>
 step s1c: COMMIT;
 step s3donothing: <... completed>
+ERROR:  could not serialize access due to concurrent update
 step s2donothing: <... completed>
-error in steps s1c s3donothing s2donothing: ERROR:  could not serialize access due to concurrent update
 step s3c: COMMIT;
 step s2c: COMMIT;
 step s2select: SELECT * FROM foo ORDER BY a;
diff --git a/src/test/isolation/expected/propagate-lock-delete.out
b/src/test/isolation/expected/propagate-lock-delete.out
index b668b895f1..222b945fee 100644
--- a/src/test/isolation/expected/propagate-lock-delete.out
+++ b/src/test/isolation/expected/propagate-lock-delete.out
@@ -11,7 +11,7 @@ step s3d: DELETE FROM parent; <waiting ...>
 step s1c: COMMIT;
 step s2c: COMMIT;
 step s3d: <... completed>
-error in steps s2c s3d: ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on
table"child" 
+ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on table "child"
 step s3c: COMMIT;

 starting permutation: s1b s1l s2b s2l s3b s3u s3svu s3d s1c s2c s3c
@@ -26,7 +26,7 @@ step s3d: DELETE FROM parent; <waiting ...>
 step s1c: COMMIT;
 step s2c: COMMIT;
 step s3d: <... completed>
-error in steps s2c s3d: ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on
table"child" 
+ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on table "child"
 step s3c: COMMIT;

 starting permutation: s1b s1l s2b s2l s3b s3u2 s3d s1c s2c s3c
@@ -40,7 +40,7 @@ step s3d: DELETE FROM parent; <waiting ...>
 step s1c: COMMIT;
 step s2c: COMMIT;
 step s3d: <... completed>
-error in steps s2c s3d: ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on
table"child" 
+ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on table "child"
 step s3c: COMMIT;

 starting permutation: s1b s1l s2b s2l s3b s3u2 s3svu s3d s1c s2c s3c
@@ -55,7 +55,7 @@ step s3d: DELETE FROM parent; <waiting ...>
 step s1c: COMMIT;
 step s2c: COMMIT;
 step s3d: <... completed>
-error in steps s2c s3d: ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on
table"child" 
+ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on table "child"
 step s3c: COMMIT;

 starting permutation: s1b s1l s3b s3u s3d s1c s3c
@@ -66,7 +66,7 @@ step s3u: UPDATE parent SET c=lower(c);
 step s3d: DELETE FROM parent; <waiting ...>
 step s1c: COMMIT;
 step s3d: <... completed>
-error in steps s1c s3d: ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on
table"child" 
+ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on table "child"
 step s3c: COMMIT;

 starting permutation: s1b s1l s3b s3u s3svu s3d s1c s3c
@@ -78,7 +78,7 @@ step s3svu: SAVEPOINT f; UPDATE parent SET c = 'bbb'; ROLLBACK TO f;
 step s3d: DELETE FROM parent; <waiting ...>
 step s1c: COMMIT;
 step s3d: <... completed>
-error in steps s1c s3d: ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on
table"child" 
+ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on table "child"
 step s3c: COMMIT;

 starting permutation: s1b s1l s3b s3u2 s3d s1c s3c
@@ -89,7 +89,7 @@ step s3u2: UPDATE parent SET i = i;
 step s3d: DELETE FROM parent; <waiting ...>
 step s1c: COMMIT;
 step s3d: <... completed>
-error in steps s1c s3d: ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on
table"child" 
+ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on table "child"
 step s3c: COMMIT;

 starting permutation: s1b s1l s3b s3u2 s3svu s3d s1c s3c
@@ -101,5 +101,5 @@ step s3svu: SAVEPOINT f; UPDATE parent SET c = 'bbb'; ROLLBACK TO f;
 step s3d: DELETE FROM parent; <waiting ...>
 step s1c: COMMIT;
 step s3d: <... completed>
-error in steps s1c s3d: ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on
table"child" 
+ERROR:  update or delete on table "parent" violates foreign key constraint "child_i_fkey" on table "child"
 step s3c: COMMIT;
diff --git a/src/test/isolation/expected/read-write-unique-2.out b/src/test/isolation/expected/read-write-unique-2.out
index 5e27f0adfd..a36ae3a97c 100644
--- a/src/test/isolation/expected/read-write-unique-2.out
+++ b/src/test/isolation/expected/read-write-unique-2.out
@@ -11,7 +11,7 @@ step w1: INSERT INTO test VALUES (42);
 step w2: INSERT INTO test VALUES (42); <waiting ...>
 step c1: COMMIT;
 step w2: <... completed>
-error in steps c1 w2: ERROR:  could not serialize access due to read/write dependencies among transactions
+ERROR:  could not serialize access due to read/write dependencies among transactions
 step c2: COMMIT;

 starting permutation: r1 w1 c1 r2 w2 c2
diff --git a/src/test/isolation/expected/read-write-unique-3.out b/src/test/isolation/expected/read-write-unique-3.out
index edd3558930..5b308de981 100644
--- a/src/test/isolation/expected/read-write-unique-3.out
+++ b/src/test/isolation/expected/read-write-unique-3.out
@@ -8,5 +8,5 @@ insert_unique
 step rw2: SELECT insert_unique(1, '2'); <waiting ...>
 step c1: COMMIT;
 step rw2: <... completed>
-error in steps c1 rw2: ERROR:  could not serialize access due to read/write dependencies among transactions
+ERROR:  could not serialize access due to read/write dependencies among transactions
 step c2: COMMIT;
diff --git a/src/test/isolation/expected/read-write-unique-4.out b/src/test/isolation/expected/read-write-unique-4.out
index 64ff157513..5f36837702 100644
--- a/src/test/isolation/expected/read-write-unique-4.out
+++ b/src/test/isolation/expected/read-write-unique-4.out
@@ -13,7 +13,7 @@ step w1: INSERT INTO invoice VALUES (2016, 3);
 step w2: INSERT INTO invoice VALUES (2016, 3); <waiting ...>
 step c1: COMMIT;
 step w2: <... completed>
-error in steps c1 w2: ERROR:  could not serialize access due to read/write dependencies among transactions
+ERROR:  could not serialize access due to read/write dependencies among transactions
 step c2: COMMIT;

 starting permutation: r1 w1 w2 c1 c2
@@ -25,7 +25,7 @@ step w1: INSERT INTO invoice VALUES (2016, 3);
 step w2: INSERT INTO invoice VALUES (2016, 3); <waiting ...>
 step c1: COMMIT;
 step w2: <... completed>
-error in steps c1 w2: ERROR:  duplicate key value violates unique constraint "invoice_pkey"
+ERROR:  duplicate key value violates unique constraint "invoice_pkey"
 step c2: COMMIT;

 starting permutation: r2 w1 w2 c1 c2
@@ -37,5 +37,5 @@ step w1: INSERT INTO invoice VALUES (2016, 3);
 step w2: INSERT INTO invoice VALUES (2016, 3); <waiting ...>
 step c1: COMMIT;
 step w2: <... completed>
-error in steps c1 w2: ERROR:  duplicate key value violates unique constraint "invoice_pkey"
+ERROR:  duplicate key value violates unique constraint "invoice_pkey"
 step c2: COMMIT;
diff --git a/src/test/isolation/expected/read-write-unique.out b/src/test/isolation/expected/read-write-unique.out
index fb32ec3261..b438674230 100644
--- a/src/test/isolation/expected/read-write-unique.out
+++ b/src/test/isolation/expected/read-write-unique.out
@@ -11,7 +11,7 @@ step w1: INSERT INTO test VALUES (42);
 step w2: INSERT INTO test VALUES (42); <waiting ...>
 step c1: COMMIT;
 step w2: <... completed>
-error in steps c1 w2: ERROR:  could not serialize access due to read/write dependencies among transactions
+ERROR:  could not serialize access due to read/write dependencies among transactions
 step c2: COMMIT;

 starting permutation: r1 w1 c1 r2 w2 c2
diff --git a/src/test/isolation/expected/sequence-ddl.out b/src/test/isolation/expected/sequence-ddl.out
index 6766c0aff6..5cf08d7f3c 100644
--- a/src/test/isolation/expected/sequence-ddl.out
+++ b/src/test/isolation/expected/sequence-ddl.out
@@ -11,7 +11,7 @@ step s1alter: ALTER SEQUENCE seq1 MAXVALUE 10;
 step s2nv: SELECT nextval('seq1') FROM generate_series(1, 15); <waiting ...>
 step s1commit: COMMIT;
 step s2nv: <... completed>
-error in steps s1commit s2nv: ERROR:  nextval: reached maximum value of sequence "seq1" (10)
+ERROR:  nextval: reached maximum value of sequence "seq1" (10)

 starting permutation: s1restart s2nv s1commit
 step s1restart: ALTER SEQUENCE seq1 RESTART WITH 5;
diff --git a/src/test/isolation/expected/skip-locked-4_1.out b/src/test/isolation/expected/skip-locked-4_1.out
index 552429ae89..e7ea5d7a8d 100644
--- a/src/test/isolation/expected/skip-locked-4_1.out
+++ b/src/test/isolation/expected/skip-locked-4_1.out
@@ -14,6 +14,6 @@ pg_advisory_unlock

 t
 step s1a: <... completed>
-error in steps s2e s1a: ERROR:  could not serialize access due to concurrent update
+ERROR:  could not serialize access due to concurrent update
 step s1b: COMMIT;
 step s2f: COMMIT;
diff --git a/src/test/isolation/expected/timeouts.out b/src/test/isolation/expected/timeouts.out
index ff646279ec..d9ecdc9532 100644
--- a/src/test/isolation/expected/timeouts.out
+++ b/src/test/isolation/expected/timeouts.out
@@ -6,7 +6,7 @@ accountid      balance

 checking       600
 savings        600
-step sto: SET statement_timeout = 5000;
+step sto: SET statement_timeout = '10ms';
 step locktbl: LOCK TABLE accounts; <waiting ...>
 step locktbl: <... completed>
 ERROR:  canceling statement due to statement timeout
@@ -17,7 +17,7 @@ accountid      balance

 checking       600
 savings        600
-step lto: SET lock_timeout = 5000;
+step lto: SET lock_timeout = '10ms';
 step locktbl: LOCK TABLE accounts; <waiting ...>
 step locktbl: <... completed>
 ERROR:  canceling statement due to lock timeout
@@ -28,7 +28,7 @@ accountid      balance

 checking       600
 savings        600
-step lsto: SET lock_timeout = 5000; SET statement_timeout = 6000;
+step lsto: SET lock_timeout = '10ms'; SET statement_timeout = '10s';
 step locktbl: LOCK TABLE accounts; <waiting ...>
 step locktbl: <... completed>
 ERROR:  canceling statement due to lock timeout
@@ -39,35 +39,35 @@ accountid      balance

 checking       600
 savings        600
-step slto: SET lock_timeout = 6000; SET statement_timeout = 5000;
+step slto: SET lock_timeout = '10s'; SET statement_timeout = '10ms';
 step locktbl: LOCK TABLE accounts; <waiting ...>
 step locktbl: <... completed>
 ERROR:  canceling statement due to statement timeout

 starting permutation: wrtbl sto update
 step wrtbl: UPDATE accounts SET balance = balance + 100;
-step sto: SET statement_timeout = 5000;
+step sto: SET statement_timeout = '10ms';
 step update: DELETE FROM accounts WHERE accountid = 'checking'; <waiting ...>
 step update: <... completed>
 ERROR:  canceling statement due to statement timeout

 starting permutation: wrtbl lto update
 step wrtbl: UPDATE accounts SET balance = balance + 100;
-step lto: SET lock_timeout = 5000;
+step lto: SET lock_timeout = '10ms';
 step update: DELETE FROM accounts WHERE accountid = 'checking'; <waiting ...>
 step update: <... completed>
 ERROR:  canceling statement due to lock timeout

 starting permutation: wrtbl lsto update
 step wrtbl: UPDATE accounts SET balance = balance + 100;
-step lsto: SET lock_timeout = 5000; SET statement_timeout = 6000;
+step lsto: SET lock_timeout = '10ms'; SET statement_timeout = '10s';
 step update: DELETE FROM accounts WHERE accountid = 'checking'; <waiting ...>
 step update: <... completed>
 ERROR:  canceling statement due to lock timeout

 starting permutation: wrtbl slto update
 step wrtbl: UPDATE accounts SET balance = balance + 100;
-step slto: SET lock_timeout = 6000; SET statement_timeout = 5000;
+step slto: SET lock_timeout = '10s'; SET statement_timeout = '10ms';
 step update: DELETE FROM accounts WHERE accountid = 'checking'; <waiting ...>
 step update: <... completed>
 ERROR:  canceling statement due to statement timeout
diff --git a/src/test/isolation/expected/tuplelock-update.out b/src/test/isolation/expected/tuplelock-update.out
index ea63022e93..7bd7bbf30a 100644
--- a/src/test/isolation/expected/tuplelock-update.out
+++ b/src/test/isolation/expected/tuplelock-update.out
@@ -18,19 +18,22 @@ step s1_grablock: SELECT * FROM pktab FOR KEY SHARE;
 id             data

 1              2
-step s1_advunlock1: SELECT pg_advisory_unlock(142857);
+step s1_advunlock1: SELECT pg_advisory_unlock(142857); <waiting ...>
+step s2_update: <... completed>
+step s1_advunlock1: <... completed>
 pg_advisory_unlock

 t
-step s2_update: <... completed>
-step s1_advunlock2: SELECT pg_sleep(5), pg_advisory_unlock(285714);
-pg_sleep       pg_advisory_unlock
-
-               t
+step s1_advunlock2: SELECT pg_advisory_unlock(285714); <waiting ...>
 step s3_update: <... completed>
-step s1_advunlock3: SELECT pg_sleep(5), pg_advisory_unlock(571428);
-pg_sleep       pg_advisory_unlock
+step s1_advunlock2: <... completed>
+pg_advisory_unlock

-               t
+t
+step s1_advunlock3: SELECT pg_advisory_unlock(571428); <waiting ...>
 step s4_update: <... completed>
+step s1_advunlock3: <... completed>
+pg_advisory_unlock
+
+t
 step s1_commit: COMMIT;
diff --git a/src/test/isolation/isolationtester.c b/src/test/isolation/isolationtester.c
index 0a73d38dae..71546bf923 100644
--- a/src/test/isolation/isolationtester.c
+++ b/src/test/isolation/isolationtester.c
@@ -22,32 +22,55 @@

 /*
  * conns[0] is the global setup, teardown, and watchdog connection.  Additional
- * connections represent spec-defined sessions.  We also track the backend
- * PID, in numeric and string formats, for each connection.
+ * connections represent spec-defined sessions.
  */
-static PGconn **conns = NULL;
-static int *backend_pids = NULL;
-static const char **backend_pid_strs = NULL;
+typedef struct IsoConnInfo
+{
+    /* The libpq connection object for this connection. */
+    PGconn       *conn;
+    /* The backend PID, in numeric and string formats. */
+    int            backend_pid;
+    const char *backend_pid_str;
+    /* Name of the associated session. */
+    const char *sessionname;
+    /* Active step on this connection, or NULL if idle. */
+    PermutationStep *active_step;
+    /* Number of NOTICE messages received from connection. */
+    int            total_notices;
+} IsoConnInfo;
+
+static IsoConnInfo *conns = NULL;
 static int    nconns = 0;

+/* Flag indicating some new NOTICE has arrived */
+static bool any_new_notice = false;
+
 /* Maximum time to wait before giving up on a step (in usec) */
 static int64 max_step_wait = 300 * USECS_PER_SEC;


+static void check_testspec(TestSpec *testspec);
 static void run_testspec(TestSpec *testspec);
 static void run_all_permutations(TestSpec *testspec);
 static void run_all_permutations_recurse(TestSpec *testspec, int nsteps,
-                                         Step **steps);
+                                         PermutationStep **steps);
 static void run_named_permutations(TestSpec *testspec);
-static void run_permutation(TestSpec *testspec, int nsteps, Step **steps);
+static void run_permutation(TestSpec *testspec, int nsteps,
+                            PermutationStep **steps);

-#define STEP_NONBLOCK    0x1        /* return 0 as soon as cmd waits for a lock */
+/* Flag bits for try_complete_step(s) */
+#define STEP_NONBLOCK    0x1        /* return as soon as cmd waits for a lock */
 #define STEP_RETRY        0x2        /* this is a retry of a previously-waiting cmd */
-static bool try_complete_step(TestSpec *testspec, Step *step, int flags);
+
+static int    try_complete_steps(TestSpec *testspec, PermutationStep **waiting,
+                               int nwaiting, int flags);
+static bool try_complete_step(TestSpec *testspec, PermutationStep *pstep,
+                              int flags);

 static int    step_qsort_cmp(const void *a, const void *b);
 static int    step_bsearch_cmp(const void *a, const void *b);

+static bool step_has_blocker(PermutationStep *pstep);
 static void printResultSet(PGresult *res);
 static void isotesterNoticeProcessor(void *arg, const char *message);
 static void blackholeNoticeProcessor(void *arg, const char *message);
@@ -58,8 +81,8 @@ disconnect_atexit(void)
     int            i;

     for (i = 0; i < nconns; i++)
-        if (conns[i])
-            PQfinish(conns[i]);
+        if (conns[i].conn)
+            PQfinish(conns[i].conn);
 }

 int
@@ -68,14 +91,10 @@ main(int argc, char **argv)
     const char *conninfo;
     const char *env_wait;
     TestSpec   *testspec;
-    int            i,
-                j;
-    int            n;
     PGresult   *res;
     PQExpBufferData wait_query;
     int            opt;
-    int            nallsteps;
-    Step      **allsteps;
+    int            i;

     while ((opt = getopt(argc, argv, "V")) != -1)
     {
@@ -120,35 +139,8 @@ main(int argc, char **argv)
     spec_yyparse();
     testspec = &parseresult;

-    /* Create a lookup table of all steps. */
-    nallsteps = 0;
-    for (i = 0; i < testspec->nsessions; i++)
-        nallsteps += testspec->sessions[i]->nsteps;
-
-    allsteps = pg_malloc(nallsteps * sizeof(Step *));
-
-    n = 0;
-    for (i = 0; i < testspec->nsessions; i++)
-    {
-        for (j = 0; j < testspec->sessions[i]->nsteps; j++)
-            allsteps[n++] = testspec->sessions[i]->steps[j];
-    }
-
-    qsort(allsteps, nallsteps, sizeof(Step *), &step_qsort_cmp);
-    testspec->nallsteps = nallsteps;
-    testspec->allsteps = allsteps;
-
-    /* Verify that all step names are unique */
-    for (i = 1; i < testspec->nallsteps; i++)
-    {
-        if (strcmp(testspec->allsteps[i - 1]->name,
-                   testspec->allsteps[i]->name) == 0)
-        {
-            fprintf(stderr, "duplicate step name: %s\n",
-                    testspec->allsteps[i]->name);
-            exit(1);
-        }
-    }
+    /* Perform post-parse checking, and fill in linking fields */
+    check_testspec(testspec);

     printf("Parsed test spec with %d sessions\n", testspec->nsessions);

@@ -157,18 +149,21 @@ main(int argc, char **argv)
      * extra for lock wait detection and global work.
      */
     nconns = 1 + testspec->nsessions;
-    conns = (PGconn **) pg_malloc0(nconns * sizeof(PGconn *));
-    backend_pids = pg_malloc0(nconns * sizeof(*backend_pids));
-    backend_pid_strs = pg_malloc0(nconns * sizeof(*backend_pid_strs));
+    conns = (IsoConnInfo *) pg_malloc0(nconns * sizeof(IsoConnInfo));
     atexit(disconnect_atexit);

     for (i = 0; i < nconns; i++)
     {
-        conns[i] = PQconnectdb(conninfo);
-        if (PQstatus(conns[i]) != CONNECTION_OK)
+        if (i == 0)
+            conns[i].sessionname = "control connection";
+        else
+            conns[i].sessionname = testspec->sessions[i - 1]->name;
+
+        conns[i].conn = PQconnectdb(conninfo);
+        if (PQstatus(conns[i].conn) != CONNECTION_OK)
         {
             fprintf(stderr, "Connection %d failed: %s",
-                    i, PQerrorMessage(conns[i]));
+                    i, PQerrorMessage(conns[i].conn));
             exit(1);
         }

@@ -179,27 +174,17 @@ main(int argc, char **argv)
          * messages).
          */
         if (i != 0)
-            PQsetNoticeProcessor(conns[i],
+            PQsetNoticeProcessor(conns[i].conn,
                                  isotesterNoticeProcessor,
-                                 (void *) (testspec->sessions[i - 1]->name));
+                                 (void *) &conns[i]);
         else
-            PQsetNoticeProcessor(conns[i],
+            PQsetNoticeProcessor(conns[i].conn,
                                  blackholeNoticeProcessor,
                                  NULL);

         /* Save each connection's backend PID for subsequent use. */
-        backend_pids[i] = PQbackendPID(conns[i]);
-        backend_pid_strs[i] = psprintf("%d", backend_pids[i]);
-    }
-
-    /* Set the session index fields in steps. */
-    for (i = 0; i < testspec->nsessions; i++)
-    {
-        Session    *session = testspec->sessions[i];
-        int            stepindex;
-
-        for (stepindex = 0; stepindex < session->nsteps; stepindex++)
-            session->steps[stepindex]->session = i;
+        conns[i].backend_pid = PQbackendPID(conns[i].conn);
+        conns[i].backend_pid_str = psprintf("%d", conns[i].backend_pid);
     }

     /*
@@ -214,16 +199,16 @@ main(int argc, char **argv)
     appendPQExpBufferStr(&wait_query,
                          "SELECT pg_catalog.pg_isolation_test_session_is_blocked($1, '{");
     /* The spec syntax requires at least one session; assume that here. */
-    appendPQExpBufferStr(&wait_query, backend_pid_strs[1]);
+    appendPQExpBufferStr(&wait_query, conns[1].backend_pid_str);
     for (i = 2; i < nconns; i++)
-        appendPQExpBuffer(&wait_query, ",%s", backend_pid_strs[i]);
+        appendPQExpBuffer(&wait_query, ",%s", conns[i].backend_pid_str);
     appendPQExpBufferStr(&wait_query, "}')");

-    res = PQprepare(conns[0], PREP_WAITING, wait_query.data, 0, NULL);
+    res = PQprepare(conns[0].conn, PREP_WAITING, wait_query.data, 0, NULL);
     if (PQresultStatus(res) != PGRES_COMMAND_OK)
     {
         fprintf(stderr, "prepare of lock wait query failed: %s",
-                PQerrorMessage(conns[0]));
+                PQerrorMessage(conns[0].conn));
         exit(1);
     }
     PQclear(res);
@@ -238,6 +223,145 @@ main(int argc, char **argv)
     return 0;
 }

+/*
+ * Validity-check the test spec and fill in cross-links between nodes.
+ */
+static void
+check_testspec(TestSpec *testspec)
+{
+    int            nallsteps;
+    Step      **allsteps;
+    int            i,
+                j,
+                k;
+
+    /* Create a sorted lookup table of all steps. */
+    nallsteps = 0;
+    for (i = 0; i < testspec->nsessions; i++)
+        nallsteps += testspec->sessions[i]->nsteps;
+
+    allsteps = pg_malloc(nallsteps * sizeof(Step *));
+
+    k = 0;
+    for (i = 0; i < testspec->nsessions; i++)
+    {
+        for (j = 0; j < testspec->sessions[i]->nsteps; j++)
+            allsteps[k++] = testspec->sessions[i]->steps[j];
+    }
+
+    qsort(allsteps, nallsteps, sizeof(Step *), step_qsort_cmp);
+
+    /* Verify that all step names are unique. */
+    for (i = 1; i < nallsteps; i++)
+    {
+        if (strcmp(allsteps[i - 1]->name,
+                   allsteps[i]->name) == 0)
+        {
+            fprintf(stderr, "duplicate step name: %s\n",
+                    allsteps[i]->name);
+            exit(1);
+        }
+    }
+
+    /* Set the session index fields in steps. */
+    for (i = 0; i < testspec->nsessions; i++)
+    {
+        Session    *session = testspec->sessions[i];
+
+        for (j = 0; j < session->nsteps; j++)
+            session->steps[j]->session = i;
+    }
+
+    /*
+     * If we have manually-specified permutations, link PermutationSteps to
+     * Steps, and fill in blocker links.
+     */
+    for (i = 0; i < testspec->npermutations; i++)
+    {
+        Permutation *p = testspec->permutations[i];
+
+        for (j = 0; j < p->nsteps; j++)
+        {
+            PermutationStep *pstep = p->steps[j];
+            Step      **this = (Step **) bsearch(pstep->name,
+                                                 allsteps,
+                                                 nallsteps,
+                                                 sizeof(Step *),
+                                                 step_bsearch_cmp);
+
+            if (this == NULL)
+            {
+                fprintf(stderr, "undefined step \"%s\" specified in permutation\n",
+                        pstep->name);
+                exit(1);
+            }
+            pstep->step = *this;
+
+            /* Mark the step used, for check below */
+            pstep->step->used = true;
+        }
+
+        /*
+         * Identify any blocker steps.  We search only the current
+         * permutation, since steps not used there couldn't be concurrent.
+         * Note that it's OK to reference later permutation steps, so this
+         * can't be combined with the previous loop.
+         */
+        for (j = 0; j < p->nsteps; j++)
+        {
+            PermutationStep *pstep = p->steps[j];
+
+            for (k = 0; k < pstep->nblockers; k++)
+            {
+                PermutationStepBlocker *blocker = pstep->blockers[k];
+                int            n;
+
+                if (blocker->blocktype == PSB_ONCE)
+                    continue;    /* nothing to link to */
+
+                blocker->step = NULL;
+                for (n = 0; n < p->nsteps; n++)
+                {
+                    PermutationStep *otherp = p->steps[n];
+
+                    if (strcmp(otherp->name, blocker->stepname) == 0)
+                    {
+                        blocker->step = otherp->step;
+                        break;
+                    }
+                }
+                if (blocker->step == NULL)
+                {
+                    fprintf(stderr, "undefined blocking step \"%s\" referenced in permutation step \"%s\"\n",
+                            blocker->stepname, pstep->name);
+                    exit(1);
+                }
+                /* can't block on completion of step of own session */
+                if (blocker->step->session == pstep->step->session)
+                {
+                    fprintf(stderr, "permutation step \"%s\" cannot block on its own session\n",
+                            pstep->name);
+                    exit(1);
+                }
+            }
+        }
+    }
+
+    /*
+     * If we have manually-specified permutations, verify that all steps have
+     * been used, warning about anything defined but not used.  We can skip
+     * this when using automatically-generated permutations.
+     */
+    if (testspec->permutations)
+    {
+        for (i = 0; i < nallsteps; i++)
+        {
+            if (!allsteps[i]->used)
+                fprintf(stderr, "unused step name: %s\n", allsteps[i]->name);
+        }
+    }
+}
+
 static int *piles;

 /*
@@ -247,23 +371,10 @@ static int *piles;
 static void
 run_testspec(TestSpec *testspec)
 {
-    int            i;
-
     if (testspec->permutations)
         run_named_permutations(testspec);
     else
         run_all_permutations(testspec);
-
-    /*
-     * Verify that all steps have been used, complaining about anything
-     * defined but not used.
-     */
-    for (i = 0; i < testspec->nallsteps; i++)
-    {
-        if (!testspec->allsteps[i]->used)
-            fprintf(stderr, "unused step name: %s\n",
-                    testspec->allsteps[i]->name);
-    }
 }

 /*
@@ -274,14 +385,19 @@ run_all_permutations(TestSpec *testspec)
 {
     int            nsteps;
     int            i;
-    Step      **steps;
+    PermutationStep *steps;
+    PermutationStep **stepptrs;

     /* Count the total number of steps in all sessions */
     nsteps = 0;
     for (i = 0; i < testspec->nsessions; i++)
         nsteps += testspec->sessions[i]->nsteps;

-    steps = pg_malloc(sizeof(Step *) * nsteps);
+    /* Create PermutationStep workspace array */
+    steps = (PermutationStep *) pg_malloc0(sizeof(PermutationStep) * nsteps);
+    stepptrs = (PermutationStep **) pg_malloc(sizeof(PermutationStep *) * nsteps);
+    for (i = 0; i < nsteps; i++)
+        stepptrs[i] = steps + i;

     /*
      * To generate the permutations, we conceptually put the steps of each
@@ -296,28 +412,37 @@ run_all_permutations(TestSpec *testspec)
     for (i = 0; i < testspec->nsessions; i++)
         piles[i] = 0;

-    run_all_permutations_recurse(testspec, 0, steps);
+    run_all_permutations_recurse(testspec, 0, stepptrs);
 }

 static void
-run_all_permutations_recurse(TestSpec *testspec, int nsteps, Step **steps)
+run_all_permutations_recurse(TestSpec *testspec, int nsteps, PermutationStep **steps)
 {
     int            i;
-    int            found = 0;
+    bool        found = false;

     for (i = 0; i < testspec->nsessions; i++)
     {
         /* If there's any more steps in this pile, pick it and recurse */
         if (piles[i] < testspec->sessions[i]->nsteps)
         {
-            steps[nsteps] = testspec->sessions[i]->steps[piles[i]];
+            Step       *newstep = testspec->sessions[i]->steps[piles[i]];
+
+            /*
+             * These automatically-generated PermutationSteps never have
+             * blocker conditions.  So we need only fill these fields, relying
+             * on run_all_permutations() to have zeroed the rest:
+             */
+            steps[nsteps]->name = newstep->name;
+            steps[nsteps]->step = newstep;
+
             piles[i]++;

             run_all_permutations_recurse(testspec, nsteps + 1, steps);

             piles[i]--;

-            found = 1;
+            found = true;
         }
     }

@@ -332,38 +457,13 @@ run_all_permutations_recurse(TestSpec *testspec, int nsteps, Step **steps)
 static void
 run_named_permutations(TestSpec *testspec)
 {
-    int            i,
-                j;
+    int            i;

     for (i = 0; i < testspec->npermutations; i++)
     {
         Permutation *p = testspec->permutations[i];
-        Step      **steps;
-
-        steps = pg_malloc(p->nsteps * sizeof(Step *));
-
-        /* Find all the named steps using the lookup table */
-        for (j = 0; j < p->nsteps; j++)
-        {
-            Step      **this = (Step **) bsearch(p->stepnames[j],
-                                                 testspec->allsteps,
-                                                 testspec->nallsteps,
-                                                 sizeof(Step *),
-                                                 &step_bsearch_cmp);
-
-            if (this == NULL)
-            {
-                fprintf(stderr, "undefined step \"%s\" specified in permutation\n",
-                        p->stepnames[j]);
-                exit(1);
-            }
-            steps[j] = *this;
-        }
-
-        /* And run them */
-        run_permutation(testspec, p->nsteps, steps);

-        free(steps);
+        run_permutation(testspec, p->nsteps, p->steps);
     }
 }

@@ -385,102 +485,35 @@ step_bsearch_cmp(const void *a, const void *b)
     return strcmp(stepname, step->name);
 }

-/*
- * If a step caused an error to be reported, print it out and clear it.
- */
-static void
-report_error_message(Step *step)
-{
-    if (step->errormsg)
-    {
-        fprintf(stdout, "%s\n", step->errormsg);
-        free(step->errormsg);
-        step->errormsg = NULL;
-    }
-}
-
-/*
- * As above, but reports messages possibly emitted by multiple steps.  This is
- * useful when we have a blocked command awakened by another one; we want to
- * report all messages identically, for the case where we don't care which
- * one fails due to a timeout such as deadlock timeout.
- */
-static void
-report_multiple_error_messages(Step *step, int nextra, Step **extrastep)
-{
-    PQExpBufferData buffer;
-    int            n;
-
-    if (nextra == 0)
-    {
-        report_error_message(step);
-        return;
-    }
-
-    initPQExpBuffer(&buffer);
-    appendPQExpBufferStr(&buffer, step->name);
-
-    for (n = 0; n < nextra; ++n)
-        appendPQExpBuffer(&buffer, " %s", extrastep[n]->name);
-
-    if (step->errormsg)
-    {
-        fprintf(stdout, "error in steps %s: %s\n", buffer.data,
-                step->errormsg);
-        free(step->errormsg);
-        step->errormsg = NULL;
-    }
-
-    for (n = 0; n < nextra; ++n)
-    {
-        if (extrastep[n]->errormsg == NULL)
-            continue;
-        fprintf(stdout, "error in steps %s: %s\n",
-                buffer.data, extrastep[n]->errormsg);
-        free(extrastep[n]->errormsg);
-        extrastep[n]->errormsg = NULL;
-    }
-
-    termPQExpBuffer(&buffer);
-}
-
 /*
  * Run one permutation
  */
 static void
-run_permutation(TestSpec *testspec, int nsteps, Step **steps)
+run_permutation(TestSpec *testspec, int nsteps, PermutationStep **steps)
 {
     PGresult   *res;
     int            i;
-    int            w;
     int            nwaiting = 0;
-    int            nerrorstep = 0;
-    Step      **waiting;
-    Step      **errorstep;
+    PermutationStep **waiting;

-    waiting = pg_malloc(sizeof(Step *) * testspec->nsessions);
-    errorstep = pg_malloc(sizeof(Step *) * testspec->nsessions);
+    waiting = pg_malloc(sizeof(PermutationStep *) * testspec->nsessions);

     printf("\nstarting permutation:");
     for (i = 0; i < nsteps; i++)
-    {
-        /* Track the permutation as in-use */
-        steps[i]->used = true;
         printf(" %s", steps[i]->name);
-    }
     printf("\n");

     /* Perform setup */
     for (i = 0; i < testspec->nsetupsqls; i++)
     {
-        res = PQexec(conns[0], testspec->setupsqls[i]);
+        res = PQexec(conns[0].conn, testspec->setupsqls[i]);
         if (PQresultStatus(res) == PGRES_TUPLES_OK)
         {
             printResultSet(res);
         }
         else if (PQresultStatus(res) != PGRES_COMMAND_OK)
         {
-            fprintf(stderr, "setup failed: %s", PQerrorMessage(conns[0]));
+            fprintf(stderr, "setup failed: %s", PQerrorMessage(conns[0].conn));
             exit(1);
         }
         PQclear(res);
@@ -491,7 +524,7 @@ run_permutation(TestSpec *testspec, int nsteps, Step **steps)
     {
         if (testspec->sessions[i]->setupsql)
         {
-            res = PQexec(conns[i + 1], testspec->sessions[i]->setupsql);
+            res = PQexec(conns[i + 1].conn, testspec->sessions[i]->setupsql);
             if (PQresultStatus(res) == PGRES_TUPLES_OK)
             {
                 printResultSet(res);
@@ -499,8 +532,8 @@ run_permutation(TestSpec *testspec, int nsteps, Step **steps)
             else if (PQresultStatus(res) != PGRES_COMMAND_OK)
             {
                 fprintf(stderr, "setup of session %s failed: %s",
-                        testspec->sessions[i]->name,
-                        PQerrorMessage(conns[i + 1]));
+                        conns[i + 1].sessionname,
+                        PQerrorMessage(conns[i + 1].conn));
                 exit(1);
             }
             PQclear(res);
@@ -510,73 +543,96 @@ run_permutation(TestSpec *testspec, int nsteps, Step **steps)
     /* Perform steps */
     for (i = 0; i < nsteps; i++)
     {
-        Step       *step = steps[i];
-        PGconn       *conn = conns[1 + step->session];
-        Step       *oldstep = NULL;
+        PermutationStep *pstep = steps[i];
+        Step       *step = pstep->step;
+        IsoConnInfo *iconn = &conns[1 + step->session];
+        PGconn       *conn = iconn->conn;
         bool        mustwait;
+        int            j;

         /*
          * Check whether the session that needs to perform the next step is
          * still blocked on an earlier step.  If so, wait for it to finish.
-         *
-         * (In older versions of this tool, we allowed precisely one session
-         * to be waiting at a time.  If we reached a step that required that
-         * session to execute the next command, we would declare the whole
-         * permutation invalid, cancel everything, and move on to the next
-         * one.  Unfortunately, that made it impossible to test the deadlock
-         * detector using this framework, unless the number of processes
-         * involved in the deadlock was precisely two.  We now assume that if
-         * we reach a step that is still blocked, we need to wait for it to
-         * unblock itself.)
          */
-        for (w = 0; w < nwaiting; ++w)
+        if (iconn->active_step != NULL)
         {
-            if (step->session == waiting[w]->session)
-            {
-                oldstep = waiting[w];
+            struct timeval start_time;

-                /* Wait for previous step on this connection. */
-                try_complete_step(testspec, oldstep, STEP_RETRY);
-
-                /* Remove that step from the waiting[] array. */
-                if (w + 1 < nwaiting)
-                    memmove(&waiting[w], &waiting[w + 1],
-                            (nwaiting - (w + 1)) * sizeof(Step *));
-                nwaiting--;
+            gettimeofday(&start_time, NULL);

-                break;
-            }
-        }
-        if (oldstep != NULL)
-        {
-            /*
-             * Check for completion of any steps that were previously waiting.
-             * Remove any that have completed from waiting[], and include them
-             * in the list for report_multiple_error_messages().
-             */
-            w = 0;
-            nerrorstep = 0;
-            while (w < nwaiting)
+            while (iconn->active_step != NULL)
             {
-                if (try_complete_step(testspec, waiting[w],
-                                      STEP_NONBLOCK | STEP_RETRY))
-                {
-                    /* Still blocked on a lock, leave it alone. */
-                    w++;
-                }
-                else
+                PermutationStep *oldstep = iconn->active_step;
+
+                /*
+                 * Wait for oldstep.  But even though we don't use
+                 * STEP_NONBLOCK, it might not complete because of blocker
+                 * conditions.
+                 */
+                if (!try_complete_step(testspec, oldstep, STEP_RETRY))
                 {
-                    /* This one finished, too! */
-                    errorstep[nerrorstep++] = waiting[w];
+                    /* Done, so remove oldstep from the waiting[] array. */
+                    int            w;
+
+                    for (w = 0; w < nwaiting; w++)
+                    {
+                        if (oldstep == waiting[w])
+                            break;
+                    }
+                    if (w >= nwaiting)
+                        abort();    /* can't happen */
                     if (w + 1 < nwaiting)
                         memmove(&waiting[w], &waiting[w + 1],
-                                (nwaiting - (w + 1)) * sizeof(Step *));
+                                (nwaiting - (w + 1)) * sizeof(PermutationStep *));
                     nwaiting--;
                 }
-            }

-            /* Report all errors together. */
-            report_multiple_error_messages(oldstep, nerrorstep, errorstep);
+                /*
+                 * Check for other steps that have finished.  We should do
+                 * this if oldstep completed, as it might have unblocked
+                 * something.  On the other hand, if oldstep hasn't completed,
+                 * we must poll all the active steps in hopes of unblocking
+                 * oldstep.  So either way, poll them.
+                 */
+                nwaiting = try_complete_steps(testspec, waiting, nwaiting,
+                                              STEP_NONBLOCK | STEP_RETRY);
+
+                /*
+                 * If the target session is still busy, apply a timeout to
+                 * keep from hanging indefinitely, which could happen with
+                 * incorrect blocker annotations.  Use the same 2 *
+                 * max_step_wait limit as try_complete_step does for deciding
+                 * to die.  (We don't bother with trying to cancel anything,
+                 * since it's unclear what to cancel in this case.)
+                 */
+                if (iconn->active_step != NULL)
+                {
+                    struct timeval current_time;
+                    int64        td;
+
+                    gettimeofday(¤t_time, NULL);
+                    td = (int64) current_time.tv_sec - (int64) start_time.tv_sec;
+                    td *= USECS_PER_SEC;
+                    td += (int64) current_time.tv_usec - (int64) start_time.tv_usec;
+                    if (td > 2 * max_step_wait)
+                    {
+                        fprintf(stderr, "step %s timed out after %d seconds\n",
+                                iconn->active_step->name,
+                                (int) (td / USECS_PER_SEC));
+                        fprintf(stderr, "active steps are:");
+                        for (j = 1; j < nconns; j++)
+                        {
+                            IsoConnInfo *oconn = &conns[j];
+
+                            if (oconn->active_step != NULL)
+                                fprintf(stderr, " %s",
+                                        oconn->active_step->name);
+                        }
+                        fprintf(stderr, "\n");
+                        exit(1);
+                    }
+                }
+            }
         }

         /* Send the query for this step. */
@@ -587,40 +643,37 @@ run_permutation(TestSpec *testspec, int nsteps, Step **steps)
             exit(1);
         }

-        /* Try to complete this step without blocking.  */
-        mustwait = try_complete_step(testspec, step, STEP_NONBLOCK);
+        /* Remember we launched a step. */
+        iconn->active_step = pstep;

-        /* Check for completion of any steps that were previously waiting. */
-        w = 0;
-        nerrorstep = 0;
-        while (w < nwaiting)
+        /* Remember target number of NOTICEs for any blocker conditions. */
+        for (j = 0; j < pstep->nblockers; j++)
         {
-            if (try_complete_step(testspec, waiting[w],
-                                  STEP_NONBLOCK | STEP_RETRY))
-                w++;
-            else
-            {
-                errorstep[nerrorstep++] = waiting[w];
-                if (w + 1 < nwaiting)
-                    memmove(&waiting[w], &waiting[w + 1],
-                            (nwaiting - (w + 1)) * sizeof(Step *));
-                nwaiting--;
-            }
+            PermutationStepBlocker *blocker = pstep->blockers[j];
+
+            if (blocker->blocktype == PSB_NUM_NOTICES)
+                blocker->target_notices = blocker->num_notices +
+                    conns[blocker->step->session + 1].total_notices;
         }

-        /* Report any error from this step, and any steps that it unblocked. */
-        report_multiple_error_messages(step, nerrorstep, errorstep);
+        /* Try to complete this step without blocking.  */
+        mustwait = try_complete_step(testspec, pstep, STEP_NONBLOCK);
+
+        /* Check for completion of any steps that were previously waiting. */
+        nwaiting = try_complete_steps(testspec, waiting, nwaiting,
+                                      STEP_NONBLOCK | STEP_RETRY);

         /* If this step is waiting, add it to the array of waiters. */
         if (mustwait)
-            waiting[nwaiting++] = step;
+            waiting[nwaiting++] = pstep;
     }

     /* Wait for any remaining queries. */
-    for (w = 0; w < nwaiting; ++w)
+    nwaiting = try_complete_steps(testspec, waiting, nwaiting, STEP_RETRY);
+    if (nwaiting != 0)
     {
-        try_complete_step(testspec, waiting[w], STEP_RETRY);
-        report_error_message(waiting[w]);
+        fprintf(stderr, "failed to complete permutation due to mutually-blocking steps\n");
+        exit(1);
     }

     /* Perform per-session teardown */
@@ -628,7 +681,7 @@ run_permutation(TestSpec *testspec, int nsteps, Step **steps)
     {
         if (testspec->sessions[i]->teardownsql)
         {
-            res = PQexec(conns[i + 1], testspec->sessions[i]->teardownsql);
+            res = PQexec(conns[i + 1].conn, testspec->sessions[i]->teardownsql);
             if (PQresultStatus(res) == PGRES_TUPLES_OK)
             {
                 printResultSet(res);
@@ -636,8 +689,8 @@ run_permutation(TestSpec *testspec, int nsteps, Step **steps)
             else if (PQresultStatus(res) != PGRES_COMMAND_OK)
             {
                 fprintf(stderr, "teardown of session %s failed: %s",
-                        testspec->sessions[i]->name,
-                        PQerrorMessage(conns[i + 1]));
+                        conns[i + 1].sessionname,
+                        PQerrorMessage(conns[i + 1].conn));
                 /* don't exit on teardown failure */
             }
             PQclear(res);
@@ -647,7 +700,7 @@ run_permutation(TestSpec *testspec, int nsteps, Step **steps)
     /* Perform teardown */
     if (testspec->teardownsql)
     {
-        res = PQexec(conns[0], testspec->teardownsql);
+        res = PQexec(conns[0].conn, testspec->teardownsql);
         if (PQresultStatus(res) == PGRES_TUPLES_OK)
         {
             printResultSet(res);
@@ -655,36 +708,90 @@ run_permutation(TestSpec *testspec, int nsteps, Step **steps)
         else if (PQresultStatus(res) != PGRES_COMMAND_OK)
         {
             fprintf(stderr, "teardown failed: %s",
-                    PQerrorMessage(conns[0]));
+                    PQerrorMessage(conns[0].conn));
             /* don't exit on teardown failure */
         }
         PQclear(res);
     }

     free(waiting);
-    free(errorstep);
+}
+
+/*
+ * Check for completion of any waiting step(s).
+ * Remove completed ones from the waiting[] array,
+ * and return the new value of nwaiting.
+ * See try_complete_step for the meaning of the flags.
+ */
+static int
+try_complete_steps(TestSpec *testspec, PermutationStep **waiting,
+                   int nwaiting, int flags)
+{
+    int            old_nwaiting;
+    bool        have_blocker;
+
+    do
+    {
+        int            w = 0;
+
+        /* Reset latch; we only care about notices received within loop. */
+        any_new_notice = false;
+
+        /* Likewise, these variables reset for each retry. */
+        old_nwaiting = nwaiting;
+        have_blocker = false;
+
+        /* Scan the array, try to complete steps. */
+        while (w < nwaiting)
+        {
+            if (try_complete_step(testspec, waiting[w], flags))
+            {
+                /* Still blocked, leave it alone. */
+                if (waiting[w]->nblockers > 0)
+                    have_blocker = true;
+                w++;
+            }
+            else
+            {
+                /* Done, remove it from array. */
+                if (w + 1 < nwaiting)
+                    memmove(&waiting[w], &waiting[w + 1],
+                            (nwaiting - (w + 1)) * sizeof(PermutationStep *));
+                nwaiting--;
+            }
+        }
+
+        /*
+         * If any of the still-waiting steps have blocker conditions attached,
+         * it's possible that one of the steps we examined afterwards has
+         * released them (either by completing, or by sending a NOTICE).  If
+         * any step completions or NOTICEs happened, repeat the loop until
+         * none occurs.  Without this provision, completion timing could vary
+         * depending on the order in which the steps appear in the array.
+         */
+    } while (have_blocker && (nwaiting < old_nwaiting || any_new_notice));
+    return nwaiting;
 }

 /*
  * Our caller already sent the query associated with this step.  Wait for it
- * to either complete or (if given the STEP_NONBLOCK flag) to block while
- * waiting for a lock.  We assume that any lock wait will persist until we
- * have executed additional steps in the permutation.
+ * to either complete, or hit a blocking condition.
  *
  * When calling this function on behalf of a given step for a second or later
- * time, pass the STEP_RETRY flag.  This only affects the messages printed.
- *
- * If the query returns an error, the message is saved in step->errormsg.
- * Caller should call report_error_message shortly after this, to have it
- * printed and cleared.
+ * time, pass the STEP_RETRY flag.  Do not pass it on the first call.
  *
- * If the STEP_NONBLOCK flag was specified and the query is waiting to acquire
- * a lock, returns true.  Otherwise, returns false.
+ * Returns true if the step was *not* completed, false if it was completed.
+ * Reasons for non-completion are (a) the STEP_NONBLOCK flag was specified
+ * and the query is waiting to acquire a lock, or (b) the step has an
+ * unsatisfied blocker condition.  When STEP_NONBLOCK is given, we assume
+ * that any lock wait will persist until we have executed additional steps.
  */
 static bool
-try_complete_step(TestSpec *testspec, Step *step, int flags)
+try_complete_step(TestSpec *testspec, PermutationStep *pstep, int flags)
 {
-    PGconn       *conn = conns[1 + step->session];
+    Step       *step = pstep->step;
+    IsoConnInfo *iconn = &conns[1 + step->session];
+    PGconn       *conn = iconn->conn;
     fd_set        read_set;
     struct timeval start_time;
     struct timeval timeout;
@@ -694,6 +801,28 @@ try_complete_step(TestSpec *testspec, Step *step, int flags)
     PGnotify   *notify;
     bool        canceled = false;

+    /*
+     * If the step is annotated with (*), then on the first call, force it to
+     * wait.  This is useful for ensuring consistent output when the step
+     * might or might not complete so fast that we don't observe it waiting.
+     */
+    if (!(flags & STEP_RETRY))
+    {
+        int            i;
+
+        for (i = 0; i < pstep->nblockers; i++)
+        {
+            PermutationStepBlocker *blocker = pstep->blockers[i];
+
+            if (blocker->blocktype == PSB_ONCE)
+            {
+                printf("step %s: %s <waiting ...>\n",
+                       step->name, step->sql);
+                return true;
+            }
+        }
+    }
+
     if (sock < 0)
     {
         fprintf(stderr, "invalid socket: %s", PQerrorMessage(conn));
@@ -727,14 +856,14 @@ try_complete_step(TestSpec *testspec, Step *step, int flags)
             {
                 bool        waiting;

-                res = PQexecPrepared(conns[0], PREP_WAITING, 1,
-                                     &backend_pid_strs[step->session + 1],
+                res = PQexecPrepared(conns[0].conn, PREP_WAITING, 1,
+                                     &conns[step->session + 1].backend_pid_str,
                                      NULL, NULL, 0);
                 if (PQresultStatus(res) != PGRES_TUPLES_OK ||
                     PQntuples(res) != 1)
                 {
                     fprintf(stderr, "lock wait query failed: %s",
-                            PQerrorMessage(conns[0]));
+                            PQerrorMessage(conns[0].conn));
                     exit(1);
                 }
                 waiting = ((PQgetvalue(res, 0, 0))[0] == 't');
@@ -833,6 +962,19 @@ try_complete_step(TestSpec *testspec, Step *step, int flags)
         }
     }

+    /*
+     * The step is done, but we won't report it as complete so long as there
+     * are blockers.
+     */
+    if (step_has_blocker(pstep))
+    {
+        if (!(flags & STEP_RETRY))
+            printf("step %s: %s <waiting ...>\n",
+                   step->name, step->sql);
+        return true;
+    }
+
+    /* Otherwise, go ahead and complete it. */
     if (flags & STEP_RETRY)
         printf("step %s: <... completed>\n", step->name);
     else
@@ -843,16 +985,12 @@ try_complete_step(TestSpec *testspec, Step *step, int flags)
         switch (PQresultStatus(res))
         {
             case PGRES_COMMAND_OK:
+            case PGRES_EMPTY_QUERY:
                 break;
             case PGRES_TUPLES_OK:
                 printResultSet(res);
                 break;
             case PGRES_FATAL_ERROR:
-                if (step->errormsg != NULL)
-                {
-                    printf("WARNING: this step had a leftover error message\n");
-                    printf("%s\n", step->errormsg);
-                }

                 /*
                  * Detail may contain XID values, so we want to just show
@@ -866,9 +1004,9 @@ try_complete_step(TestSpec *testspec, Step *step, int flags)
                                                          PG_DIAG_MESSAGE_PRIMARY);

                     if (sev && msg)
-                        step->errormsg = psprintf("%s:  %s", sev, msg);
+                        printf("%s:  %s\n", sev, msg);
                     else
-                        step->errormsg = pg_strdup(PQresultErrorMessage(res));
+                        printf("%s\n", PQresultErrorMessage(res));
                 }
                 break;
             default:
@@ -885,12 +1023,13 @@ try_complete_step(TestSpec *testspec, Step *step, int flags)
         /* Try to identify which session it came from */
         const char *sendername = NULL;
         char        pidstring[32];
+        int            i;

-        for (int i = 0; i < testspec->nsessions; i++)
+        for (i = 0; i < testspec->nsessions; i++)
         {
-            if (notify->be_pid == backend_pids[i + 1])
+            if (notify->be_pid == conns[i + 1].backend_pid)
             {
-                sendername = testspec->sessions[i]->name;
+                sendername = conns[i + 1].sessionname;
                 break;
             }
         }
@@ -907,6 +1046,43 @@ try_complete_step(TestSpec *testspec, Step *step, int flags)
         PQconsumeInput(conn);
     }

+    /* Connection is now idle. */
+    iconn->active_step = NULL;
+
+    return false;
+}
+
+/* Detect whether a step has any unsatisfied blocker conditions */
+static bool
+step_has_blocker(PermutationStep *pstep)
+{
+    int            i;
+
+    for (i = 0; i < pstep->nblockers; i++)
+    {
+        PermutationStepBlocker *blocker = pstep->blockers[i];
+        IsoConnInfo *iconn;
+
+        switch (blocker->blocktype)
+        {
+            case PSB_ONCE:
+                /* Ignore; try_complete_step handles this specially */
+                break;
+            case PSB_OTHER_STEP:
+                /* Block if referenced step is active */
+                iconn = &conns[1 + blocker->step->session];
+                if (iconn->active_step &&
+                    iconn->active_step->step == blocker->step)
+                    return true;
+                break;
+            case PSB_NUM_NOTICES:
+                /* Block if not enough notices received yet */
+                iconn = &conns[1 + blocker->step->session];
+                if (iconn->total_notices < blocker->target_notices)
+                    return true;
+                break;
+        }
+    }
     return false;
 }

@@ -932,11 +1108,17 @@ printResultSet(PGresult *res)
     }
 }

-/* notice processor, prefixes each message with the session name */
+/* notice processor for regular user sessions */
 static void
 isotesterNoticeProcessor(void *arg, const char *message)
 {
-    printf("%s: %s", (char *) arg, message);
+    IsoConnInfo *myconn = (IsoConnInfo *) arg;
+
+    /* Prefix the backend's message with the session name. */
+    printf("%s: %s", myconn->sessionname, message);
+    /* Record notices, since we may need this to decide to unblock a step. */
+    myconn->total_notices++;
+    any_new_notice = true;
 }

 /* notice processor, hides the message */
diff --git a/src/test/isolation/isolationtester.h b/src/test/isolation/isolationtester.h
index 488ff05928..5f300219c2 100644
--- a/src/test/isolation/isolationtester.h
+++ b/src/test/isolation/isolationtester.h
@@ -14,31 +14,62 @@
 #ifndef ISOLATIONTESTER_H
 #define ISOLATIONTESTER_H

-typedef struct Session Session;
+/*
+ * The structs declared here are used in the output of specparse.y.
+ * Except where noted, all fields are set in the grammar and not
+ * changed thereafter.
+ */
 typedef struct Step Step;

-struct Session
+typedef struct
 {
     char       *name;
     char       *setupsql;
     char       *teardownsql;
     Step      **steps;
     int            nsteps;
-};
+} Session;

 struct Step
 {
-    int            session;
-    bool        used;
     char       *name;
     char       *sql;
-    char       *errormsg;
+    /* These fields are filled by check_testspec(): */
+    int            session;        /* identifies owning session */
+    bool        used;            /* has step been used in a permutation? */
 };

+typedef enum
+{
+    PSB_ONCE,                    /* force step to wait once */
+    PSB_OTHER_STEP,                /* wait for another step to complete first */
+    PSB_NUM_NOTICES                /* wait for N notices from another session */
+} PermutationStepBlockerType;
+
+typedef struct
+{
+    char       *stepname;
+    PermutationStepBlockerType blocktype;
+    int            num_notices;    /* only used for PSB_NUM_NOTICES */
+    /* These fields are filled by check_testspec(): */
+    Step       *step;            /* link to referenced step (if any) */
+    /* These fields are runtime workspace: */
+    int            target_notices; /* total notices needed from other session */
+} PermutationStepBlocker;
+
+typedef struct
+{
+    char       *name;            /* name of referenced Step */
+    PermutationStepBlocker **blockers;
+    int            nblockers;
+    /* These fields are filled by check_testspec(): */
+    Step       *step;            /* link to referenced Step */
+} PermutationStep;
+
 typedef struct
 {
     int            nsteps;
-    char      **stepnames;
+    PermutationStep **steps;
 } Permutation;

 typedef struct
@@ -50,8 +81,6 @@ typedef struct
     int            nsessions;
     Permutation **permutations;
     int            npermutations;
-    Step      **allsteps;
-    int            nallsteps;
 } TestSpec;

 extern TestSpec parseresult;
diff --git a/src/test/isolation/specparse.y b/src/test/isolation/specparse.y
index ae3a999961..04dbb576a7 100644
--- a/src/test/isolation/specparse.y
+++ b/src/test/isolation/specparse.y
@@ -25,9 +25,12 @@ TestSpec        parseresult;            /* result of parsing is left here */
 %union
 {
     char       *str;
+    int            integer;
     Session       *session;
     Step       *step;
     Permutation *permutation;
+    PermutationStep *permutationstep;
+    PermutationStepBlocker *blocker;
     struct
     {
         void  **elements;
@@ -39,13 +42,16 @@ TestSpec        parseresult;            /* result of parsing is left here */
 %type <str>  opt_setup opt_teardown
 %type <str> setup
 %type <ptr_list> step_list session_list permutation_list opt_permutation_list
-%type <ptr_list> string_literal_list
+%type <ptr_list> permutation_step_list blocker_list
 %type <session> session
 %type <step> step
 %type <permutation> permutation
+%type <permutationstep> permutation_step
+%type <blocker> blocker

 %token <str> sqlblock string_literal
-%token PERMUTATION SESSION SETUP STEP TEARDOWN TEST
+%token <integer> INTEGER
+%token NOTICES PERMUTATION SESSION SETUP STEP TEARDOWN TEST

 %%

@@ -145,8 +151,8 @@ step:
                 $$ = pg_malloc(sizeof(Step));
                 $$->name = $2;
                 $$->sql = $3;
+                $$->session = -1; /* until filled */
                 $$->used = false;
-                $$->errormsg = NULL;
             }
         ;

@@ -180,23 +186,23 @@ permutation_list:


 permutation:
-            PERMUTATION string_literal_list
+            PERMUTATION permutation_step_list
             {
                 $$ = pg_malloc(sizeof(Permutation));
-                $$->stepnames = (char **) $2.elements;
                 $$->nsteps = $2.nelements;
+                $$->steps = (PermutationStep **) $2.elements;
             }
         ;

-string_literal_list:
-            string_literal_list string_literal
+permutation_step_list:
+            permutation_step_list permutation_step
             {
                 $$.elements = pg_realloc($1.elements,
                                          ($1.nelements + 1) * sizeof(void *));
                 $$.elements[$1.nelements] = $2;
                 $$.nelements = $1.nelements + 1;
             }
-            | string_literal
+            | permutation_step
             {
                 $$.nelements = 1;
                 $$.elements = pg_malloc(sizeof(void *));
@@ -204,6 +210,71 @@ string_literal_list:
             }
         ;

+permutation_step:
+            string_literal
+            {
+                $$ = pg_malloc(sizeof(PermutationStep));
+                $$->name = $1;
+                $$->blockers = NULL;
+                $$->nblockers = 0;
+                $$->step = NULL;
+            }
+            | string_literal '(' blocker_list ')'
+            {
+                $$ = pg_malloc(sizeof(PermutationStep));
+                $$->name = $1;
+                $$->blockers = (PermutationStepBlocker **) $3.elements;
+                $$->nblockers = $3.nelements;
+                $$->step = NULL;
+            }
+        ;
+
+blocker_list:
+            blocker_list ',' blocker
+            {
+                $$.elements = pg_realloc($1.elements,
+                                         ($1.nelements + 1) * sizeof(void *));
+                $$.elements[$1.nelements] = $3;
+                $$.nelements = $1.nelements + 1;
+            }
+            | blocker
+            {
+                $$.nelements = 1;
+                $$.elements = pg_malloc(sizeof(void *));
+                $$.elements[0] = $1;
+            }
+        ;
+
+blocker:
+            string_literal
+            {
+                $$ = pg_malloc(sizeof(PermutationStepBlocker));
+                $$->stepname = $1;
+                $$->blocktype = PSB_OTHER_STEP;
+                $$->num_notices = -1;
+                $$->step = NULL;
+                $$->target_notices = -1;
+            }
+            | string_literal NOTICES INTEGER
+            {
+                $$ = pg_malloc(sizeof(PermutationStepBlocker));
+                $$->stepname = $1;
+                $$->blocktype = PSB_NUM_NOTICES;
+                $$->num_notices = $3;
+                $$->step = NULL;
+                $$->target_notices = -1;
+            }
+            | '*'
+            {
+                $$ = pg_malloc(sizeof(PermutationStepBlocker));
+                $$->stepname = NULL;
+                $$->blocktype = PSB_ONCE;
+                $$->num_notices = -1;
+                $$->step = NULL;
+                $$->target_notices = -1;
+            }
+        ;
+
 %%

 #include "specscanner.c"
diff --git a/src/test/isolation/specs/deadlock-hard.spec b/src/test/isolation/specs/deadlock-hard.spec
index 67aad66e66..3316d75e95 100644
--- a/src/test/isolation/specs/deadlock-hard.spec
+++ b/src/test/isolation/specs/deadlock-hard.spec
@@ -63,9 +63,17 @@ step "s7a8"    { LOCK TABLE a8; }
 step "s7c"    { COMMIT; }

 session "s8"
-setup        { BEGIN; SET deadlock_timeout = '10s'; }
+setup        { BEGIN; SET deadlock_timeout = '10ms'; }
 step "s8a8"    { LOCK TABLE a8; }
 step "s8a1"    { LOCK TABLE a1; }
 step "s8c"    { COMMIT; }

-permutation "s1a1" "s2a2" "s3a3" "s4a4" "s5a5" "s6a6" "s7a7" "s8a8" "s1a2" "s2a3" "s3a4" "s4a5" "s5a6" "s6a7" "s7a8"
"s8a1""s8c" "s7c" "s6c" "s5c" "s4c" "s3c" "s2c" "s1c" 
+# Note: when s8a1 detects the deadlock and fails, s7a8 is released, making
+# it timing-dependent which query completion is received first by the tester.
+# To ensure output stability, add a blocking mark to force s8a1's completion
+# to be reported first.  There is a second timing dependency, too: the tester
+# might or might not observe s8a1 during its short lock wait state.  Apply a
+# dummy blocking mark to s8a1 to ensure it will be reported as "waiting"
+# regardless of that.
+
+permutation "s1a1" "s2a2" "s3a3" "s4a4" "s5a5" "s6a6" "s7a7" "s8a8" "s1a2" "s2a3" "s3a4" "s4a5" "s5a6" "s6a7"
"s7a8"("s8a1")"s8a1"(*) "s8c" "s7c" "s6c" "s5c" "s4c" "s3c" "s2c" "s1c" 
diff --git a/src/test/isolation/specs/deadlock-soft-2.spec b/src/test/isolation/specs/deadlock-soft-2.spec
index 46b73bc082..6ff915f606 100644
--- a/src/test/isolation/specs/deadlock-soft-2.spec
+++ b/src/test/isolation/specs/deadlock-soft-2.spec
@@ -2,12 +2,6 @@
 # jump over both s3 and s4 and acquire the lock on a2 immediately,
 # since s3 and s4 are hard-blocked on a1.

-# The expected output for this test assumes that isolationtester will
-# detect step s1b as waiting before the deadlock detector runs and
-# releases s1 from its blocked state.  To leave enough time for that
-# to happen even in very slow (CLOBBER_CACHE_ALWAYS) cases, we must
-# increase deadlock_timeout.
-
 setup
 {
   CREATE TABLE a1 ();
@@ -20,7 +14,7 @@ teardown
 }

 session "s1"
-setup        { BEGIN; SET deadlock_timeout = '5s'; }
+setup        { BEGIN; SET deadlock_timeout = '10ms'; }
 step "s1a"    { LOCK TABLE a1 IN SHARE UPDATE EXCLUSIVE MODE; }
 step "s1b"    { LOCK TABLE a2 IN SHARE UPDATE EXCLUSIVE MODE; }
 step "s1c"    { COMMIT; }
@@ -41,4 +35,9 @@ setup        { BEGIN; SET deadlock_timeout = '100s'; }
 step "s4a"    { LOCK TABLE a2 IN ACCESS EXCLUSIVE MODE; }
 step "s4c"    { COMMIT; }

-permutation "s1a" "s2a" "s2b" "s3a" "s4a" "s1b" "s1c" "s2c" "s3c" "s4c"
+# The expected output for this test assumes that isolationtester will
+# detect step s1b as waiting before the deadlock detector runs and
+# releases s1 from its blocked state.  To ensure that happens even in
+# very slow (CLOBBER_CACHE_ALWAYS) cases, apply a (*) annotation.
+
+permutation "s1a" "s2a" "s2b" "s3a" "s4a" "s1b"(*) "s1c" "s2c" "s3c" "s4c"
diff --git a/src/test/isolation/specs/detach-partition-concurrently-3.spec
b/src/test/isolation/specs/detach-partition-concurrently-3.spec
index 13ad84ac03..5c8d45fee5 100644
--- a/src/test/isolation/specs/detach-partition-concurrently-3.spec
+++ b/src/test/isolation/specs/detach-partition-concurrently-3.spec
@@ -1,8 +1,11 @@
 # Try various things to happen to a partition with an incomplete detach
 #
-# Note: Always keep "s2noop" right after "s1cancel" in permutations.  This
-# reduces the probability of the timing problem that the cancel error report
-# is shown together with the next query instead of with the cancel query.
+# Note: When using "s1cancel", mark the target step (the one to be canceled)
+# as being blocked by "s1cancel".  This ensures consistent reporting regardless
+# of whether "s1cancel" returns before or after the other step reports failure.
+# Also, ensure the step after "s1cancel" is also an s1 step (use "s1noop" if
+# necessary).  This ensures we won't move on to the next step until the cancel
+# is complete.

 setup
 {
@@ -22,8 +25,8 @@ step "s1b"            { BEGIN; }
 step "s1brr"        { BEGIN ISOLATION LEVEL REPEATABLE READ; }
 step "s1s"            { SELECT * FROM d3_listp; }
 step "s1spart"        { SELECT * FROM d3_listp1; }
-# Sleep 0.1s after sending cancel, to give s2 time to react
-step "s1cancel"     { SELECT pg_cancel_backend(pid), pg_sleep(0.1) FROM d3_pid; }
+step "s1cancel"     { SELECT pg_cancel_backend(pid) FROM d3_pid; }
+step "s1noop"        { }
 step "s1c"            { COMMIT; }
 step "s1alter"        { ALTER TABLE d3_listp1 ALTER a DROP NOT NULL; }
 step "s1insert"        { INSERT INTO d3_listp VALUES (1); }
@@ -41,44 +44,43 @@ step "s2begin"        { BEGIN; }
 step "s2snitch"        { INSERT INTO d3_pid SELECT pg_backend_pid(); }
 step "s2detach"        { ALTER TABLE d3_listp DETACH PARTITION d3_listp1 CONCURRENTLY; }
 step "s2detach2"    { ALTER TABLE d3_listp DETACH PARTITION d3_listp2 CONCURRENTLY; }
-step "s2noop"        { UNLISTEN noop; }
 step "s2detachfinal"    { ALTER TABLE d3_listp DETACH PARTITION d3_listp1 FINALIZE; }
 step "s2drop"        { DROP TABLE d3_listp1; }
 step "s2commit"        { COMMIT; }

 # Try various things while the partition is in "being detached" state, with
 # no session waiting.
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s1describe" "s1alter"
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1insert" "s1c"
-permutation "s2snitch" "s1brr" "s1s" "s2detach" "s1cancel" "s2noop" "s1insert" "s1c" "s1spart"
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s1insertpart"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s1describe" "s1alter"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1insert" "s1c"
+permutation "s2snitch" "s1brr" "s1s" "s2detach"("s1cancel") "s1cancel" "s1insert" "s1c" "s1spart"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s1insertpart"

 # Test partition descriptor caching
-permutation "s2snitch" "s1b" "s1s" "s2detach2" "s1cancel" "s2noop" "s1c" "s1brr" "s1insert" "s1s" "s1insert" "s1c"
-permutation "s2snitch" "s1b" "s1s" "s2detach2" "s1cancel" "s2noop" "s1c" "s1brr" "s1s" "s1insert" "s1s" "s1c"
+permutation "s2snitch" "s1b" "s1s" "s2detach2"("s1cancel") "s1cancel" "s1c" "s1brr" "s1insert" "s1s" "s1insert" "s1c"
+permutation "s2snitch" "s1b" "s1s" "s2detach2"("s1cancel") "s1cancel" "s1c" "s1brr" "s1s" "s1insert" "s1s" "s1c"

 # "drop" here does both tables
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s1drop" "s1list"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s1drop" "s1list"
 # "truncate" only does parent, not partition
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s1trunc" "s1spart"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s1trunc" "s1spart"

 # If a partition pending detach exists, we cannot drop another one
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s2detach2" "s1c"
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s2detachfinal" "s1c" "s2detach2"
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s1droppart" "s2detach2"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1noop" "s2detach2" "s1c"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1noop" "s2detachfinal" "s1c" "s2detach2"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s1droppart" "s2detach2"

 # When a partition with incomplete detach is dropped, we grab lock on parent too.
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s2begin" "s2drop" "s1s" "s2commit"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s2begin" "s2drop" "s1s" "s2commit"

 # Partially detach, then select and try to complete the detach.  Reading
 # from partition blocks (AEL is required on partition); reading from parent
 # does not block.
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s1b" "s1spart" "s2detachfinal" "s1c"
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s1b" "s1s" "s2detachfinal" "s1c"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s1b" "s1spart" "s2detachfinal" "s1c"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s1b" "s1s" "s2detachfinal" "s1c"

 # DETACH FINALIZE in a transaction block. No insert/select on the partition
 # is allowed concurrently with that.
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s1b" "s1spart" "s2detachfinal" "s1c"
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s2begin" "s2detachfinal" "s2commit"
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s2begin" "s2detachfinal" "s1spart" "s2commit"
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s1c" "s2begin" "s2detachfinal" "s1insertpart"
"s2commit"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s1b" "s1spart" "s2detachfinal" "s1c"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s2begin" "s2detachfinal" "s2commit"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s2begin" "s2detachfinal" "s1spart"
"s2commit"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1c" "s2begin" "s2detachfinal" "s1insertpart"
"s2commit"
diff --git a/src/test/isolation/specs/detach-partition-concurrently-4.spec
b/src/test/isolation/specs/detach-partition-concurrently-4.spec
index 5e4c0018d1..208808bc3d 100644
--- a/src/test/isolation/specs/detach-partition-concurrently-4.spec
+++ b/src/test/isolation/specs/detach-partition-concurrently-4.spec
@@ -4,9 +4,12 @@
 # because the locking situation is completely different.  I didn't verify
 # that keeping both variants adds any extra coverage.)
 #
-# Note: Always keep "s2noop" right after "s1cancel" in permutations.  This
-# reduces the probability of the timing problem that the cancel error report
-# is shown together with the next query instead of with the cancel query.
+# Note: When using "s1cancel", mark the target step (the one to be canceled)
+# as being blocked by "s1cancel".  This ensures consistent reporting regardless
+# of whether "s1cancel" returns before or after the other step reports failure.
+# Also, ensure the step after "s1cancel" is also an s1 step (use "s1noop" if
+# necessary).  This ensures we won't move on to the next step until the cancel
+# is complete.

 setup {
     drop table if exists d4_primary, d4_primary1, d4_fk, d4_pid;
@@ -24,8 +27,8 @@ session "s1"
 step "s1b"            { begin; }
 step "s1brr"        { begin isolation level repeatable read; }
 step "s1s"            { select * from d4_primary; }
-# Sleep 0.1s after sending cancel, to give s2 time to react
-step "s1cancel"     { select pg_cancel_backend(pid), pg_sleep(0.1) from d4_pid; }
+step "s1cancel"     { select pg_cancel_backend(pid) from d4_pid; }
+step "s1noop"        { }
 step "s1insert"        { insert into d4_fk values (1); }
 step "s1c"            { commit; }
 step "s1declare"    { declare f cursor for select * from d4_primary; }
@@ -39,7 +42,6 @@ step "s1rollback"    { rollback to f; }
 session "s2"
 step "s2snitch" { insert into d4_pid select pg_backend_pid(); }
 step "s2detach" { alter table d4_primary detach partition d4_primary1 concurrently; }
-step "s2noop"    { UNLISTEN noop; }

 session "s3"
 step "s3brr"        { begin isolation level repeatable read; }
@@ -48,34 +50,34 @@ step "s3commit"        { commit; }
 step "s3vacfreeze"    { vacuum freeze pg_catalog.pg_inherits; }

 # Trying to insert into a partially detached partition is rejected
-permutation "s2snitch" "s1b"   "s1s" "s2detach" "s1cancel" "s2noop" "s1insert" "s1c"
+permutation "s2snitch" "s1b"   "s1s" "s2detach"("s1cancel") "s1cancel" "s1insert" "s1c"
 permutation "s2snitch" "s1b"   "s1s" "s2detach"            "s1insert" "s1c"
 # ... even under REPEATABLE READ mode.
-permutation "s2snitch" "s1brr" "s1s" "s2detach" "s1cancel" "s2noop" "s1insert" "s1c"
+permutation "s2snitch" "s1brr" "s1s" "s2detach"("s1cancel") "s1cancel" "s1insert" "s1c"
 permutation "s2snitch" "s1brr" "s1s" "s2detach"            "s1insert" "s1c"

 # If you read the referenced table using a cursor, you can see a row that the
 # RI query does not see.
-permutation "s2snitch" "s1b" "s1declare" "s2detach" "s1cancel" "s2noop" "s1fetchall" "s1insert" "s1c"
+permutation "s2snitch" "s1b" "s1declare" "s2detach"("s1cancel") "s1cancel" "s1fetchall" "s1insert" "s1c"
 permutation "s2snitch" "s1b" "s1declare" "s2detach"            "s1fetchall" "s1insert" "s1c"
-permutation "s2snitch" "s1b" "s1declare" "s2detach" "s1cancel" "s2noop" "s1svpt" "s1insert" "s1rollback" "s1fetchall"
"s1c"
+permutation "s2snitch" "s1b" "s1declare" "s2detach"("s1cancel") "s1cancel" "s1svpt" "s1insert" "s1rollback"
"s1fetchall""s1c" 
 permutation "s2snitch" "s1b" "s1declare" "s2detach"            "s1svpt" "s1insert" "s1rollback" "s1fetchall" "s1c"
-permutation "s2snitch" "s1b" "s2detach" "s1declare" "s1cancel" "s2noop" "s1fetchall" "s1insert" "s1c"
+permutation "s2snitch" "s1b" "s2detach"("s1cancel") "s1declare" "s1cancel" "s1fetchall" "s1insert" "s1c"
 permutation "s2snitch" "s1b" "s2detach" "s1declare"            "s1fetchall" "s1insert" "s1c"
-permutation "s2snitch" "s1b" "s2detach" "s1declare" "s1cancel" "s2noop" "s1svpt" "s1insert" "s1rollback" "s1fetchall"
"s1c"
+permutation "s2snitch" "s1b" "s2detach"("s1cancel") "s1declare" "s1cancel" "s1svpt" "s1insert" "s1rollback"
"s1fetchall""s1c" 
 permutation "s2snitch" "s1b" "s2detach" "s1declare"            "s1svpt" "s1insert" "s1rollback" "s1fetchall" "s1c"

 # Creating the referencing row using a cursor
-permutation "s2snitch" "s1brr" "s1declare2" "s1fetchone" "s2detach" "s1cancel" "s2noop" "s1updcur" "s1c"
+permutation "s2snitch" "s1brr" "s1declare2" "s1fetchone" "s2detach"("s1cancel") "s1cancel" "s1updcur" "s1c"
 permutation "s2snitch" "s1brr" "s1declare2" "s1fetchone" "s2detach"            "s1updcur" "s1c"
 permutation "s2snitch" "s1brr" "s1declare2" "s1fetchone" "s1updcur" "s2detach" "s1c"

 # Try reading the table from an independent session.
 permutation "s2snitch" "s1b" "s1s" "s2detach" "s3insert" "s1c"
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s3brr" "s3insert" "s3commit" "s1cancel" "s2noop" "s1c"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s3brr" "s3insert" "s3commit" "s1cancel" "s1c"
 permutation "s2snitch" "s1b" "s1s" "s2detach" "s3brr" "s3insert" "s3commit" "s1c"

 # Try one where we VACUUM FREEZE pg_inherits (to verify that xmin change is
 # handled correctly).
-permutation "s2snitch" "s1brr" "s1s" "s2detach" "s1cancel" "s2noop" "s3vacfreeze" "s1s" "s1insert" "s1c"
-permutation "s2snitch" "s1b" "s1s" "s2detach" "s1cancel" "s2noop" "s3vacfreeze" "s1s" "s1insert" "s1c"
+permutation "s2snitch" "s1brr" "s1s" "s2detach"("s1cancel") "s1cancel" "s1noop" "s3vacfreeze" "s1s" "s1insert" "s1c"
+permutation "s2snitch" "s1b" "s1s" "s2detach"("s1cancel") "s1cancel" "s1noop" "s3vacfreeze" "s1s" "s1insert" "s1c"
diff --git a/src/test/isolation/specs/insert-conflict-specconflict.spec
b/src/test/isolation/specs/insert-conflict-specconflict.spec
index 6028397491..3bc2bf0630 100644
--- a/src/test/isolation/specs/insert-conflict-specconflict.spec
+++ b/src/test/isolation/specs/insert-conflict-specconflict.spec
@@ -83,6 +83,7 @@ step "s1_confirm_index_order" { SELECT 'upserttest_key_uniq_idx'::regclass::int8
 step "s1_upsert" { INSERT INTO upserttest(key, data) VALUES('k1', 'inserted s1') ON CONFLICT (blurt_and_lock_123(key))
DOUPDATE SET data = upserttest.data || ' with conflict update s1'; } 
 step "s1_insert_toast" { INSERT INTO upserttest VALUES('k2', ctoast_large_val()) ON CONFLICT DO NOTHING; }
 step "s1_commit"  { COMMIT; }
+step "s1_noop"    { }

 session "s2"
 setup
@@ -95,6 +96,7 @@ step "s2_begin"  { BEGIN; }
 step "s2_upsert" { INSERT INTO upserttest(key, data) VALUES('k1', 'inserted s2') ON CONFLICT (blurt_and_lock_123(key))
DOUPDATE SET data = upserttest.data || ' with conflict update s2'; } 
 step "s2_insert_toast" { INSERT INTO upserttest VALUES('k2', ctoast_large_val()) ON CONFLICT DO NOTHING; }
 step "s2_commit"  { COMMIT; }
+step "s2_noop"    { }

 # Test that speculative locks are correctly acquired and released, s2
 # inserts, s1 updates.
@@ -223,7 +225,8 @@ permutation
    "controller_show"
    "s2_begin"
    # Both sessions wait on advisory locks
-   "s1_upsert" "s2_upsert"
+   # (but don't show s2_upsert as complete till we've seen all of s1's notices)
+   "s1_upsert" "s2_upsert" ("s1_upsert" notices 10)
    "controller_show"
    # Switch both sessions to wait on the other lock next time (the speculative insertion)
    "controller_unlock_1_1" "controller_unlock_2_1"
@@ -244,14 +247,15 @@ permutation
    "controller_unlock_1_2"
    # Should report s1 is waiting on speculative lock
    "controller_print_speculative_locks"
-   # Allow s2 to insert into the non-unique index and complete s1 will
+   # Allow s2 to insert into the non-unique index and complete.  s1 will
    # no longer wait on speculative lock, but proceed to wait on the
-   # transaction to finish.
-   "controller_unlock_2_4"
-   # Should report that s1 is now waiting for s1 to commit
+   # transaction to finish.  The no-op step is needed to ensure that
+   # we don't advance to the reporting step until s2_upsert has completed.
+   "controller_unlock_2_4" "s2_noop"
+   # Should report that s1 is now waiting for s2 to commit
    "controller_print_speculative_locks"
    # Once s2 commits, s1 is finally free to continue to update
-   "s2_commit"
+   "s2_commit" "s1_noop"
    # This should now show a successful UPSERT
    "controller_show"
    # Ensure no unexpected locks survive
diff --git a/src/test/isolation/specs/multiple-cic.spec b/src/test/isolation/specs/multiple-cic.spec
index 3199667be2..3ac1d39d86 100644
--- a/src/test/isolation/specs/multiple-cic.spec
+++ b/src/test/isolation/specs/multiple-cic.spec
@@ -37,4 +37,7 @@ step "s2i"    {
         WHERE unlck();
     }

-permutation "s2l" "s1i" "s2i"
+# (*) marker ensures that s2i is reported as "waiting", even if it
+# completes very quickly
+
+permutation "s2l" "s1i" "s2i"(*)
diff --git a/src/test/isolation/specs/timeouts.spec b/src/test/isolation/specs/timeouts.spec
index 7f821d44d0..e167e1885a 100644
--- a/src/test/isolation/specs/timeouts.spec
+++ b/src/test/isolation/specs/timeouts.spec
@@ -19,27 +19,31 @@ teardown    { ABORT; }

 session "s2"
 setup        { BEGIN ISOLATION LEVEL READ COMMITTED; }
-step "sto"    { SET statement_timeout = 5000; }
-step "lto"    { SET lock_timeout = 5000; }
-step "lsto"    { SET lock_timeout = 5000; SET statement_timeout = 6000; }
-step "slto"    { SET lock_timeout = 6000; SET statement_timeout = 5000; }
+step "sto"    { SET statement_timeout = '10ms'; }
+step "lto"    { SET lock_timeout = '10ms'; }
+step "lsto"    { SET lock_timeout = '10ms'; SET statement_timeout = '10s'; }
+step "slto"    { SET lock_timeout = '10s'; SET statement_timeout = '10ms'; }
 step "locktbl"    { LOCK TABLE accounts; }
 step "update"    { DELETE FROM accounts WHERE accountid = 'checking'; }
 teardown    { ABORT; }

+# It's possible that the isolation tester will not observe the final
+# steps as "waiting", thanks to the relatively short timeouts we use.
+# We can ensure consistent test output by marking those steps with (*).
+
 # statement timeout, table-level lock
-permutation "rdtbl" "sto" "locktbl"
+permutation "rdtbl" "sto" "locktbl"(*)
 # lock timeout, table-level lock
-permutation "rdtbl" "lto" "locktbl"
+permutation "rdtbl" "lto" "locktbl"(*)
 # lock timeout expires first, table-level lock
-permutation "rdtbl" "lsto" "locktbl"
+permutation "rdtbl" "lsto" "locktbl"(*)
 # statement timeout expires first, table-level lock
-permutation "rdtbl" "slto" "locktbl"
+permutation "rdtbl" "slto" "locktbl"(*)
 # statement timeout, row-level lock
-permutation "wrtbl" "sto" "update"
+permutation "wrtbl" "sto" "update"(*)
 # lock timeout, row-level lock
-permutation "wrtbl" "lto" "update"
+permutation "wrtbl" "lto" "update"(*)
 # lock timeout expires first, row-level lock
-permutation "wrtbl" "lsto" "update"
+permutation "wrtbl" "lsto" "update"(*)
 # statement timeout expires first, row-level lock
-permutation "wrtbl" "slto" "update"
+permutation "wrtbl" "slto" "update"(*)
diff --git a/src/test/isolation/specs/tuplelock-update.spec b/src/test/isolation/specs/tuplelock-update.spec
index 8f5a1f7314..d3de0bcbc7 100644
--- a/src/test/isolation/specs/tuplelock-update.spec
+++ b/src/test/isolation/specs/tuplelock-update.spec
@@ -18,8 +18,8 @@ step "s1_chain" { UPDATE pktab SET data = DEFAULT; }
 step "s1_begin" { BEGIN; }
 step "s1_grablock" { SELECT * FROM pktab FOR KEY SHARE; }
 step "s1_advunlock1" { SELECT pg_advisory_unlock(142857); }
-step "s1_advunlock2" { SELECT pg_sleep(5), pg_advisory_unlock(285714); }
-step "s1_advunlock3" { SELECT pg_sleep(5), pg_advisory_unlock(571428); }
+step "s1_advunlock2" { SELECT pg_advisory_unlock(285714); }
+step "s1_advunlock3" { SELECT pg_advisory_unlock(571428); }
 step "s1_commit" { COMMIT; }

 session "s2"
@@ -31,4 +31,7 @@ step "s3_update" { UPDATE pktab SET data = DEFAULT WHERE pg_advisory_lock_shared
 session "s4"
 step "s4_update" { UPDATE pktab SET data = DEFAULT WHERE pg_advisory_lock_shared(571428) IS NOT NULL; }

-permutation "s1_advlock" "s2_update" "s3_update" "s4_update" "s1_chain" "s1_begin" "s1_grablock" "s1_advunlock1"
"s1_advunlock2""s1_advunlock3" "s1_commit" 
+# We use blocker annotations on the s1_advunlockN steps so that we will not
+# move on to the next step until the other session's released step finishes.
+# This ensures stable ordering of the test output.
+permutation "s1_advlock" "s2_update" "s3_update" "s4_update" "s1_chain" "s1_begin" "s1_grablock"
"s1_advunlock1"("s2_update")"s1_advunlock2"("s3_update") "s1_advunlock3"("s4_update") "s1_commit" 
diff --git a/src/test/isolation/specscanner.l b/src/test/isolation/specscanner.l
index 19883c265b..a733bcf355 100644
--- a/src/test/isolation/specscanner.l
+++ b/src/test/isolation/specscanner.l
@@ -36,6 +36,10 @@ static void addlitchar(char c);
 %x sql
 %x qstr

+digit            [0123456789]
+
+self            [,()*]
+
 non_newline        [^\n\r]
 space            [ \t\r\f]

@@ -48,12 +52,20 @@ comment            ("#"{non_newline}*)
     litbufsize = LITBUF_INIT;
 %}

+notices            { return NOTICES; }
 permutation        { return PERMUTATION; }
 session            { return SESSION; }
 setup            { return SETUP; }
 step            { return STEP; }
 teardown        { return TEARDOWN; }

+{digit}+        {
+                    yylval.integer = atoi(yytext);
+                    return INTEGER;
+                }
+
+{self}            { return yytext[0]; }
+
 [\n]            { yyline++; }
 {comment}        { /* ignore */ }
 {space}            { /* ignore */ }

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