From d60b190a7a64600bb952c42a3565973d96bcf456 Mon Sep 17 00:00:00 2001
From: Masahiko Sawada <sawada.mshk@gmail.com>
Date: Wed, 19 Oct 2022 12:16:43 +0900
Subject: [PATCH v1] Don't assign subtransactions to top transaction in
 SnapBuildXidSetCatalogChanges().

Previously, when decoding the commit record of the transaction, we
mark both top-level transaction and its subtransactions as containing
catalog changes and assign the subtransactions to the top-level
transaction. However, if the subtransacitons have invalidation
messages, we missed executing them when forgetting the
transactions. In commit 272248a0c1 where we introduced
SnapBuildXidSetCatalogChanges(), the reason why we assigned them is
just to avoid the assertion failure in AssertTXNLsnOrder() as they
have the same LSN. Now that with commit XXX we skip this assertion
check until we reach the LSN at we start decoding the contents of the
transaciton, there is no reason for that anymore.

SnapBuildXidSetCatalogChanges() was introduced in 15 or older but this
bug doesn't exist in branches prior to 14 since we don't add
invalidation messages to subtransactions. We decided to backpatch
through 11 for consistency but don't for 10 since its final release
will come soon.

Reported-by: Osumi Takamichi
Author: Masahiko Sawada
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/TYAPR01MB58660803BCAA7849C8584AA4F57E9%40TYAPR01MB5866.jpnprd01.prod.outlook.com
Backpatch: Backpatch-through: 11
---
 .../expected/catalog_change_snapshot.out      | 45 +++++++++++++++++++
 .../specs/catalog_change_snapshot.spec        |  8 ++++
 src/backend/replication/logical/snapbuild.c   |  7 +--
 3 files changed, 57 insertions(+), 3 deletions(-)

diff --git a/contrib/test_decoding/expected/catalog_change_snapshot.out b/contrib/test_decoding/expected/catalog_change_snapshot.out
index 1d75cf5af0..b33e49c0b1 100644
--- a/contrib/test_decoding/expected/catalog_change_snapshot.out
+++ b/contrib/test_decoding/expected/catalog_change_snapshot.out
@@ -87,3 +87,48 @@ COMMIT
 stop    
 (1 row)
 
+
+starting permutation: s0_init s0_begin s0_savepoint s0_insert s1_checkpoint s1_get_changes s0_truncate s0_commit s0_begin s0_insert s1_checkpoint s1_get_changes s0_commit s1_get_changes
+step s0_init: SELECT 'init' FROM pg_create_logical_replication_slot('isolation_slot', 'test_decoding');
+?column?
+--------
+init    
+(1 row)
+
+step s0_begin: BEGIN;
+step s0_savepoint: SAVEPOINT sp1;
+step s0_insert: INSERT INTO tbl1 VALUES (1);
+step s1_checkpoint: CHECKPOINT;
+step s1_get_changes: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'skip-empty-xacts', '1', 'include-xids', '0');
+data
+----
+(0 rows)
+
+step s0_truncate: TRUNCATE tbl1;
+step s0_commit: COMMIT;
+step s0_begin: BEGIN;
+step s0_insert: INSERT INTO tbl1 VALUES (1);
+step s1_checkpoint: CHECKPOINT;
+step s1_get_changes: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'skip-empty-xacts', '1', 'include-xids', '0');
+data                                                         
+-------------------------------------------------------------
+BEGIN                                                        
+table public.tbl1: INSERT: val1[integer]:1 val2[integer]:null
+table public.tbl1: TRUNCATE: (no-flags)                      
+COMMIT                                                       
+(4 rows)
+
+step s0_commit: COMMIT;
+step s1_get_changes: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'skip-empty-xacts', '1', 'include-xids', '0');
+data                                                         
+-------------------------------------------------------------
+BEGIN                                                        
+table public.tbl1: INSERT: val1[integer]:1 val2[integer]:null
+COMMIT                                                       
+(3 rows)
+
+?column?
+--------
+stop    
+(1 row)
+
diff --git a/contrib/test_decoding/specs/catalog_change_snapshot.spec b/contrib/test_decoding/specs/catalog_change_snapshot.spec
index 2ad1edeaa8..b3ccb9e0e9 100644
--- a/contrib/test_decoding/specs/catalog_change_snapshot.spec
+++ b/contrib/test_decoding/specs/catalog_change_snapshot.spec
@@ -53,3 +53,11 @@ permutation "s0_init" "s0_begin" "s0_savepoint" "s0_truncate" "s1_checkpoint" "s
 # transaction to do timetravel since one of its subtransactions has been marked as
 # containing catalog changes.
 permutation "s0_init" "s0_begin" "s0_savepoint" "s0_insert" "s1_checkpoint" "s1_get_changes" "s0_insert2" "s0_commit" "s0_begin" "s0_insert" "s1_checkpoint" "s1_get_changes" "s0_commit" "s1_get_changes"
+
+# The last decoding restarts from the first checkpoint, and add invalidation messages
+# generated by "s0_truncate" to the subtransaction. When decoding the commit record of
+# the top-level transaction, we mark both top-level transaction and its subtransactions
+# as containing catalog changes. However, we check if we don't create the association
+# between top-level and subtransactions at this time. Otherwise, we miss executing
+# invalidation messages when forgetting the transaction.
+permutation "s0_init" "s0_begin" "s0_savepoint" "s0_insert" "s1_checkpoint" "s1_get_changes" "s0_truncate" "s0_commit" "s0_begin" "s0_insert" "s1_checkpoint" "s1_get_changes" "s0_commit" "s1_get_changes"
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index dfe9d017f2..f3f5aba6a3 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -2113,10 +2113,11 @@ SnapBuildXidSetCatalogChanges(SnapBuild *builder, TransactionId xid, int subxcnt
 	{
 		int		i;
 
+		/*
+		 * We will assign subtransactions to the top transaction before
+		 * replaying the contents of the transaction.
+		 */
 		for (i = 0; i < subxcnt; i++)
-		{
-			ReorderBufferAssignChild(builder->reorder, xid, subxacts[i], lsn);
 			ReorderBufferXidSetCatalogChanges(builder->reorder, subxacts[i], lsn);
-		}
 	}
 }
-- 
2.31.1

