Thread: Re: Proposal: Progressive explain

hi.

[48/208] Compiling C object
contrib/postgres_fdw/postgres_fdw.so.p/postgres_fdw.c.o
FAILED: contrib/postgres_fdw/postgres_fdw.so.p/postgres_fdw.c.o
/usr/local/gcc-14.1.0/bin/gcc-14.1.0
-Icontrib/postgres_fdw/postgres_fdw.so.p -Isrc/include
-I../../Desktop/pg_src/src5/postgres/src/include
-Isrc/interfaces/libpq
-I../../Desktop/pg_src/src5/postgres/src/interfaces/libpq
-I/usr/include/libxml2 -fdiagnostics-color=always --coverage
-D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Werror -g
-fno-strict-aliasing -fwrapv -fexcess-precision=standard -D_GNU_SOURCE
-Wmissing-prototypes -Wpointer-arith -Werror=vla -Wendif-labels
-Wmissing-format-attribute -Wimplicit-fallthrough=3
-Wcast-function-type -Wshadow=compatible-local -Wformat-security
-Wdeclaration-after-statement -Wmissing-variable-declarations
-Wno-format-truncation -Wno-stringop-truncation -Wunused-variable
-Wuninitialized -Werror=maybe-uninitialized -Wreturn-type
-DWRITE_READ_PARSE_PLAN_TREES -DCOPY_PARSE_PLAN_TREES
-DREALLOCATE_BITMAPSETS -DLOCK_DEBUG -DRELCACHE_FORCE_RELEASE
-DENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS
-DRAW_EXPRESSION_COVERAGE_TEST -fno-omit-frame-pointer -fPIC -pthread
-fvisibility=hidden -MD -MQ
contrib/postgres_fdw/postgres_fdw.so.p/postgres_fdw.c.o -MF
contrib/postgres_fdw/postgres_fdw.so.p/postgres_fdw.c.o.d -o
contrib/postgres_fdw/postgres_fdw.so.p/postgres_fdw.c.o -c
../../Desktop/pg_src/src5/postgres/contrib/postgres_fdw/postgres_fdw.c
In file included from
../../Desktop/pg_src/src5/postgres/contrib/postgres_fdw/postgres_fdw.c:22:
../../Desktop/pg_src/src5/postgres/src/include/commands/explain.h:86:9:
error: unknown type name ‘TimestampTz’
   86 |         TimestampTz last_explain;
      |         ^~~~~~~~~~~
[58/188] Linking target contrib/sslinfo/sslinfo.so
ninja: build stopped: subcommand failed.

compile failed. the above is the error message.

hi.


all the newly added GUC
progressive_explain;
progressive_explain_verbose;
progressive_explain_settings;
progressive_explain_interval;
progressive_explain_output_size;
progressive_explain_format;
progressive_explain_sample_rate;
also need to add to postgresql.conf.sample?


in doc/src/sgml/monitoring.sgml, we also need add
view pg_stat_progress_explain
to the section
<table id="monitoring-stats-dynamic-views-table">
<title>Dynamic Statistics Views</title>
(Table 27.1. Dynamic Statistics Views)

pg_stat_progress_explain.explain will be truncated after 4096 byte.
(default value of progressive_explain_output_size)
so if the progressive_explain_format is json,
and the plan is bigger (imagine two partitioned tables joined
together, each having many partitions)
the column "explain" text may not be a valid json.
Should we be concerned about this?


I don't really understand the actual usage of
pg_stat_progress_explain.explain_count.
Other column usage makes sense to me.
Can you share your idea why we need this column?


select name, category from pg_settings
where category =  'Query Tuning / Planner Method Configuration';
you will see that in config_group as QUERY_TUNING_METHOD
all the GUC names generally begin with "enable".
all the GUC names begin with "progressive" set the config_group as
QUERY_TUNING_METHOD
may not be appropriate? also it is not related to query tuning.


#include "utils/backend_status.h"
#include "storage/procarray.h"
#include "executor/spi.h"
#include "utils/guc.h"

src/backend/commands/explain.c
the header generally should be sorted in alphabetical ascending order.
apply the order to ipci.c, execMain.c, execProcnode.c

            else
                /* Node in progress */
            if (es->progressive && planstate ==
planstate->state->progressive_explain_current_node)
                appendStringInfo(es->str,
                                 " (actual rows=%.0f loops=%.0f) (current)",
                                 rows, nloops);
            else
                appendStringInfo(es->str,
                                 " (actual rows=%.0f loops=%.0f)",
                                 rows, nloops);

the above part in src/backend/commands/explain.c ExplainNode, the
indentation looks wrong to me.