From 627c79a1e87d9ec4a8a8a0c5be8564ba74e221ea Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Tue, 22 Feb 2022 10:23:49 +0900
Subject: [PATCH] Add compute_query_id = regress
"regress" is a new mode added to compute_query_id aimed at facilitating
regression testing when a module computing query IDs is loaded into the
backend, like pg_stat_statements. It works the same way as "auto",
meaning that query IDs are computed if a module enables it, except that
query IDs are hidden in EXPLAIN outputs to ensure regression output
stability.
Like any GUCs of the kind (force_parallel_mode, etc.), this new
configuration can be added to an instance's postgresql.conf, or just
passed down with PGOPTIONS at command level. compute_query_id uses an
enum for its set of option values, meaning that this addition ensures
ABI compatibility.
Using this new configuration mode allows installcheck-world to pass when
running the tests on an instance with pg_stat_statements enabled,
stabilizing the test output while checking the paths doing query ID
computations.
Reported-by: Anton Melnikov
Reviewed-by: Julien Rouhaud
Discussion: https://postgr.es/m/1634283396.372373993@f75.i.mail.ru
Discussion: https://postgr.es/m/YgHlxgc/OimuPYhH@paquier.xyz
Backpatch-through: 14
---
doc/src/sgml/config.sgml | 7 +++++--
src/backend/commands/explain.c | 8 +++++++-
src/backend/utils/misc/guc.c | 1 +
src/include/utils/queryjumble.h | 3 ++-
4 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index d046614d765..18cf72db051 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -7680,9 +7680,12 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
method is not acceptable. In this case, in-core computation
must be always disabled.
Valid values are <literal>off</literal> (always disabled),
- <literal>on</literal> (always enabled) and <literal>auto</literal>,
+ <literal>on</literal> (always enabled), <literal>auto</literal>,
which lets modules such as <xref linkend="pgstatstatements"/>
- automatically enable it.
+ automatically enable it, and <literal>regress</literal> which
+ has the same effect as <literal>auto</literal>, except that the
+ query identifier is hidden in the <literal>EXPLAIN</literal> output
+ to facilitate automated regression testing.
The default is <literal>auto</literal>.
</para>
<note>
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 81a227d8b8d..70551522dac 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -604,7 +604,13 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
/* Create textual dump of plan tree */
ExplainPrintPlan(es, queryDesc);
- if (es->verbose && plannedstmt->queryId != UINT64CONST(0))
+ /*
+ * COMPUTE_QUERY_ID_REGRESS means COMPUTE_QUERY_ID_AUTO, but we don't show
+ * the queryid in any of the EXPLAIN plans to keep stable the results
+ * generated by regression test suites.
+ */
+ if (es->verbose && plannedstmt->queryId != UINT64CONST(0) &&
+ compute_query_id != COMPUTE_QUERY_ID_REGRESS)
{
/*
* Output the queryid as an int64 rather than a uint64 so we match
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 6652a60ec31..b1d8317aa22 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -409,6 +409,7 @@ static const struct config_enum_entry backslash_quote_options[] = {
*/
static const struct config_enum_entry compute_query_id_options[] = {
{"auto", COMPUTE_QUERY_ID_AUTO, false},
+ {"regress", COMPUTE_QUERY_ID_REGRESS, false},
{"on", COMPUTE_QUERY_ID_ON, false},
{"off", COMPUTE_QUERY_ID_OFF, false},
{"true", COMPUTE_QUERY_ID_ON, true},
diff --git a/src/include/utils/queryjumble.h b/src/include/utils/queryjumble.h
index 7af6652f3e0..af5d999b9cb 100644
--- a/src/include/utils/queryjumble.h
+++ b/src/include/utils/queryjumble.h
@@ -57,7 +57,8 @@ enum ComputeQueryIdType
{
COMPUTE_QUERY_ID_OFF,
COMPUTE_QUERY_ID_ON,
- COMPUTE_QUERY_ID_AUTO
+ COMPUTE_QUERY_ID_AUTO,
+ COMPUTE_QUERY_ID_REGRESS
};
/* GUC parameters */