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Add auto-explain contrib module for automatic logging of the plans of
slow-running queries. Takahiro Itagaki
1 parent 31ec957 commit e125e28

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7 files changed

+429
-3
lines changed

7 files changed

+429
-3
lines changed

‎contrib/Makefile

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@@ -1,11 +1,12 @@
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# $PostgreSQL: pgsql/contrib/Makefile,v 1.84 2008/07/29 18:31:20 tgl Exp $
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# $PostgreSQL: pgsql/contrib/Makefile,v 1.85 2008/11/19 02:59:28 tgl Exp $
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subdir = contrib
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top_builddir = ..
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include $(top_builddir)/src/Makefile.global
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WANTED_DIRS = \
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adminpack \
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auto_explain \
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btree_gist \
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chkpass \
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citext \

‎contrib/README

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@@ -28,6 +28,10 @@ adminpack -
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File and log manipulation routines, used by pgAdmin
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by Dave Page <dpage@vale-housing.co.uk>
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auto_explain -
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Log EXPLAIN output for long-running queries
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by Takahiro Itagaki <itagaki.takahiro@oss.ntt.co.jp>
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btree_gist -
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Support for emulating BTREE indexing in GiST
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by Oleg Bartunov <oleg@sai.msu.su> and Teodor Sigaev <teodor@sigaev.ru>

‎contrib/auto_explain/Makefile

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# $PostgreSQL: pgsql/contrib/auto_explain/Makefile,v 1.1 2008/11/19 02:59:28 tgl Exp $
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MODULE_big = auto_explain
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OBJS = auto_explain.o
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ifdef USE_PGXS
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PG_CONFIG = pg_config
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PGXS := $(shell $(PG_CONFIG) --pgxs)
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include $(PGXS)
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else
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subdir = contrib/auto_explain
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top_builddir = ../..
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include $(top_builddir)/src/Makefile.global
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include $(top_srcdir)/contrib/contrib-global.mk
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endif

‎contrib/auto_explain/auto_explain.c

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/*-------------------------------------------------------------------------
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*
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* auto_explain.c
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*
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*
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* Copyright (c) 2008, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/contrib/auto_explain/auto_explain.c,v 1.1 2008/11/19 02:59:28 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "commands/explain.h"
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#include "executor/instrument.h"
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#include "utils/guc.h"
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PG_MODULE_MAGIC;
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#define GUCNAME(name) ("explain." name)
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/* GUC variables */
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static int explain_log_min_duration = -1; /* msec or -1 */
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static bool explain_log_analyze = false;
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static bool explain_log_verbose = false;
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static bool explain_log_nested = false;
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/* Current nesting depth of ExecutorRun calls */
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static int nesting_level = 0;
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/* Saved hook values in case of unload */
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static ExecutorStart_hook_type prev_ExecutorStart = NULL;
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static ExecutorRun_hook_type prev_ExecutorRun = NULL;
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static ExecutorEnd_hook_type prev_ExecutorEnd = NULL;
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#define auto_explain_enabled() \
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(explain_log_min_duration >= 0 && \
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(nesting_level == 0 || explain_log_nested))
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void _PG_init(void);
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void _PG_fini(void);
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static void explain_ExecutorStart(QueryDesc *queryDesc, int eflags);
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static void explain_ExecutorRun(QueryDesc *queryDesc,
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ScanDirection direction,
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long count);
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static void explain_ExecutorEnd(QueryDesc *queryDesc);
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/*
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* Module load callback
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*/
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void
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_PG_init(void)
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{
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/* Define custom GUC variables. */
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DefineCustomIntVariable(GUCNAME("log_min_duration"),
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"Sets the minimum execution time above which plans will be logged.",
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"Zero prints all plans. -1 turns this feature off.",
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&explain_log_min_duration,
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-1,
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-1, INT_MAX / 1000,
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PGC_SUSET,
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GUC_UNIT_MS,
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NULL,
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NULL);
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DefineCustomBoolVariable(GUCNAME("log_analyze"),
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"Use EXPLAIN ANALYZE for plan logging.",
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NULL,
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&explain_log_analyze,
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false,
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PGC_SUSET,
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0,
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NULL,
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NULL);
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DefineCustomBoolVariable(GUCNAME("log_verbose"),
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"Use EXPLAIN VERBOSE for plan logging.",
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NULL,
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&explain_log_verbose,
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false,
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PGC_SUSET,
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0,
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NULL,
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NULL);
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DefineCustomBoolVariable(GUCNAME("log_nested_statements"),
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"Log nested statements.",
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NULL,
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&explain_log_nested,
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false,
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PGC_SUSET,
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0,
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NULL,
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NULL);
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/* Install hooks. */
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prev_ExecutorStart = ExecutorStart_hook;
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ExecutorStart_hook = explain_ExecutorStart;
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prev_ExecutorRun = ExecutorRun_hook;
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ExecutorRun_hook = explain_ExecutorRun;
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prev_ExecutorEnd = ExecutorEnd_hook;
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ExecutorEnd_hook = explain_ExecutorEnd;
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}
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/*
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* Module unload callback
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*/
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void
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_PG_fini(void)
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{
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/* Uninstall hooks. */
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ExecutorStart_hook = prev_ExecutorStart;
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ExecutorRun_hook = prev_ExecutorRun;
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ExecutorEnd_hook = prev_ExecutorEnd;
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}
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/*
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* ExecutorStart hook: start up logging if needed
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*/
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void
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explain_ExecutorStart(QueryDesc *queryDesc, int eflags)
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{
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if (auto_explain_enabled())
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{
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/* Enable per-node instrumentation iff log_analyze is required. */
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if (explain_log_analyze && (eflags & EXEC_FLAG_EXPLAIN_ONLY) == 0)
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queryDesc->doInstrument = true;
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}
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if (prev_ExecutorStart)
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prev_ExecutorStart(queryDesc, eflags);
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else
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standard_ExecutorStart(queryDesc, eflags);
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if (auto_explain_enabled())
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{
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/*
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* Set up to track total elapsed time in ExecutorRun. Make sure
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* the space is allocated in the per-query context so it will go
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* away at ExecutorEnd.
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*/
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if (queryDesc->totaltime == NULL)
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{
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MemoryContext oldcxt;
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oldcxt = MemoryContextSwitchTo(queryDesc->estate->es_query_cxt);
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queryDesc->totaltime = InstrAlloc(1);
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MemoryContextSwitchTo(oldcxt);
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}
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}
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}
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/*
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* ExecutorRun hook: all we need do is track nesting depth
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*/
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void
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explain_ExecutorRun(QueryDesc *queryDesc, ScanDirection direction, long count)
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{
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nesting_level++;
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PG_TRY();
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{
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if (prev_ExecutorRun)
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prev_ExecutorRun(queryDesc, direction, count);
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else
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standard_ExecutorRun(queryDesc, direction, count);
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nesting_level--;
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}
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PG_CATCH();
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{
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nesting_level--;
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PG_RE_THROW();
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}
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PG_END_TRY();
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}
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/*
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* ExecutorEnd hook: log results if needed
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*/
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void
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explain_ExecutorEnd(QueryDesc *queryDesc)
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{
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if (queryDesc->totaltime && auto_explain_enabled())
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{
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double msec;
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/*
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* Make sure stats accumulation is done. (Note: it's okay if
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* several levels of hook all do this.)
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*/
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InstrEndLoop(queryDesc->totaltime);
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/* Log plan if duration is exceeded. */
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msec = queryDesc->totaltime->total * 1000.0;
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if (msec >= explain_log_min_duration)
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{
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StringInfoData buf;
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initStringInfo(&buf);
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ExplainPrintPlan(&buf, queryDesc,
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queryDesc->doInstrument && explain_log_analyze,
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explain_log_verbose);
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/* Remove last line break */
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if (buf.len > 0 && buf.data[buf.len - 1] == '\n')
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buf.data[--buf.len] = '\0';
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/*
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* Note: we rely on the existing logging of context or
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* debug_query_string to identify just which statement is being
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* reported. This isn't ideal but trying to do it here would
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* often result in duplication.
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*/
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ereport(LOG,
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(errmsg("duration: %.3f ms plan:\n%s",
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msec, buf.data)));
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pfree(buf.data);
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}
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}
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if (prev_ExecutorEnd)
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prev_ExecutorEnd(queryDesc);
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else
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standard_ExecutorEnd(queryDesc);
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}

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