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The original syntax made it difficult to add options without making them into reserved words. This change parenthesizes the options to avoid that problem, and makes provision for an explicit (and perhaps non-Boolean) value for each option. The original syntax is still supported, but only for the two original options ANALYZE and VERBOSE. As a test case, add a COSTS option that can suppress the planner cost estimates. This may be useful for including EXPLAIN output in the regression tests, which are otherwise unable to cope with cross-platform variations in cost estimates. Robert Haas
230 lines
5.5 KiB
C
230 lines
5.5 KiB
C
/*-------------------------------------------------------------------------
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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) 2008-2009, 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 1.6 2009/07/26 23:34:17 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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/* GUC variables */
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static int auto_explain_log_min_duration = -1; /* msec or -1 */
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static bool auto_explain_log_analyze = false;
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static bool auto_explain_log_verbose = false;
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static bool auto_explain_log_nested_statements = 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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(auto_explain_log_min_duration >= 0 && \
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(nesting_level == 0 || auto_explain_log_nested_statements))
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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("auto_explain.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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&auto_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("auto_explain.log_analyze",
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"Use EXPLAIN ANALYZE for plan logging.",
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NULL,
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&auto_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("auto_explain.log_verbose",
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"Use EXPLAIN VERBOSE for plan logging.",
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NULL,
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&auto_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("auto_explain.log_nested_statements",
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"Log nested statements.",
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NULL,
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&auto_explain_log_nested_statements,
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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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EmitWarningsOnPlaceholders("auto_explain");
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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 (auto_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 the
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* space is allocated in the per-query context so it will go away at
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* 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 several
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* 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 >= auto_explain_log_min_duration)
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{
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ExplainState es;
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ExplainInitState(&es);
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es.analyze = (queryDesc->doInstrument && auto_explain_log_analyze);
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es.verbose = auto_explain_log_verbose;
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ExplainPrintPlan(&es, queryDesc);
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/* Remove last line break */
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if (es.str->len > 0 && es.str->data[es.str->len - 1] == '\n')
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es.str->data[--es.str->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, es.str->data)));
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pfree(es.str->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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