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8e166e164c
The folly of the previous arrangement was just demonstrated: there's no convenient way to add fields to ExplainState without breaking ABI, even if callers have no need to touch those fields. Since we might well need to do that again someday in back branches, let's change things so that only explain.c has to have sizeof(ExplainState) compiled into it. This costs one extra palloc() per EXPLAIN operation, which is surely pretty negligible.
344 lines
8.3 KiB
C
344 lines
8.3 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) 2008-2015, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/auto_explain/auto_explain.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <limits.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_buffers = false;
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static bool auto_explain_log_triggers = false;
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static bool auto_explain_log_timing = true;
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static int auto_explain_log_format = EXPLAIN_FORMAT_TEXT;
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static bool auto_explain_log_nested_statements = false;
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static const struct config_enum_entry format_options[] = {
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{"text", EXPLAIN_FORMAT_TEXT, false},
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{"xml", EXPLAIN_FORMAT_XML, false},
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{"json", EXPLAIN_FORMAT_JSON, false},
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{"yaml", EXPLAIN_FORMAT_YAML, false},
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{NULL, 0, false}
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};
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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 ExecutorFinish_hook_type prev_ExecutorFinish = 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_ExecutorFinish(QueryDesc *queryDesc);
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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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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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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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NULL);
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DefineCustomBoolVariable("auto_explain.log_buffers",
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"Log buffers usage.",
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NULL,
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&auto_explain_log_buffers,
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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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NULL);
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DefineCustomBoolVariable("auto_explain.log_triggers",
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"Include trigger statistics in plans.",
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"This has no effect unless log_analyze is also set.",
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&auto_explain_log_triggers,
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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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NULL);
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DefineCustomEnumVariable("auto_explain.log_format",
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"EXPLAIN format to be used for plan logging.",
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NULL,
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&auto_explain_log_format,
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EXPLAIN_FORMAT_TEXT,
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format_options,
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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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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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NULL);
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DefineCustomBoolVariable("auto_explain.log_timing",
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"Collect timing data, not just row counts.",
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NULL,
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&auto_explain_log_timing,
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true,
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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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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_ExecutorFinish = ExecutorFinish_hook;
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ExecutorFinish_hook = explain_ExecutorFinish;
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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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ExecutorFinish_hook = prev_ExecutorFinish;
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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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static 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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{
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if (auto_explain_log_timing)
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queryDesc->instrument_options |= INSTRUMENT_TIMER;
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else
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queryDesc->instrument_options |= INSTRUMENT_ROWS;
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if (auto_explain_log_buffers)
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queryDesc->instrument_options |= INSTRUMENT_BUFFERS;
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}
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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, INSTRUMENT_ALL);
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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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static 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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* ExecutorFinish hook: all we need do is track nesting depth
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*/
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static void
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explain_ExecutorFinish(QueryDesc *queryDesc)
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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_ExecutorFinish)
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prev_ExecutorFinish(queryDesc);
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else
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standard_ExecutorFinish(queryDesc);
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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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static 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 = NewExplainState();
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es->analyze = (queryDesc->instrument_options && auto_explain_log_analyze);
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es->verbose = auto_explain_log_verbose;
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es->buffers = (es->analyze && auto_explain_log_buffers);
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es->timing = (es->analyze && auto_explain_log_timing);
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es->summary = es->analyze;
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es->format = auto_explain_log_format;
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ExplainBeginOutput(es);
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ExplainQueryText(es, queryDesc);
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ExplainPrintPlan(es, queryDesc);
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if (es->analyze && auto_explain_log_triggers)
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ExplainPrintTriggers(es, queryDesc);
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ExplainEndOutput(es);
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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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/* Fix JSON to output an object */
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if (auto_explain_log_format == EXPLAIN_FORMAT_JSON)
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{
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es->str->data[0] = '{';
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es->str->data[es->str->len - 1] = '}';
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}
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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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errhidestmt(true)));
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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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