postgresql/contrib/auto_explain/auto_explain.c
Tom Lane 382ceffdf7 Phase 3 of pgindent updates.
Don't move parenthesized lines to the left, even if that means they
flow past the right margin.

By default, BSD indent lines up statement continuation lines that are
within parentheses so that they start just to the right of the preceding
left parenthesis.  However, traditionally, if that resulted in the
continuation line extending to the right of the desired right margin,
then indent would push it left just far enough to not overrun the margin,
if it could do so without making the continuation line start to the left of
the current statement indent.  That makes for a weird mix of indentations
unless one has been completely rigid about never violating the 80-column
limit.

This behavior has been pretty universally panned by Postgres developers.
Hence, disable it with indent's new -lpl switch, so that parenthesized
lines are always lined up with the preceding left paren.

This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.

Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
2017-06-21 15:35:54 -04:00

370 lines
9.2 KiB
C

/*-------------------------------------------------------------------------
*
* auto_explain.c
*
*
* Copyright (c) 2008-2017, PostgreSQL Global Development Group
*
* IDENTIFICATION
* contrib/auto_explain/auto_explain.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <limits.h>
#include "commands/explain.h"
#include "executor/instrument.h"
#include "utils/guc.h"
PG_MODULE_MAGIC;
/* GUC variables */
static int auto_explain_log_min_duration = -1; /* msec or -1 */
static bool auto_explain_log_analyze = false;
static bool auto_explain_log_verbose = false;
static bool auto_explain_log_buffers = false;
static bool auto_explain_log_triggers = false;
static bool auto_explain_log_timing = true;
static int auto_explain_log_format = EXPLAIN_FORMAT_TEXT;
static bool auto_explain_log_nested_statements = false;
static double auto_explain_sample_rate = 1;
static const struct config_enum_entry format_options[] = {
{"text", EXPLAIN_FORMAT_TEXT, false},
{"xml", EXPLAIN_FORMAT_XML, false},
{"json", EXPLAIN_FORMAT_JSON, false},
{"yaml", EXPLAIN_FORMAT_YAML, false},
{NULL, 0, false}
};
/* Current nesting depth of ExecutorRun calls */
static int nesting_level = 0;
/* Saved hook values in case of unload */
static ExecutorStart_hook_type prev_ExecutorStart = NULL;
static ExecutorRun_hook_type prev_ExecutorRun = NULL;
static ExecutorFinish_hook_type prev_ExecutorFinish = NULL;
static ExecutorEnd_hook_type prev_ExecutorEnd = NULL;
/* Is the current query sampled, per backend */
static bool current_query_sampled = true;
#define auto_explain_enabled() \
(auto_explain_log_min_duration >= 0 && \
(nesting_level == 0 || auto_explain_log_nested_statements))
void _PG_init(void);
void _PG_fini(void);
static void explain_ExecutorStart(QueryDesc *queryDesc, int eflags);
static void explain_ExecutorRun(QueryDesc *queryDesc,
ScanDirection direction,
uint64 count, bool execute_once);
static void explain_ExecutorFinish(QueryDesc *queryDesc);
static void explain_ExecutorEnd(QueryDesc *queryDesc);
/*
* Module load callback
*/
void
_PG_init(void)
{
/* Define custom GUC variables. */
DefineCustomIntVariable("auto_explain.log_min_duration",
"Sets the minimum execution time above which plans will be logged.",
"Zero prints all plans. -1 turns this feature off.",
&auto_explain_log_min_duration,
-1,
-1, INT_MAX / 1000,
PGC_SUSET,
GUC_UNIT_MS,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("auto_explain.log_analyze",
"Use EXPLAIN ANALYZE for plan logging.",
NULL,
&auto_explain_log_analyze,
false,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("auto_explain.log_verbose",
"Use EXPLAIN VERBOSE for plan logging.",
NULL,
&auto_explain_log_verbose,
false,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("auto_explain.log_buffers",
"Log buffers usage.",
NULL,
&auto_explain_log_buffers,
false,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("auto_explain.log_triggers",
"Include trigger statistics in plans.",
"This has no effect unless log_analyze is also set.",
&auto_explain_log_triggers,
false,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomEnumVariable("auto_explain.log_format",
"EXPLAIN format to be used for plan logging.",
NULL,
&auto_explain_log_format,
EXPLAIN_FORMAT_TEXT,
format_options,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("auto_explain.log_nested_statements",
"Log nested statements.",
NULL,
&auto_explain_log_nested_statements,
false,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("auto_explain.log_timing",
"Collect timing data, not just row counts.",
NULL,
&auto_explain_log_timing,
true,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomRealVariable("auto_explain.sample_rate",
"Fraction of queries to process.",
NULL,
&auto_explain_sample_rate,
1.0,
0.0,
1.0,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
EmitWarningsOnPlaceholders("auto_explain");
/* Install hooks. */
prev_ExecutorStart = ExecutorStart_hook;
ExecutorStart_hook = explain_ExecutorStart;
prev_ExecutorRun = ExecutorRun_hook;
ExecutorRun_hook = explain_ExecutorRun;
prev_ExecutorFinish = ExecutorFinish_hook;
ExecutorFinish_hook = explain_ExecutorFinish;
prev_ExecutorEnd = ExecutorEnd_hook;
ExecutorEnd_hook = explain_ExecutorEnd;
}
/*
* Module unload callback
*/
void
_PG_fini(void)
{
/* Uninstall hooks. */
ExecutorStart_hook = prev_ExecutorStart;
ExecutorRun_hook = prev_ExecutorRun;
ExecutorFinish_hook = prev_ExecutorFinish;
ExecutorEnd_hook = prev_ExecutorEnd;
}
/*
* ExecutorStart hook: start up logging if needed
*/
static void
explain_ExecutorStart(QueryDesc *queryDesc, int eflags)
{
/*
* For rate sampling, randomly choose top-level statement. Either all
* nested statements will be explained or none will.
*/
if (auto_explain_log_min_duration >= 0 && nesting_level == 0)
current_query_sampled = (random() < auto_explain_sample_rate *
MAX_RANDOM_VALUE);
if (auto_explain_enabled() && current_query_sampled)
{
/* Enable per-node instrumentation iff log_analyze is required. */
if (auto_explain_log_analyze && (eflags & EXEC_FLAG_EXPLAIN_ONLY) == 0)
{
if (auto_explain_log_timing)
queryDesc->instrument_options |= INSTRUMENT_TIMER;
else
queryDesc->instrument_options |= INSTRUMENT_ROWS;
if (auto_explain_log_buffers)
queryDesc->instrument_options |= INSTRUMENT_BUFFERS;
}
}
if (prev_ExecutorStart)
prev_ExecutorStart(queryDesc, eflags);
else
standard_ExecutorStart(queryDesc, eflags);
if (auto_explain_enabled() && current_query_sampled)
{
/*
* Set up to track total elapsed time in ExecutorRun. Make sure the
* space is allocated in the per-query context so it will go away at
* ExecutorEnd.
*/
if (queryDesc->totaltime == NULL)
{
MemoryContext oldcxt;
oldcxt = MemoryContextSwitchTo(queryDesc->estate->es_query_cxt);
queryDesc->totaltime = InstrAlloc(1, INSTRUMENT_ALL);
MemoryContextSwitchTo(oldcxt);
}
}
}
/*
* ExecutorRun hook: all we need do is track nesting depth
*/
static void
explain_ExecutorRun(QueryDesc *queryDesc, ScanDirection direction,
uint64 count, bool execute_once)
{
nesting_level++;
PG_TRY();
{
if (prev_ExecutorRun)
prev_ExecutorRun(queryDesc, direction, count, execute_once);
else
standard_ExecutorRun(queryDesc, direction, count, execute_once);
nesting_level--;
}
PG_CATCH();
{
nesting_level--;
PG_RE_THROW();
}
PG_END_TRY();
}
/*
* ExecutorFinish hook: all we need do is track nesting depth
*/
static void
explain_ExecutorFinish(QueryDesc *queryDesc)
{
nesting_level++;
PG_TRY();
{
if (prev_ExecutorFinish)
prev_ExecutorFinish(queryDesc);
else
standard_ExecutorFinish(queryDesc);
nesting_level--;
}
PG_CATCH();
{
nesting_level--;
PG_RE_THROW();
}
PG_END_TRY();
}
/*
* ExecutorEnd hook: log results if needed
*/
static void
explain_ExecutorEnd(QueryDesc *queryDesc)
{
if (queryDesc->totaltime && auto_explain_enabled() && current_query_sampled)
{
double msec;
/*
* Make sure stats accumulation is done. (Note: it's okay if several
* levels of hook all do this.)
*/
InstrEndLoop(queryDesc->totaltime);
/* Log plan if duration is exceeded. */
msec = queryDesc->totaltime->total * 1000.0;
if (msec >= auto_explain_log_min_duration)
{
ExplainState *es = NewExplainState();
es->analyze = (queryDesc->instrument_options && auto_explain_log_analyze);
es->verbose = auto_explain_log_verbose;
es->buffers = (es->analyze && auto_explain_log_buffers);
es->timing = (es->analyze && auto_explain_log_timing);
es->summary = es->analyze;
es->format = auto_explain_log_format;
ExplainBeginOutput(es);
ExplainQueryText(es, queryDesc);
ExplainPrintPlan(es, queryDesc);
if (es->analyze && auto_explain_log_triggers)
ExplainPrintTriggers(es, queryDesc);
ExplainEndOutput(es);
/* Remove last line break */
if (es->str->len > 0 && es->str->data[es->str->len - 1] == '\n')
es->str->data[--es->str->len] = '\0';
/* Fix JSON to output an object */
if (auto_explain_log_format == EXPLAIN_FORMAT_JSON)
{
es->str->data[0] = '{';
es->str->data[es->str->len - 1] = '}';
}
/*
* Note: we rely on the existing logging of context or
* debug_query_string to identify just which statement is being
* reported. This isn't ideal but trying to do it here would
* often result in duplication.
*/
ereport(LOG,
(errmsg("duration: %.3f ms plan:\n%s",
msec, es->str->data),
errhidestmt(true)));
pfree(es->str->data);
}
}
if (prev_ExecutorEnd)
prev_ExecutorEnd(queryDesc);
else
standard_ExecutorEnd(queryDesc);
}