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EXPLAIN ANALYZE feature to measure and show actual runtimes and tuple

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counts alongside the planner's estimates.  By Martijn van Oosterhout,
with some further work by Tom Lane.
This commit is contained in:
Tom Lane
2001-09-18 01:59:07 +00:00
parent 27d2890b87
commit 89fa551808
18 changed files with 413 additions and 87 deletions
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82
src/backend/commands/explain.c
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@ -5,18 +5,20 @@
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994-5, Regents of the University of California
*
* $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.65 2001/03/22 03:59:22 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.66 2001/09/18 01:59:06 tgl Exp $
*
*/
#include "postgres.h"
#include "commands/explain.h"
#include "executor/instrument.h"
#include "lib/stringinfo.h"
#include "nodes/print.h"
#include "optimizer/planner.h"
#include "parser/parsetree.h"
#include "rewrite/rewriteHandler.h"
#include "tcop/pquery.h"
#include "utils/relcache.h"
typedef struct ExplainState
@ -28,8 +30,8 @@ typedef struct ExplainState
List *rtable; /* range table */
} ExplainState;
static char *Explain_PlanToString(Plan *plan, ExplainState *es);
static void ExplainOneQuery(Query *query, bool verbose, CommandDest dest);
static StringInfo Explain_PlanToString(Plan *plan, ExplainState *es);
static void ExplainOneQuery(Query *query, bool verbose, bool analyze, CommandDest dest);
/* Convert a null string pointer into "<>" */
#define stringStringInfo(s) (((s) == NULL) ? "<>" : (s))
@ -41,7 +43,7 @@ static void ExplainOneQuery(Query *query, bool verbose, CommandDest dest);
*
*/
void
ExplainQuery(Query *query, bool verbose, CommandDest dest)
ExplainQuery(Query *query, bool verbose, bool analyze, CommandDest dest)
{
List *rewritten;
List *l;
@ -73,7 +75,7 @@ ExplainQuery(Query *query, bool verbose, CommandDest dest)
/* Explain every plan */
foreach(l, rewritten)
ExplainOneQuery(lfirst(l), verbose, dest);
ExplainOneQuery(lfirst(l), verbose, analyze, dest);
}
/*
@ -82,11 +84,11 @@ ExplainQuery(Query *query, bool verbose, CommandDest dest)
*
*/
static void
ExplainOneQuery(Query *query, bool verbose, CommandDest dest)
ExplainOneQuery(Query *query, bool verbose, bool analyze, CommandDest dest)
{
char *s;
Plan *plan;
ExplainState *es;
double totaltime = 0;
/* planner will not cope with utility statements */
if (query->commandType == CMD_UTILITY)
@ -105,6 +107,34 @@ ExplainOneQuery(Query *query, bool verbose, CommandDest dest)
if (plan == NULL)
return;
/* Execute the plan for statistics if asked for */
if (analyze)
{
struct timeval starttime;
struct timeval endtime;
/*
* Set up the instrumentation for the top node.
* This will cascade during plan initialisation
*/
plan->instrument = InstrAlloc();
gettimeofday(&starttime, NULL);
ProcessQuery(query, plan, None);
CommandCounterIncrement();
gettimeofday(&endtime, NULL);
endtime.tv_sec -= starttime.tv_sec;
endtime.tv_usec -= starttime.tv_usec;
while (endtime.tv_usec < 0)
{
endtime.tv_usec += 1000000;
endtime.tv_sec--;
}
totaltime = (double) endtime.tv_sec +
(double) endtime.tv_usec / 1000000.0;
}
es = (ExplainState *) palloc(sizeof(ExplainState));
MemSet(es, 0, sizeof(ExplainState));
@ -117,6 +147,8 @@ ExplainOneQuery(Query *query, bool verbose, CommandDest dest)
if (es->printNodes)
{
char *s;
s = nodeToString(plan);
if (s)
{
@ -127,12 +159,15 @@ ExplainOneQuery(Query *query, bool verbose, CommandDest dest)
if (es->printCost)
{
s = Explain_PlanToString(plan, es);
if (s)
{
elog(NOTICE, "QUERY PLAN:\n\n%s", s);
pfree(s);
}
StringInfo str;
str = Explain_PlanToString(plan, es);
if (analyze)
appendStringInfo(str, "Total runtime: %.2f msec\n",
1000.0 * totaltime);
elog(NOTICE, "QUERY PLAN:\n\n%s", str->data);
pfree(str->data);
pfree(str);
}
if (es->printNodes)
@ -292,6 +327,17 @@ explain_outNode(StringInfo str, Plan *plan, int indent, ExplainState *es)
appendStringInfo(str, " (cost=%.2f..%.2f rows=%.0f width=%d)",
plan->startup_cost, plan->total_cost,
plan->plan_rows, plan->plan_width);
if ( plan->instrument && plan->instrument->nloops > 0 )
{
double nloops = plan->instrument->nloops;
appendStringInfo(str, " (actual time=%.2f..%.2f rows=%.0f loops=%.0f)",
1000.0 * plan->instrument->startup / nloops,
1000.0 * plan->instrument->total / nloops,
plan->instrument->ntuples / nloops,
plan->instrument->nloops);
}
}
appendStringInfo(str, "\n");
@ -393,14 +439,12 @@ explain_outNode(StringInfo str, Plan *plan, int indent, ExplainState *es)
}
}
static char *
static StringInfo
Explain_PlanToString(Plan *plan, ExplainState *es)
{
StringInfoData str;
StringInfo str = makeStringInfo();
/* see stringinfo.h for an explanation of this maneuver */
initStringInfo(&str);
if (plan != NULL)
explain_outNode(&str, plan, 0, es);
return str.data;
explain_outNode(str, plan, 0, es);
return str;
}