database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-30 21:42:05 +03:00
Code Activity

Add SETTINGS option to EXPLAIN, to print modified settings.

Browse Source 
Query planning is affected by a number of configuration options, and it
may be crucial to know which of those options were set to non-default
values.  With this patch you can say EXPLAIN (SETTINGS ON) to include
that information in the query plan.  Only options affecting planning,
with values different from the built-in default are printed.

This patch also adds auto_explain.log_settings option, providing the
same capability in auto_explain module.

Author: Tomas Vondra
Reviewed-by: Rafia Sabih, John Naylor
Discussion: https://postgr.es/m/e1791b4c-df9c-be02-edc5-7c8874944be0@2ndquadrant.com
This commit is contained in:
Tomas Vondra
2019-04-04 00:04:31 +02:00
parent d1f04b96b9
commit ea569d64ac
8 changed files with 333 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files

76
src/backend/commands/explain.c
View File

@ -29,6 +29,7 @@
#include "storage/bufmgr.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/guc_tables.h"
#include "utils/json.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
@ -162,6 +163,8 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt, const char *queryString,
es->costs = defGetBoolean(opt);
else if (strcmp(opt->defname, "buffers") == 0)
es->buffers = defGetBoolean(opt);
else if (strcmp(opt->defname, "settings") == 0)
es->settings = defGetBoolean(opt);
else if (strcmp(opt->defname, "timing") == 0)
{
timing_set = true;
@ -596,6 +599,73 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
ExplainCloseGroup("Query", NULL, true, es);
}
/*
* ExplainPrintSettings -
* Print summary of modified settings affecting query planning.
*/
static void
ExplainPrintSettings(ExplainState *es)
{
int num;
struct config_generic **gucs;
/* bail out if information about settings not requested */
if (!es->settings)
return;
/* request an array of relevant settings */
gucs = get_explain_guc_options(&num);
/* also bail out of there are no options */
if (!num)
return;
if (es->format != EXPLAIN_FORMAT_TEXT)
{
int i;
ExplainOpenGroup("Settings", "Settings", true, es);
for (i = 0; i < num; i++)
{
char *setting;
struct config_generic *conf = gucs[i];
setting = GetConfigOptionByName(conf->name, NULL, true);
ExplainPropertyText(conf->name, setting, es);
}
ExplainCloseGroup("Settings", "Settings", true, es);
}
else
{
int i;
StringInfoData str;
initStringInfo(&str);
for (i = 0; i < num; i++)
{
char *setting;
struct config_generic *conf = gucs[i];
if (i > 0)
appendStringInfoString(&str, ", ");
setting = GetConfigOptionByName(conf->name, NULL, true);
if (setting)
appendStringInfo(&str, "%s = '%s'", conf->name, setting);
else
appendStringInfo(&str, "%s = NULL", conf->name);
}
if (num > 0)
ExplainPropertyText("Settings", str.data, es);
}
}
/*
* ExplainPrintPlan -
* convert a QueryDesc's plan tree to text and append it to es->str
@ -633,6 +703,12 @@ ExplainPrintPlan(ExplainState *es, QueryDesc *queryDesc)
if (IsA(ps, GatherState) &&((Gather *) ps->plan)->invisible)
ps = outerPlanState(ps);
ExplainNode(ps, NIL, NULL, NULL, es);
/*
* If requested, include information about GUC parameters with values
* that don't match the built-in defaults.
*/
ExplainPrintSettings(es);
}
/*