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Allow compute_query_id to be set to 'auto' and make it default

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Allowing only on/off meant that all either all existing configuration
guides would become obsolete if we disabled it by default, or that we
would have to accept a performance loss in the default config if we
enabled it by default.  By allowing 'auto' as a middle ground, the
performance cost is only paid by those who enable pg_stat_statements and
similar modules.

I only edited the release notes to comment-out a paragraph that is now
factually wrong; further edits are probably needed to describe the
related change in more detail.

Author: Julien Rouhaud <rjuju123@gmail.com>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/20210513002623.eugftm4nk2lvvks3@nol
This commit is contained in:
Alvaro Herrera
2021-05-15 14:13:09 -04:00
parent 30d8bad494
commit cafde58b33
14 changed files with 108 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
src/backend/utils/misc/guc.c
View File

@@ -101,6 +101,7 @@
#include "utils/plancache.h"
#include "utils/portal.h"
#include "utils/ps_status.h"
#include "utils/queryjumble.h"
#include "utils/rls.h"
#include "utils/snapmgr.h"
#include "utils/tzparser.h"
@@ -402,6 +403,23 @@ static const struct config_enum_entry backslash_quote_options[] = {
{NULL, 0, false}
};
/*
* Although only "on", "off", and "auto" are documented, we accept
* all the likely variants of "on" and "off".
*/
static const struct config_enum_entry compute_query_id_options[] = {
{"auto", COMPUTE_QUERY_ID_AUTO, false},
{"on", COMPUTE_QUERY_ID_ON, false},
{"off", COMPUTE_QUERY_ID_OFF, false},
{"true", COMPUTE_QUERY_ID_ON, true},
{"false", COMPUTE_QUERY_ID_OFF, true},
{"yes", COMPUTE_QUERY_ID_ON, true},
{"no", COMPUTE_QUERY_ID_OFF, true},
{"1", COMPUTE_QUERY_ID_ON, true},
{"0", COMPUTE_QUERY_ID_OFF, true},
{NULL, 0, false}
};
/*
* Although only "on", "off", and "partition" are documented, we
* accept all the likely variants of "on" and "off".
@@ -534,7 +552,6 @@ extern const struct config_enum_entry dynamic_shared_memory_options[];
/*
* GUC option variables that are exported from this module
*/
bool compute_query_id = false;
bool log_duration = false;
bool Debug_print_plan = false;
bool Debug_print_parse = false;
@@ -1441,15 +1458,6 @@ static struct config_bool ConfigureNamesBool[] =
true,
NULL, NULL, NULL
},
{
{"compute_query_id", PGC_SUSET, STATS_MONITORING,
gettext_noop("Compute query identifiers."),
NULL
},
&compute_query_id,
false,
NULL, NULL, NULL
},
{
{"log_parser_stats", PGC_SUSET, STATS_MONITORING,
gettext_noop("Writes parser performance statistics to the server log."),
@@ -4619,6 +4627,16 @@ static struct config_enum ConfigureNamesEnum[] =
NULL, NULL, NULL
},
{
{"compute_query_id", PGC_SUSET, STATS_MONITORING,
gettext_noop("Compute query identifiers."),
NULL
},
&compute_query_id,
COMPUTE_QUERY_ID_AUTO, compute_query_id_options,
NULL, NULL, NULL
},
{
{"constraint_exclusion", PGC_USERSET, QUERY_TUNING_OTHER,
gettext_noop("Enables the planner to use constraints to optimize queries."),

2
src/backend/utils/misc/postgresql.conf.sample
View File

@@ -604,7 +604,7 @@
# - Monitoring -
#compute_query_id = off
#compute_query_id = auto
#log_statement_stats = off
#log_parser_stats = off
#log_planner_stats = off

21
src/backend/utils/misc/queryjumble.c
View File

@@ -39,6 +39,12 @@
#define JUMBLE_SIZE 1024 /* query serialization buffer size */
/* GUC parameters */
int compute_query_id = COMPUTE_QUERY_ID_AUTO;
/* True when compute_query_id is ON, or AUTO and a module requests them */
bool query_id_enabled = false;
static uint64 compute_utility_query_id(const char *str, int query_location, int query_len);
static void AppendJumble(JumbleState *jstate,
const unsigned char *item, Size size);
@@ -96,6 +102,8 @@ JumbleQuery(Query *query, const char *querytext)
{
JumbleState *jstate = NULL;
Assert(IsQueryIdEnabled());
if (query->utilityStmt)
{
query->queryId = compute_utility_query_id(querytext,
@@ -132,6 +140,19 @@ JumbleQuery(Query *query, const char *querytext)
return jstate;
}
/*
* Enables query identifier computation.
*
* Third-party plugins can use this function to inform core that they require
* a query identifier to be computed.
*/
void
EnableQueryId(void)
{
if (compute_query_id != COMPUTE_QUERY_ID_OFF)
query_id_enabled = true;
}
/*
* Compute a query identifier for the given utility query string.
*/