Here's a first attempt at what was suggested. If you say "auto" it
remains auto in SHOW, but it gets enabled if a module asks for it.
Not final yet, but I thought I'd throw it out for early commentary ...
--
Álvaro Herrera Valdivia, Chile
diff --git a/contrib/pg_stat_statements/expected/pg_stat_statements.out b/contrib/pg_stat_statements/expected/pg_stat_statements.out
index 40b5109b55..f7ce01539f 100644
--- a/contrib/pg_stat_statements/expected/pg_stat_statements.out
+++ b/contrib/pg_stat_statements/expected/pg_stat_statements.out
@@ -1067,4 +1067,20 @@ SELECT COUNT(*) FROM pg_stat_statements WHERE query LIKE '%SELECT GROUPING%';
2
(1 row)
+-- Check that pg_stat_statements() will complain if the configuration appears
+-- to be broken.
+SET compute_query_id = off;
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT count(*) FROM pg_stat_statements;
+WARNING: query identifier calculation is disabled
+ count
+-------
+ 0
+(1 row)
+
DROP EXTENSION pg_stat_statements;
diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c
index a85f962801..fab684a649 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.c
+++ b/contrib/pg_stat_statements/pg_stat_statements.c
@@ -369,6 +369,12 @@ _PG_init(void)
if (!process_shared_preload_libraries_in_progress)
return;
+ /*
+ * Inform the postmaster that we want to enable query_id calculation if
+ * compute_query_id is set to auto.
+ */
+ EnableQueryId();
+
/*
* Define (or redefine) custom GUC variables.
*/
@@ -1617,6 +1623,18 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
*/
LWLockAcquire(pgss->lock, LW_SHARED);
+ /*
+ * If no query_id has been computed for the calling query and there is
+ * no entries stored, then there's likely a configuration error that caller
+ * may not be aware of so point it out.
+ */
+ if (pgstat_get_my_query_id() == UINT64CONST(0) &&
+ compute_query_id == COMPUTE_QUERY_ID_OFF &&
+ hash_get_num_entries(pgss_hash) == 0)
+ ereport(WARNING,
+ errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("query identifier calculation is disabled"));
+
if (showtext)
{
/*
diff --git a/contrib/pg_stat_statements/pg_stat_statements.conf b/contrib/pg_stat_statements/pg_stat_statements.conf
index e47b26040f..13346e2807 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.conf
+++ b/contrib/pg_stat_statements/pg_stat_statements.conf
@@ -1,2 +1 @@
shared_preload_libraries = 'pg_stat_statements'
-compute_query_id = on
diff --git a/contrib/pg_stat_statements/sql/pg_stat_statements.sql b/contrib/pg_stat_statements/sql/pg_stat_statements.sql
index bc3b6493e6..827a8e3d18 100644
--- a/contrib/pg_stat_statements/sql/pg_stat_statements.sql
+++ b/contrib/pg_stat_statements/sql/pg_stat_statements.sql
@@ -437,4 +437,10 @@ SELECT (
SELECT COUNT(*) FROM pg_stat_statements WHERE query LIKE '%SELECT GROUPING%';
+-- Check that pg_stat_statements() will complain if the configuration appears
+-- to be broken.
+SET compute_query_id = off;
+SELECT pg_stat_statements_reset();
+SELECT count(*) FROM pg_stat_statements;
+
DROP EXTENSION pg_stat_statements;
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 45bd1f1b7e..60d8b24f5e 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -7627,7 +7627,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
<variablelist>
<varlistentry id="guc-compute-query-id" xreflabel="compute_query_id">
- <term><varname>compute_query_id</varname> (<type>boolean</type>)
+ <term><varname>compute_query_id</varname> (<type>enum</type>)
<indexterm>
<primary><varname>compute_query_id</varname> configuration parameter</primary>
</indexterm>
@@ -7643,7 +7643,12 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
identifier to be computed. Note that an external module can
alternatively be used if the in-core query identifier computation
method is not acceptable. In this case, in-core computation
- must be disabled. The default is <literal>off</literal>.
+ must be always disabled.
+ Valid values are <literal>off</literal> (always disabled),
+ <literal>on</literal> (always enabled) and <literal>auto</literal>,
+ which let modules such as <xref linkend="pgstatstatements"/>
+ automatically enable it.
+ The default is <literal>auto</literal>.
</para>
<note>
<para>
diff --git a/doc/src/sgml/pgstatstatements.sgml b/doc/src/sgml/pgstatstatements.sgml
index bc2b6038ee..acfb134797 100644
--- a/doc/src/sgml/pgstatstatements.sgml
+++ b/doc/src/sgml/pgstatstatements.sgml
@@ -22,10 +22,15 @@
<para>
The module will not track statistics unless query
- identifiers are calculated. This can be done by enabling <xref
- linkend="guc-compute-query-id"/> or using a third-party module that
- computes its own query identifiers. Note that all statistics tracked
- by this module must be reset if the query identifier method is changed.
+ identifiers are calculated. This is done by automatically when this
+ extension is configured in <literal>shared_preload_libraries</literal> and
+ <xref linkend="guc-compute-query-id"/> is set to <literal>auto</literal>
+ (which is the default value), or always if <xref
+ linkend="guc-compute-query-id"/> is set to <literal>on</literal>.
+ You must set <xref linkend="guc-compute-query-id"/> to <literal>off</literal>
+ if you want to use a third-party module that computes its own query
+ identifiers. Note that all statistics tracked by this module must be
+ reset if the query identifier method is changed.
</para>
<para>
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 1202bf85a3..9a60865d19 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -245,7 +245,7 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
es->summary = (summary_set) ? es->summary : es->analyze;
query = castNode(Query, stmt->query);
- if (compute_query_id)
+ if (IsQueryIdEnabled())
jstate = JumbleQuery(query, pstate->p_sourcetext);
if (post_parse_analyze_hook)
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 168198acd1..201b88d1ad 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -124,7 +124,7 @@ parse_analyze(RawStmt *parseTree, const char *sourceText,
query = transformTopLevelStmt(pstate, parseTree);
- if (compute_query_id)
+ if (IsQueryIdEnabled())
jstate = JumbleQuery(query, sourceText);
if (post_parse_analyze_hook)
@@ -163,7 +163,7 @@ parse_analyze_varparams(RawStmt *parseTree, const char *sourceText,
/* make sure all is well with parameter types */
check_variable_parameters(pstate, query);
- if (compute_query_id)
+ if (IsQueryIdEnabled())
jstate = JumbleQuery(query, sourceText);
if (post_parse_analyze_hook)
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 6833f0f7f2..9ca1095f47 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -521,6 +521,7 @@ typedef struct
pg_time_t first_syslogger_file_time;
bool redirection_done;
bool IsBinaryUpgrade;
+ bool auto_query_id_enabled;
int max_safe_fds;
int MaxBackends;
#ifdef WIN32
@@ -6168,6 +6169,7 @@ save_backend_variables(BackendParameters *param, Port *port,
param->redirection_done = redirection_done;
param->IsBinaryUpgrade = IsBinaryUpgrade;
+ param->auto_query_id_enabled = auto_query_id_enabled;
param->max_safe_fds = max_safe_fds;
param->MaxBackends = MaxBackends;
@@ -6401,6 +6403,7 @@ restore_backend_variables(BackendParameters *param, Port *port)
redirection_done = param->redirection_done;
IsBinaryUpgrade = param->IsBinaryUpgrade;
+ auto_query_id_enabled = param->auto_query_id_enabled;
max_safe_fds = param->max_safe_fds;
MaxBackends = param->MaxBackends;
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 6200699ddd..f9c6ca80f1 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -704,7 +704,7 @@ pg_analyze_and_rewrite_params(RawStmt *parsetree,
query = transformTopLevelStmt(pstate, parsetree);
- if (compute_query_id)
+ if (IsQueryIdEnabled())
jstate = JumbleQuery(query, query_string);
if (post_parse_analyze_hook)
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index eb7f7181e4..4d88982a75 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -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."),
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index efde01ee56..6e36e4c2ef 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -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
diff --git a/src/backend/utils/misc/queryjumble.c b/src/backend/utils/misc/queryjumble.c
index f004a9ce8c..c4683d9ed2 100644
--- a/src/backend/utils/misc/queryjumble.c
+++ b/src/backend/utils/misc/queryjumble.c
@@ -39,6 +39,12 @@
#define JUMBLE_SIZE 1024 /* query serialization buffer size */
+/* GUC parameters */
+int compute_query_id = COMPUTE_QUERY_ID_AUTO;
+
+/* True when a module requests query IDs and they're set auto */
+bool auto_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);
@@ -132,6 +138,33 @@ JumbleQuery(Query *query, const char *querytext)
return jstate;
}
+/*
+ * Enables query identifier computation if the GUC is set to auto.
+ *
+ * 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_AUTO)
+ auto_query_id_enabled = true;
+}
+
+/*
+ * Returns whether query identifier computation has been enabled, either
+ * directly in the GUC or by a module when the setting is 'auto'.
+ */
+bool
+IsQueryIdEnabled(void)
+{
+ if (compute_query_id == COMPUTE_QUERY_ID_OFF)
+ return false;
+ if (compute_query_id == COMPUTE_QUERY_ID_ON)
+ return true;
+ return auto_query_id_enabled;
+}
+
/*
* Compute a query identifier for the given utility query string.
*/
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 24a5d9d3fb..a7c3a4958e 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -247,7 +247,6 @@ extern bool log_btree_build_stats;
extern PGDLLIMPORT bool check_function_bodies;
extern bool session_auth_is_superuser;
-extern bool compute_query_id;
extern bool log_duration;
extern int log_parameter_max_length;
extern int log_parameter_max_length_on_error;
diff --git a/src/include/utils/queryjumble.h b/src/include/utils/queryjumble.h
index 83ba7339fa..60389f15b4 100644
--- a/src/include/utils/queryjumble.h
+++ b/src/include/utils/queryjumble.h
@@ -52,7 +52,23 @@ typedef struct JumbleState
int highest_extern_param_id;
} JumbleState;
-const char *CleanQuerytext(const char *query, int *location, int *len);
-JumbleState *JumbleQuery(Query *query, const char *querytext);
+/* Values for the compute_query_id GUC */
+typedef enum
+{
+ COMPUTE_QUERY_ID_OFF,
+ COMPUTE_QUERY_ID_ON,
+ COMPUTE_QUERY_ID_AUTO
+} ComputeQueryIdType;
+
+/* GUC parameters */
+extern int compute_query_id;
+
+/* Not a GUC: set true if any modules turn "auto" into "on" */
+extern bool auto_query_id_enabled;
+
+extern const char *CleanQuerytext(const char *query, int *location, int *len);
+extern JumbleState *JumbleQuery(Query *query, const char *querytext);
+extern void EnableQueryId(void);
+extern bool IsQueryIdEnabled(void);
#endif /* QUERYJUMBLE_H */
