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PG-1621: fix cmd_type mostly showing 0 values (#538) 

This was actually caused by two bugs internally:

* cmd_type was only set in some codepaths, other parts of the code
never set a value. Depending on which query / how was executed,
it was possibly never changed (after a reset to 0)
* the update first set the cmd_type, then reset all counters. As
the cmd_type is stored within the counters for some reason, this
reset its value to 0 in most execution paths, even if it was corretly
set before.

And according to this the fix is simple:

* cmd_type is now set in all codepaths except for failing queries,
as we only have the error string in this case, without the type.
* in the update logic, we again overwrite cmd_type with the proper
value after a reset
pull/543/head
Zsolt Parragi 2025-06-17 15:52:28 +02:00 committed by GitHub
parent f7dc7fb5fe
commit 61662cc58f
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GPG Key ID: B5690EEEBB952194
8 changed files with 51 additions and 15 deletions
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2
Makefile
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@ -4,7 +4,7 @@ MODULE_big = pg_stat_monitor
OBJS = hash_query.o guc.o pg_stat_monitor.o $(WIN32RES)
EXTENSION = pg_stat_monitor
DATA = pg_stat_monitor--2.0.sql pg_stat_monitor--1.0--2.0.sql pg_stat_monitor--2.0--2.1.sql
DATA = pg_stat_monitor--2.0.sql pg_stat_monitor--1.0--2.0.sql pg_stat_monitor--2.0--2.1.sql pg_stat_monitor--2.1--2.2.sql
PGFILEDESC = "pg_stat_monitor - execution statistics of SQL statements"

1
meson.build
View File

@ -17,6 +17,7 @@ install_data(
'pg_stat_monitor--2.0.sql',
'pg_stat_monitor--1.0--2.0.sql',
'pg_stat_monitor--2.0--2.1.sql',
'pg_stat_monitor--2.1--2.2.sql',
kwargs: contrib_data_args,
)

21
pg_stat_monitor--2.1--2.2.sql Normal file
View File

@ -0,0 +1,21 @@
/* contrib/pg_stat_monitor/pg_stat_monitor--2.1--2.2.sql */
-- complain if script is sourced in psql, rather than via CREATE EXTENSION
\echo Use "ALTER EXTENSION pg_stat_monitor" to load this file. \quit
CREATE OR REPLACE FUNCTION get_cmd_type (cmd_type INTEGER) RETURNS TEXT AS
$$
SELECT
CASE
WHEN cmd_type = 1 THEN 'SELECT'
WHEN cmd_type = 2 THEN 'UPDATE'
WHEN cmd_type = 3 THEN 'INSERT'
WHEN cmd_type = 4 THEN 'DELETE'
WHEN cmd_type = 5 AND current_setting('server_version_num')::int >= 150000 THEN 'MERGE'
WHEN cmd_type = 5 AND current_setting('server_version_num')::int < 150000 THEN 'UTILITY'
WHEN cmd_type = 6 AND current_setting('server_version_num')::int >= 150000 THEN 'UTILITY'
WHEN cmd_type = 6 AND current_setting('server_version_num')::int < 150000 THEN 'NOTHING'
WHEN cmd_type = 7 THEN 'NOTHING'
END
$$
LANGUAGE SQL PARALLEL SAFE;

20
pg_stat_monitor.c
View File

@ -37,7 +37,7 @@ typedef enum pgsmVersion
PG_MODULE_MAGIC;
#define BUILD_VERSION "2.1.1"
#define BUILD_VERSION "2.2.0"
/* Number of output arguments (columns) for various API versions */
#define PG_STAT_MONITOR_COLS_V1_0 52
@ -203,7 +203,7 @@ char *unpack_sql_state(int sql_state);
static pgsmEntry *pgsm_create_hash_entry(uint64 bucket_id, uint64 queryid, PlanInfo *plan_info);
static void pgsm_add_to_list(pgsmEntry *entry, char *query_text, int query_len);
static pgsmEntry *pgsm_get_entry_for_query(uint64 queryid, PlanInfo *plan_info, const char *query_text, int query_len, bool create);
static pgsmEntry *pgsm_get_entry_for_query(uint64 queryid, PlanInfo *plan_info, const char *query_text, int query_len, bool create, CmdType cmd_type);
static uint64 get_pgsm_query_id_hash(const char *norm_query, int len);
static void pgsm_cleanup_callback(void *arg);
@ -736,7 +736,7 @@ pgsm_ExecutorEnd(QueryDesc *queryDesc)
if (queryId != UINT64CONST(0) && queryDesc->totaltime && pgsm_enabled(nesting_level))
{
entry = pgsm_get_entry_for_query(queryId, plan_ptr, (char *) queryDesc->sourceText, strlen(queryDesc->sourceText), true);
entry = pgsm_get_entry_for_query(queryId, plan_ptr, (char *) queryDesc->sourceText, strlen(queryDesc->sourceText), true, queryDesc->operation);
if (!entry)
{
elog(DEBUG2, "[pg_stat_monitor] pgsm_ExecutorEnd: Failed to find entry for [%lu] %s.", queryId, queryDesc->sourceText);
@ -763,6 +763,8 @@ pgsm_ExecutorEnd(QueryDesc *queryDesc)
sys_info.stime = time_diff(rusage_end.ru_stime, rusage_start.ru_stime);
}
entry->counters.info.cmd_type = queryDesc->operation;
pgsm_update_entry(entry, /* entry */
NULL, /* query */
NULL, /* comments */
@ -908,7 +910,7 @@ pgsm_planner_hook(Query *parse, const char *query_string, int cursorOptions, Par
INSTR_TIME_SET_CURRENT(start);
if (MemoryContextIsValid(MessageContext))
entry = pgsm_get_entry_for_query(parse->queryId, NULL, query_string, strlen(query_string), true);
entry = pgsm_get_entry_for_query(parse->queryId, NULL, query_string, strlen(query_string), true, parse->commandType);
#if PG_VERSION_NUM >= 170000
nesting_level++;
@ -1199,7 +1201,7 @@ pgsm_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
query_text = (char *) CleanQuerytext(queryString, &location, &query_len);
entry->pgsm_query_id = get_pgsm_query_id_hash(query_text, query_len);
entry->counters.info.cmd_type = 0;
entry->counters.info.cmd_type = pstmt->commandType;
pgsm_add_to_list(entry, query_text, query_len);
@ -1741,7 +1743,7 @@ pgsm_add_to_list(pgsmEntry *entry, char *query_text, int query_len)
}
static pgsmEntry *
pgsm_get_entry_for_query(uint64 queryid, PlanInfo *plan_info, const char *query_text, int query_len, bool create)
pgsm_get_entry_for_query(uint64 queryid, PlanInfo *plan_info, const char *query_text, int query_len, bool create, CmdType cmd_type)
{
pgsmEntry *entry = NULL;
ListCell *lc = NULL;
@ -1778,6 +1780,7 @@ pgsm_get_entry_for_query(uint64 queryid, PlanInfo *plan_info, const char *query_
* worry about these.
*/
entry->pgsm_query_id = get_pgsm_query_id_hash(query_text, query_len);
entry->counters.info.cmd_type = cmd_type;
pgsm_add_to_list(entry, (char *) query_text, query_len);
}
@ -2087,6 +2090,11 @@ pgsm_store(pgsmEntry *entry)
reset, /* reset */
PGSM_STORE);
if (reset)
{
shared_hash_entry->counters.info.cmd_type = entry->counters.info.cmd_type;
}
memset(&entry->counters, 0, sizeof(entry->counters));
pgsm_lock_release(pgsm);
}

2
pg_stat_monitor.control
View File

@ -1,5 +1,5 @@
# pg_stat_monitor extension
comment = 'The pg_stat_monitor is a PostgreSQL Query Performance Monitoring tool, based on PostgreSQL contrib module pg_stat_statements. pg_stat_monitor provides aggregated statistics, client information, plan details including plan, and histogram information.'
default_version = '2.1'
default_version = '2.2'
module_pathname = '$libdir/pg_stat_monitor'
relocatable = true

10
regression/expected/cmd_type.out
View File

@ -27,16 +27,16 @@ DROP TABLE t2;
SELECT query, cmd_type, cmd_type_text FROM pg_stat_monitor ORDER BY query COLLATE "C";
query | cmd_type | cmd_type_text
--------------------------------+----------+---------------
CREATE TABLE t1 (a INTEGER) | 0 |
CREATE TABLE t2 (b INTEGER) | 0 |
CREATE TABLE t1 (a INTEGER) | 5 | UTILITY
CREATE TABLE t2 (b INTEGER) | 5 | UTILITY
DELETE FROM t1 | 4 | DELETE
DROP TABLE t1 | 0 |
DROP TABLE t2 | 0 |
DROP TABLE t1 | 5 | UTILITY
DROP TABLE t2 | 5 | UTILITY
INSERT INTO t1 VALUES(1) | 3 | INSERT
SELECT a FROM t1 | 1 | SELECT
SELECT b FROM t2 FOR UPDATE | 1 | SELECT
SELECT pg_stat_monitor_reset() | 1 | SELECT
TRUNCATE t1 | 0 |
TRUNCATE t1 | 5 | UTILITY
UPDATE t1 SET a = 2 | 2 | UPDATE
(11 rows)

8
regression/expected/cmd_type_1.out
View File

@ -23,16 +23,22 @@ SELECT b FROM t2 FOR UPDATE;
TRUNCATE t1;
DROP TABLE t1;
DROP TABLE t2;
SELECT query, cmd_type, cmd_type_text FROM pg_stat_monitor ORDER BY query COLLATE "C";
query | cmd_type | cmd_type_text
--------------------------------+----------+---------------
CREATE TABLE t1 (a INTEGER) | 6 | UTILITY
CREATE TABLE t2 (b INTEGER) | 6 | UTILITY
DELETE FROM t1 | 4 | DELETE
DROP TABLE t1 | 6 | UTILITY
DROP TABLE t2 | 6 | UTILITY
INSERT INTO t1 VALUES(1) | 3 | INSERT
SELECT a FROM t1 | 1 | SELECT
SELECT b FROM t2 FOR UPDATE | 1 | SELECT
SELECT pg_stat_monitor_reset() | 1 | SELECT
TRUNCATE t1 | 6 | UTILITY
UPDATE t1 SET a = 2 | 2 | UPDATE
(6 rows)
(11 rows)
SELECT pg_stat_monitor_reset();
pg_stat_monitor_reset

2
regression/expected/version.out
View File

@ -2,7 +2,7 @@ CREATE EXTENSION pg_stat_monitor;
SELECT pg_stat_monitor_version();
pg_stat_monitor_version
-------------------------
2.1.1
2.2.0
(1 row)
DROP EXTENSION pg_stat_monitor;