# Bug in pg\_stat\_monitor version 2.1 . Database Hungs **URL:** \ **Category:** Percona Distribution for PostgreSQL\ **Tags:** percona\ **Created:** [February 25, 2025, 3:50am UTC](https://forums.percona.com/t/bug-in-pg-stat-monitor-version-2-1-database-hungs/36906 "2025-02-25T03:50:38Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![harish.jaipu](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/harish.jaipu/32/20282_2.png) [@harish.jaipu](https://forums.percona.com/u/harish.jaipu)\ **Post date:** [February 25, 2025, 3:50am UTC](https://forums.percona.com/t/bug-in-pg-stat-monitor-version-2-1-database-hungs/36906/1 "2025-02-25T03:50:38Z")
Version psql (PostgreSQL) 16.6 - Percona Distribution. Database goes hung when the pg\_stat\_monitor query runs to fetch metrics. During this time no logs were gernerated in the error log and database was unresponsive and does not login. Killing this pid from ps -ef brought back the DB to normal state. This has happened three days in a row and we found out the issue now . Any one else faced the same issue ? Is this a bug in 2.1 version or is it in Percona ? Below is the query that caused the problem ```auto `SELECT /* agent='pgstatmonitor' */ ""pg_stat_monitor"".""bucket"", ""pg_stat_monitor"".""client_ip"", ""pg_stat_monitor"".""query"", ""pg_stat_monitor"".""calls"", ""pg_stat_monitor"".""shared_blks_hit"", ""pg_stat_monitor"".""shared_blks_read"", ""pg_stat_monitor"".""shared_blks_dirtied"", ""pg_stat_monitor"".""shared_blks_written"", ""pg_stat_monitor"".""local_blks_hit"", ""pg_stat_monitor"".""local_blks_read"", ""pg_stat_monitor"".""local_blks_dirtied"", ""pg_stat_monitor"".""local_blks_written"", ""pg_stat_monitor"".""temp_blks_read"", ""pg_stat_monitor"".""temp_blks_written"", ""pg_stat_monitor"".""blk_read_time"", ""pg_stat_monitor"".""blk_write_time"", ""pg_stat_monitor"".""resp_calls"", ""pg_stat_monitor"".""cpu_user_time"", ""pg_stat_monitor"".""cpu_sys_time"", ""pg_stat_monitor"".""rows"", ""pg_stat_monitor"".""relations"", ""pg_stat_monitor"".""datname"", ""pg_stat_monitor"".""userid"", ""pg_stat_monitor"".""top_queryid"", ""pg_stat_monitor"".""planid"", ""pg_stat_monitor"".""query_plan"", ""pg_stat_monitor"".""top_query"", ""pg_stat_monitor"".""application_name"", ""pg_stat_monitor"".""cmd_type"", ""pg_stat_monitor"".""cmd_type_text"", ""pg_stat_monitor"".""elevel"", ""pg_stat_monitor"".""sqlcode"", ""pg_stat_monitor"".""message"", ""pg_stat_monitor"".""pgsm_query_id"", ""pg_stat_monitor"".""dbid"", ""pg_stat_monitor"".""total_exec_time"", ""pg_stat_monitor"".""min_exec_time"", ""pg_stat_monitor"".""max_exec_time"", ""pg_stat_monitor"".""mean_exec_time"", ""pg_stat_monitor"".""stddev_exec_time"", ""pg_stat_monitor"".""total_plan_time"", ""pg_stat_monitor"".""min_plan_time"", ""pg_stat_monitor"".""max_plan_time"", ""pg_stat_monitor"".""mean_plan_time"", ""pg_stat_monitor"".""wal_records"", ""pg_stat_monitor"".""wal_fpi"", ""pg_stat_monitor"".""wal_bytes"", ""pg_stat_monitor"".""plans"", ""pg_stat_monitor"".""comments"", ""pg_stat_monitor"".""bucket_start_time"", ""pg_stat_monitor"".""username"" FROM ""pg_stat_monitor"" WHERE queryid IS NOT NULL AND query IS NOT NULL AND bucket_done AND pgsm_query_id IS NOT NULL" ` ``` Logs below which stopped writing after 01:11 am and went hung and continued writing after killing it _pg\_stat\_user\_tables_ _2025-02-25 01:03:41 IST [1021497]: [1-1] user=applicationid,db=techsupport\_analytics\_reports,host=100.0.2.15LOG: process 1021497 still waiting for ShareLock on transaction 216925398 after 1000.044 ms_ _2025-02-25 01:03:41 IST [1021497]: [2-1] user=applicationid,db=techsupport\_analytics\_reports,host=100.0.2.15DETAIL: Process holding the lock: 655052. Wait queue: 1021497._ _2025-02-25 01:03:41 IST [1021497]: [3-1] user=applicationid,db=techsupport\_analytics\_reports,host=100.0.2.15CONTEXT: while locking tuple (0,2) in relation “qrtz\_locks”_ _2025-02-25 01:03:41 IST [1021497]: [4-1] user=applicationid,db=techsupport\_analytics\_reports,host=100.0.2.15STATEMENT: SELECT \* FROM QRTZ\_LOCKS WHERE SCHED\_NAME = ‘MetabaseScheduler’ AND LOCK\_NAME = $1 FOR UPDATE_ _2025-02-25 01:04:01 IST [71003]: [1-1] user=applicationid,db=techsupport\_analytics\_reports,host=100.0.2.15LOG: process 71003 still waiting for ShareLock on transaction 216925398 after 1000.044 ms_ _2025-02-25 01:04:01 IST [71003]: [2-1] user=applicationid,db=techsupport\_analytics\_reports,host=100.0.2.15DETAIL: Process holding the lock: 655052. Wait queue: 1021497, 71003._ _2025-02-25 01:04:01 IST [71003]: [3-1] user=applicationid,db=techsupport\_analytics\_reports,host=100.0.2.15CONTEXT: while locking tuple (0,1) in relation “qrtz\_locks”_ _2025-02-25 01:04:01 IST [71003]: [4-1] user=applicationid,db=techsupport\_analytics\_reports,host=100.0.2.15STATEMENT: SELECT \* FROM QRTZ\_LOCKS WHERE SCHED\_NAME = ‘MetabaseScheduler’ AND LOCK\_NAME = $1 FOR UPDATE_ _**2025-02-25 01:11:17 IST [68307]: [43-1] user=,db=,host=LOG: checkpoint starting: time**_ _**2025-02-25 01:32:09 IST [68293]: [14-1] user=,db=,host=LOG: server process (PID 69787) was terminated by signal 9: Killed**_ _2025-02-25 01:32:09 IST [68293]: [15-1] user=,db=,host=DETAIL: Failed process was running: SELECT /_ agent=‘pgstatmonitor’ _/ “pg\_stat\_monitor”.“bucket”, “pg\_stat\_monitor”.“client\_ip”, “pg\_stat\_monitor”.“query”, “pg\_stat\_monitor”.“calls”, “pg\_stat\_monitor”.“shared\_blks\_hit”, “pg\_stat\_monitor”.“shared\_blks\_read”, “pg\_stat\_monitor”.“shared\_blks\_dirtied”, “pg\_stat\_monitor”.“shared\_blks\_written”, “pg\_stat\_monitor”.“local\_blks\_hit”, “pg\_stat\_monitor”.“local\_blks\_read”, “pg\_stat\_monitor”.“local\_blks\_dirtied”, “pg\_stat\_monitor”.“local\_blks\_written”, “pg\_stat\_monitor”.“temp\_blks\_read”, “pg\_stat\_monitor”.“temp\_blks\_written”, “pg\_stat\_monitor”.“blk\_read\_time”, “pg\_stat\_monitor”.“blk\_write\_time”, “pg\_stat\_monitor”.“resp\_calls”, “pg\_stat\_monitor”.“cpu\_user\_time”, “pg\_stat\_monitor”.“cpu\_sys\_time”, “pg\_stat\_monitor”.“rows”, “pg\_stat\_monitor”.“relations”, “pg\_stat\_monitor”.“datname”, “pg\_stat\_monitor”.“userid”, “pg\_stat\_monitor”.“top\_queryid”, “pg\_stat\_monitor”.“planid”, “pg\_stat\_monitor”.“query\_plan”, “pg\_stat\_monitor”.“top\_query”, “pg\_stat\_monitor”.“application\_name”, “pg\_stat\_monitor”.“cmd\_type”, "pg\_stat\_mon_ _2025-02-25 01:32:09 IST [68293]: [16-1] user=,db=,host=LOG: terminating any other active server processes_ _2025-02-25 01:32:10 IST [1084388]: [1-1] user=postgres,db=postgres,host=[local]FATAL: the database system is in recovery mode_ _2025-02-25 01:32:10 IST [1084387]: [1-1] user=applicationid,db=reporting\_master,host=100.0.8.106FATAL: the database system is in recovery mode_ _2025-02-25 01:32:10 IST [1084389]: [1-1] user=applicationid,db=reporting\_master,host=100.0.10.139FATAL: the database system is in recovery mode_ _2025-02-25 01:32:10 IST [1084391]: [1-1] user=pmmusr,db=postgres,host=172.150.0.56FATAL: the database system is in recovery mode_ _2025-02-25 01:32:10 IST [1084392]: [1-1] user=applicationid,db=keyman ,host=100.0.7.172FATAL: the database system is in recovery mode_ _2025-02-25 01:32:10 IST [1084395]: [1-1] user=applicationid,db=cim,host=100.0.9.30FATAL: the database system is in recovery mode_ _2025-02-25 01:32:10 IST [1084396]: [1-1] user=applicationid,db=cim,host=100.0.9.178FATAL: the database system is in recovery mode_ _2025-02-25 01:32:10 IST [1084397]: [1-1] user=applicationid,db=keyman ,host=100.0.9.178FATAL: the database system is in recovery mode_ _2025-02-25 01:32:10 IST [1084398]: [1-1] user=applicationid,db=keyman ,host=100.0.9.152FATAL: the database system is in recovery mode_ _2025-02-25 01:32:10 IST [1084399]: [1-1] user=applicationid,db=keyman ,host=100.0.8.106FATAL: the database system is in recovery mode_ ---
**Author:** ![harish.jaipu](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/harish.jaipu/32/20282_2.png) [@harish.jaipu](https://forums.percona.com/u/harish.jaipu)\ **Post date:** [March 3, 2025, 9:29am UTC](https://forums.percona.com/t/bug-in-pg-stat-monitor-version-2-1-database-hungs/36906/2 "2025-03-03T09:29:07Z")
Dear All, Can any one clarify if you have faced the same kind of issue ? ---
**Author:** ![Srikanth\_Lolugu](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/srikanth_lolugu/32/21494_2.png) [@Srikanth\_Lolugu](https://forums.percona.com/u/Srikanth_Lolugu)\ **Post date:** [July 15, 2025, 8:03pm UTC](https://forums.percona.com/t/bug-in-pg-stat-monitor-version-2-1-database-hungs/36906/3 "2025-07-15T20:03:10Z")
Hi Harish, We’re facing the same issue database hungs on pg\_stat\_monitor wait type, killing some random session from OS brings the DB back online. How are you sure that specific query only causing the DB to hung. ---
**Author:** ![harish.jaipu](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/harish.jaipu/32/20282_2.png) [@harish.jaipu](https://forums.percona.com/u/harish.jaipu)\ **Post date:** [July 16, 2025, 3:08am UTC](https://forums.percona.com/t/bug-in-pg-stat-monitor-version-2-1-database-hungs/36906/4 "2025-07-16T03:08:04Z")
Hi Srikanth, The Query i have shared is the problem. It’s from the pgstatmonitor itself. When it tries to get metadata from the DB it gets hung. Better to replace the extension with pgstatstatements. ---
**Author:** ![Srikanth\_Lolugu](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/srikanth_lolugu/32/21494_2.png) [@Srikanth\_Lolugu](https://forums.percona.com/u/Srikanth_Lolugu)\ **Post date:** [July 16, 2025, 1:27pm UTC](https://forums.percona.com/t/bug-in-pg-stat-monitor-version-2-1-database-hungs/36906/5 "2025-07-16T13:27:07Z")
Hi Harish, Thank you for sharing the query info!! I’m able to reproduce the issue partially. I’ve run above pmm SELECT manually, monitored for active sessions wait\_event. Observed that active sessions waiting on pg\_stat\_monitor wait\_event. ---
**Author:** ![harish.jaipu](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/harish.jaipu/32/20282_2.png) [@harish.jaipu](https://forums.percona.com/u/harish.jaipu)\ **Post date:** [July 16, 2025, 3:28pm UTC](https://forums.percona.com/t/bug-in-pg-stat-monitor-version-2-1-database-hungs/36906/6 "2025-07-16T15:28:15Z")
Cool!! Let me know if you find any resolution. ---
**Author:** ![Srikanth\_Lolugu](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/srikanth_lolugu/32/21494_2.png) [@Srikanth\_Lolugu](https://forums.percona.com/u/Srikanth_Lolugu)\ **Post date:** [November 8, 2025, 12:19am UTC](https://forums.percona.com/t/bug-in-pg-stat-monitor-version-2-1-database-hungs/36906/7 "2025-11-08T00:19:15Z")
Hi Harish, We’re not facing this issue for the past month after upgrading pg\_stat\_monitor to latest 2.2 version. However whenever we’re querying from pg\_stat\_monitor, we’re seeing a spike in the active connections but database is not getting hung.