# PXC 8.4.6: LOCK\_ticket\_store\_ops mutex instances grow with cumulative connections **URL:** \ **Category:** MySQL & MariaDB\ **Tags:** pmm, mysql, percona\ **Created:** [August 24, 2026, 9:46pm UTC](https://forums.percona.com/t/pxc-8-4-6-lock-ticket-store-ops-mutex-instances-grow-with-cumulative-connections/41203 "2026-08-24T21:46:10Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![anil.joshi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/anil.joshi/32/13100_2.png) [@anil.joshi](https://forums.percona.com/u/anil.joshi)\ **Post date:** [August 25, 2026, 7:08am UTC](https://forums.percona.com/t/pxc-8-4-6-lock-ticket-store-ops-mutex-instances-grow-with-cumulative-connections/41203/2 "2026-08-25T07:08:34Z")
@Wu_Nan_Lin Yes, the similar issue was reproducible on this thread - [The number of wait/synch/mutex/sql/MDL\_ticket\_store::LOCK\_ticket\_store\_ops in mutex\_instances is constantly growing - #4 by anil.joshi](https://forums.percona.com/t/the-number-of-wait-synch-mutex-sql-mdl-ticket-store-lock-ticket-store-ops-in-mutex-instances-is-constantly-growing/39571/4) however that was simply observed with the **usual health check and operator monitoring process** where the session connects and monitor the cluster node without running any additional workload etc. E.g, ```auto mysql> show processlist; +------+----------------------+--------------------------------------------------------------------------+------+---------+------+--------------------------+------------------+---------+-----------+---------------+ | Id | User | Host | db | Command | Time | State | Info | Time_ms | Rows_sent | Rows_examined | +------+----------------------+--------------------------------------------------------------------------+------+---------+------+--------------------------+------------------+---------+-----------+---------------+ | 1 | system user | | NULL | Sleep | 1094 | wsrep: aborter idle | NULL | 1093398 | 0 | 0 | | 2 | system user | | NULL | Sleep | 1094 | innobase_commit_low (-1) | NULL | 1093398 | 0 | 0 | | 8 | event_scheduler | localhost | NULL | Daemon | 1094 | Waiting on empty queue | NULL | 1093148 | 0 | 0 | | 11 | system user | | NULL | Sleep | 1094 | wsrep: applier idle | NULL | 1093142 | 0 | 0 | | 480 | root | cluster1-haproxy-0.cluster1-haproxy.pxc-operator.svc.cluster.local:52740 | NULL | Query | 0 | init | show processlist | 0 | 0 | 0 | **| 2223 | unauthenticated user | cluster1-haproxy-0.cluster1-haproxy.pxc-operator.svc.cluster.local:46356 | NULL | Connect | 0 | login | NULL | 42 | 0 | 0 |** +------+----------------------+--------------------------------------------------------------------------+------+---------+------+--------------------------+------------------+---------+-----------+---------------+ 6 rows in set, 1 warning (0.00 sec) ``` ```auto |2025-11-14T12:52:34.467195Z| 4170 Connect|monitor@cluster1-haproxy-0.cluster1-haproxy.pxc-operator.svc.cluster.local on using SSL/TLS| |2025-11-14T12:52:34.612264Z| 4171 Connect|monitor@cluster1-haproxy-0.cluster1-haproxy.pxc-operator.svc.cluster.local on mysql using SSL/TLS| |2025-11-14T12:52:35.004880Z| 4174 Connect|monitor@cluster1-pxc-0.cluster1-pxc.pxc-operator.svc.cluster.local on using SSL/TLS| |2025-11-14T12:52:35.012697Z| 4175 Connect|monitor@cluster1-pxc-0.cluster1-pxc.pxc-operator.svc.cluster.local on using SSL/TLS| ``` Is your environment is also based on **PXC /K8s operator**? Is that spike you noticed just increasing from the PMM monitoring along without running any other operations on the cluster. What I mean is the cluster idle around that period ? Increasing **performance\_schema\_max\_mutex\_instances** doesn’t seems to be a solution rather a workaround for temporary mitigation. I’ll check this with the Dev or Internal team to get more clarity and then accordingly update you. --- _[View the full topic](https://forums.percona.com/t/pxc-8-4-6-lock-ticket-store-ops-mutex-instances-grow-with-cumulative-connections/41203)._