# Best practices for max\_connections and threadsConnected monitoring in PXC 8.0

**URL:** <https://forums.percona.com/t/best-practices-for-max-connections-and-threadsconnected-monitoring-in-pxc-8-0/40052>\
**Category:** Uncategorized\
**Created:** [January 15, 2026, 9:37am UTC](https://forums.percona.com/t/best-practices-for-max-connections-and-threadsconnected-monitoring-in-pxc-8-0/40052 "2026-01-15T09:37:10Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![SQLCaesar](https://avatars.discourse-cdn.com/v4/letter/s/9fc348/32.png) [@SQLCaesar](https://forums.percona.com/u/SQLCaesar)\
**Post date:** [January 15, 2026, 9:37am UTC](https://forums.percona.com/t/best-practices-for-max-connections-and-threadsconnected-monitoring-in-pxc-8-0/40052/1 "2026-01-15T09:37:10Z")

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Hi all,

I would like to discuss the impact of high mysql connection counts (threadsConnected) on Percona XtraDB Cluster (PXC) 8.0 health and performance. Let’s assume 5 node cluster (PXC 8.0) including one garbd deamon with 2 load balancers (with single-writer setup)

In general, is my assumption correct that even if threadsConnected is relatively high (cca 110 connections), the cluster’s replication health remains unaffected as long as Flow Control is not triggered?

In other words, is connection count a secondary metric compared to wsrep\_flow\_control\_paused, or can a high number of open connections (even if many are in a Sleep state) negatively impact the cluster’s health and performance?

Your input will be much appreciated!

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**Author:** ![Wayne\_Leutwyler](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/wayne_leutwyler/32/20829_2.png) [@Wayne\_Leutwyler](https://forums.percona.com/u/Wayne_Leutwyler)\
**Post date:** [January 16, 2026, 11:13pm UTC](https://forums.percona.com/t/best-practices-for-max-connections-and-threadsconnected-monitoring-in-pxc-8-0/40052/2 "2026-01-16T23:13:15Z")

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> [@SQLCaesar](#):
>
> In general, is my assumption correct that even if threadsConnected is relatively high (cca 110 connections), the cluster’s replication health remains unaffected as long as Flow Control is not triggered?

Yes, your assumption is basically correct.

Flow Control is the signal to watch, not raw connection count.

PXC Primary health signals.

These directly describe cluster health:

- wsrep\_flow\_control\_paused
- wsrep\_flow\_control\_active
- wsrep\_local\_recv\_queue
- wsrep\_local\_send\_queue
- wsrep\_cert\_deps\_distance
- wsrep\_local\_cert\_failures

If these are calm, the cluster is replicating cleanly.