# Facing Connection Closure Issues with Percona MySQL and ProxySQL Load Balancing **URL:** \ **Category:** Percona XtraDB Cluster 8.x\ **Tags:** mysql\ **Created:** [February 6, 2024, 12:23pm UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290 "2024-02-06T12:23:01Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Santhosh\_Pandi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/santhosh_pandi/32/11021_2.png) [@Santhosh\_Pandi](https://forums.percona.com/u/Santhosh_Pandi)\ **Post date:** [February 6, 2024, 12:23pm UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/1 "2024-02-06T12:23:01Z")
Hi everyone, I hope you’re doing well. I’ve been encountering some issues with Percona MySQL and ProxySQL for load balancing in my web applications. Here’s a brief overview of the problem: **Problem Description:** - After deploying my web applications, they initially work fine for around 10 or 15 minutes. - However, after this initial period, the connections to Percona MySQL through ProxySQL are being closed unexpectedly. **Error Message:** - The error message I’m receiving indicates that the connections are being closed prematurely. Here’s a sample error message: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@… (No operations allowed after connection closed.) **Configuration Details:** - I’m using Percona MySQL as the backend database and ProxySQL for load balancing. - The connection pool is managed by HikariCP. **Troubleshooting Steps Taken:** - I’ve checked the database server logs and configuration, but I couldn’t find any issues on that end. - I’ve also reviewed the configuration of ProxySQL and HikariCP, ensuring that they’re set up correctly. **Request for Assistance:** - I would appreciate any insights or suggestions on how to troubleshoot and resolve this issue. - If anyone has experienced similar issues or has expertise in Percona MySQL and ProxySQL configuration, your guidance would be invaluable. **Additional Information:** - If there are specific logs, configurations, or settings that you’d like me to provide for further analysis, please let me know, and I’ll gladly share them. Thank you in advance for your help and support. Best regards, sandhoshpandi ---
**Author:** ![Mughees\_Ahmed](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/mughees_ahmed/32/9028_2.png) [@Mughees\_Ahmed](https://forums.percona.com/u/Mughees_Ahmed)\ **Post date:** [February 6, 2024, 12:33pm UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/2 "2024-02-06T12:33:40Z")
@Santhosh_Pandi, what is wait\_timeout variable in MySQL and maxLifetime in Hikari config ? also, check the same mysql-wait\_timeout in proxysql. thanks ---
**Author:** ![Mughees\_Ahmed](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/mughees_ahmed/32/9028_2.png) [@Mughees\_Ahmed](https://forums.percona.com/u/Mughees_Ahmed)\ **Post date:** [February 6, 2024, 12:37pm UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/3 "2024-02-06T12:37:13Z")
> [@Santhosh\_Pandi](#): > > HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@… (No operations allowed after connection closed.) will recommend to have set wait\_timeout variable in MySQL to be greater than maxLifetime in Hikari, so as to avoid connections being killed by MySQL. e,g by giving maxLifeTime(20000) value less than wait\_timeout(28800) in mysql ---
**Author:** ![Santhosh\_Pandi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/santhosh_pandi/32/11021_2.png) [@Santhosh\_Pandi](https://forums.percona.com/u/Santhosh_Pandi)\ **Post date:** [February 6, 2024, 1:03pm UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/4 "2024-02-06T13:03:15Z")
thank you for your immediate response, i will check and revert back soon ---
**Author:** ![Santhosh\_Pandi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/santhosh_pandi/32/11021_2.png) [@Santhosh\_Pandi](https://forums.percona.com/u/Santhosh_Pandi)\ **Post date:** [February 6, 2024, 1:17pm UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/5 "2024-02-06T13:17:55Z")
2024-02-06 13:10:47 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:40452 2024-02-06 13:10:49 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:40478 2024-02-06 13:10:49 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:40494 2024-02-06 13:10:52 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:40542 this error was throws 20.113.158.117 this is applications is deployed ---
**Author:** ![Santhosh\_Pandi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/santhosh_pandi/32/11021_2.png) [@Santhosh\_Pandi](https://forums.percona.com/u/Santhosh_Pandi)\ **Post date:** [February 6, 2024, 2:01pm UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/6 "2024-02-06T14:01:42Z")
MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection this error also occur sir how to solve this issue ---
**Author:** ![Mughees\_Ahmed](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/mughees_ahmed/32/9028_2.png) [@Mughees\_Ahmed](https://forums.percona.com/u/Mughees_Ahmed)\ **Post date:** [February 7, 2024, 1:49am UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/7 "2024-02-07T01:49:02Z")
@Santhosh_Pandi If the client disconnects in a not graceful way, proxysql will generate a warning. This can be useful in identifying patterns, for example, if the issue is mostly from an application and not from another ProxySQL 2.0.8 introduced a new variable `mysql-log_unhealthy_connections` to suppress messages related to unhealthy client’s connections being closed. ---
**Author:** ![Santhosh\_Pandi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/santhosh_pandi/32/11021_2.png) [@Santhosh\_Pandi](https://forums.percona.com/u/Santhosh_Pandi)\ **Post date:** [February 7, 2024, 8:27am UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/8 "2024-02-07T08:27:27Z")
2024-02-07 08:25:38 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:43590 2024-02-07 08:25:40 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:43632 2024-02-07 08:25:42 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:57662 2024-02-07 08:25:42 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:57670 2024-02-07 08:25:42 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:57686 2024-02-07 08:25:43 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:57696 2024-02-07 08:25:43 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:57702 2024-02-07 08:25:44 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:57714 2024-02-07 08:25:48 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:57748 2024-02-07 08:25:48 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:57758 2024-02-07 08:25:49 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:57774 2024-02-07 08:25:52 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:57790 2024-02-07 08:26:00 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:56634 2024-02-07 08:26:02 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:35876 2024-02-07 08:26:02 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:35888 2024-02-07 08:26:04 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:35950 20.113.158.117 this is ip is i had deployed server ip why this error can occurs ,but some time working and some time not working ---
**Author:** ![Santhosh\_Pandi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/santhosh_pandi/32/11021_2.png) [@Santhosh\_Pandi](https://forums.percona.com/u/Santhosh_Pandi)\ **Post date:** [February 7, 2024, 8:30am UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/9 "2024-02-07T08:30:01Z")
2024-02-07 08:29:18 MySQL\_Session.cpp:5509:handler\_\_\_status\_CONNECTING\_CLIENT\_\_\_STATE\_SERVER\_HANDSHAKE(): [WARNING] mysql-max\_connections reached. Returning ‘Too many connections’ 2024-02-07 08:29:19 MySQL\_Session.cpp:5509:handler\_\_\_status\_CONNECTING\_CLIENT\_\_\_STATE\_SERVER\_HANDSHAKE(): [WARNING] mysql-max\_connections reached. Returning ‘Too many connections’ i have connect two users only but throw too many connections error ---
**Author:** ![Santhosh\_Pandi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/santhosh_pandi/32/11021_2.png) [@Santhosh\_Pandi](https://forums.percona.com/u/Santhosh_Pandi)\ **Post date:** [February 7, 2024, 11:15am UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/10 "2024-02-07T11:15:37Z")
hread.cpp:3631:process\_data\_on\_data\_stream(): [WARNING] Detected broken idle connection on 20.52.153.225:3306 2024-02-07 11:13:06 MySQL\_Thread.cpp:3631:process\_data\_on\_data\_stream(): [WARNING] Detected broken idle connection on 20.170.28.206:3306 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:56252 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:56264 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:36140 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:36126 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:36138 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:38420 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:38422 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:38430 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:43006 2024-02-07 11:13:06 MySQL\_Thread.cpp:3631:process\_data\_on\_data\_stream(): [WARNING] Detected broken idle connection on 20.170.29.122:3306 2024-02-07 11:13:06 MySQL\_Thread.cpp:3631:process\_data\_on\_data\_stream(): [WARNING] Detected broken idle connection on 20.170.28.206:3306 2024-02-07 11:13:06 MySQL\_Thread.cpp:3631:process\_data\_on\_data\_stream(): [WARNING] Detected broken idle connection on 20.170.29.122:3306 2024-02-07 11:13:06 MySQL\_Thread.cpp:3631:process\_data\_on\_data\_stream(): [WARNING] Detected broken idle connection on 20.170.29.122:3306 2024-02-07 11:13:06 MySQL\_Thread.cpp:3631:process\_data\_on\_data\_stream(): [WARNING] Detected broken idle connection on 20.52.153.225:3306 2024-02-07 11:13:06 MySQL\_Thread.cpp:3631:process\_data\_on\_data\_stream(): [WARNING] Detected broken idle connection on 20.52.153.225:3306 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:58736 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:56240 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:56262 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:42998 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:43004 2024-02-07 11:13:06 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:43024 2024-02-07 11:13:33 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:51450 2024-02-07 11:13:36 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:51452 2024-02-07 11:13:38 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:51462 2024-02-07 11:13:43 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:42572 2024-02-07 11:13:48 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:42590 2024-02-07 11:14:11 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:50452 2024-02-07 11:14:13 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:50424 2024-02-07 11:14:18 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:50442 2024-02-07 11:14:31 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:52808 2024-02-07 11:14:33 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:45366 2024-02-07 11:14:47 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:36100 2024-02-07 11:14:51 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:36124 how to solve above issue any one help me ---
**Author:** ![Mughees\_Ahmed](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/mughees_ahmed/32/9028_2.png) [@Mughees\_Ahmed](https://forums.percona.com/u/Mughees_Ahmed)\ **Post date:** [February 7, 2024, 11:48am UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/11 "2024-02-07T11:48:42Z")
> [@Santhosh\_Pandi](#): > > mysql-max\_connections reached. Returning ‘Too many connections’ please configure mysql-max\_connections to same as MySQL db , if all three nodes are reader that mean writer is also writer, I belive you might have set max\_connection in proxysql host group as 1000 so for each node proxysql is able to create 1000 connection so set mysql-max\_connections=4000 on proxysql and max\_connections=4000 on MySQL db . thanks obviously laod and save proxysql variable to runtime and disks ---
**Author:** ![Santhosh\_Pandi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/santhosh_pandi/32/11021_2.png) [@Santhosh\_Pandi](https://forums.percona.com/u/Santhosh_Pandi)\ **Post date:** [March 19, 2024, 6:27am UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/12 "2024-03-19T06:27:45Z")
[quote=“Santhosh\_Pandi, post:10, topic:28290”] 2024-02-07 11:14:33 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:45366 2024-02-07 11:14:47 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:36100 2024-02-07 11:14:51 MySQL\_Thread.cpp:3939:process\_all\_sessions(): [WARNING] Closing unhealthy client connection 20.113.158.117:36124 [/quote Any one facing this issue ---
**Author:** ![Shah\_Harshil\_Kiranku](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/shah_harshil_kiranku/32/19932_2.png) [@Shah\_Harshil\_Kiranku](https://forums.percona.com/u/Shah_Harshil_Kiranku)\ **Post date:** [December 29, 2025, 9:56am UTC](https://forums.percona.com/t/facing-connection-closure-issues-with-percona-mysql-and-proxysql-load-balancing/28290/13 "2025-12-29T09:56:44Z")
Hii @Santhosh_Pandi I am also facing the same issue on ProxySQL, but I am getting little different error. Error: **MySQL\_Thread.cpp:4126:ProcessAllSessions\_Healthy0(): [WARNING] Closing unhealthy client connection** How to solve this issue? ![image](https://us1.discourse-cdn.com/flex019/uploads/percona1/original/3X/1/7/17aa6b3167769b63e7605068d9667de191b5cc97.jpeg)