# Need help with mysql configuration

**URL:** <https://forums.percona.com/t/need-help-with-mysql-configuration/27302>\
**Category:** Percona XtraDB Cluster 8.x\
**Created:** [December 21, 2023, 11:57am UTC](https://forums.percona.com/t/need-help-with-mysql-configuration/27302 "2023-12-21T11:57:55Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![elkhedewy](https://avatars.discourse-cdn.com/v4/letter/e/5fc32e/32.png) [@elkhedewy](https://forums.percona.com/u/elkhedewy)\
**Post date:** [December 21, 2023, 11:57am UTC](https://forums.percona.com/t/need-help-with-mysql-configuration/27302/1 "2023-12-21T11:57:55Z")

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Hello,

I’ve xtradb cluster version 8.0 and i am using mysqltuner script to enhance the performance. Now i’ve the below message from mysqltuner…Can some one explain what to do?

> General recommendations:  
> Run OPTIMIZE TABLE to defragment tables for better performance  
> Restrict Host for user@% to user@SpecificDNSorIp  
> Reduce your overall MySQL memory footprint for system stability  
> Adjust your join queries to always utilize indexes  
> Increase table\_open\_cache gradually to avoid file descriptor limits  
> Read this before increasing table\_open\_cache over 64: [http://bit.ly/1mi7c4C](http://bit.ly/1mi7c4C)  
> Beware that open\_files\_limit (16364) variable  
> should be greater than table\_open\_cache ( 1024)  
> Variables to adjust:  
> \*\*\* MySQL’s maximum memory usage is dangerously high \*\*\*  
> \*\*\* Add RAM before increasing MySQL buffer variables \*\*\*  
> query\_cache\_size (\>= 8M)  
> join\_buffer\_size (\> 16.0M, or always use indexes with joins)  
> table\_open\_cache (\> 1024)  
> innodb\_buffer\_pool\_instances(=3)

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**Author:** ![matthewb](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/matthewb/32/34_2.png) [@matthewb](https://forums.percona.com/u/matthewb)\
**Post date:** [December 22, 2023, 4:59pm UTC](https://forums.percona.com/t/need-help-with-mysql-configuration/27302/2 "2023-12-22T16:59:05Z")

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Hello @elkhedewy,  
Each one of those lines tells you what to do. There’s a lot there. OPTIMIZE TABLE will rebuild a table to remove empty free space; users with ‘%’ are considered a security risk; MySQL might be using too much memory so you’ll need to lower max\_connections or reduce buffer pool size; optimize your queries (that’s a whole huge topic).  
If you want more specific recommendations beyond what mysqltuner is telling you, I recommend you engage our [support team](https://percona.com/services/support). They can provide the specific commands/recommendations to you based on better evidence than this simple perl script.