# PMM tool open table and open cache miss ratio tune

**URL:** <https://forums.percona.com/t/pmm-tool-open-table-and-open-cache-miss-ratio-tune/17243>\
**Category:** Other MySQL® Questions\
**Tags:** pmm, mysql, percona\
**Created:** [September 1, 2022, 4:49am UTC](https://forums.percona.com/t/pmm-tool-open-table-and-open-cache-miss-ratio-tune/17243 "2022-09-01T04:49:45Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Pavanmysql](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/pavanmysql/32/7152_2.png) [@Pavanmysql](https://forums.percona.com/u/Pavanmysql)\
**Post date:** [September 1, 2022, 4:49am UTC](https://forums.percona.com/t/pmm-tool-open-table-and-open-cache-miss-ratio-tune/17243/1 "2022-09-01T04:49:45Z")

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Hi Percona Team,

Does i need to tune any MySQL related parameter as PMM shows below graph in red color (Percentage of open table definitions to table definition cache and open cache miss ratio)?

 ![Percentage_of_open_table](https://us1.discourse-cdn.com/flex019/uploads/percona1/original/2X/3/3132fb53496d1836482695831dc1a4e831ac8a87.jpeg)

 ![open_Cache_miss](https://us1.discourse-cdn.com/flex019/uploads/percona1/original/2X/6/691c36f54cdb7999df2fd19292483bd439b99599.jpeg)

How to tune this?

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<div class="post-metadata">

**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:** [September 1, 2022, 3:52pm UTC](https://forums.percona.com/t/pmm-tool-open-table-and-open-cache-miss-ratio-tune/17243/2 "2022-09-01T15:52:32Z")

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Try doubling your `table_open_cache` and try `table_open_cache_instances=24`