# open file limit - Table cache

**URL:** <https://forums.percona.com/t/open-file-limit-table-cache/1180>\
**Category:** Other MySQL® Questions\
**Created:** [May 27, 2009, 2:45am UTC](https://forums.percona.com/t/open-file-limit-table-cache/1180 "2009-05-27T02:45:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kedarpercona](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/kedarpercona/32/809_2.png) [@kedarpercona](https://forums.percona.com/u/kedarpercona)\
**Post date:** [May 27, 2009, 2:45am UTC](https://forums.percona.com/t/open-file-limit-table-cache/1180/1 "2009-05-27T02:45:37Z")

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I don’t have dedicated mysql server - its LAMPP with php app running on the same machine.

Below is mysqltuner result.

-------- General Statistics --------------------------------------------------  
[–] Skipped version check for MySQLTuner script  
[OK] Currently running supported MySQL version 5.0.27-log  
[!!] Switch to 64-bit OS - MySQL cannot currently use all of your RAM

-------- Storage Engine Statistics -------------------------------------------  
[–] Status: +Archive -BDB -Federated -InnoDB -ISAM -NDBCluster  
[–] Data in MyISAM tables: 19G (Tables: 491)  
[–] Data in ARCHIVE tables: 28B (Tables: 1)  
[!!] Total fragmented tables: 18

-------- Performance Metrics -------------------------------------------------  
[–] Up for: 37d 1h 9m 12s (1B q [481.357 qps], 1M conn, TX: 2B, RX: 2B)  
[–] Reads / Writes: 36% / 64%  
[–] Total buffers: 1.1G global + 13.2M per thread (100 max threads)  
[!!] Allocating \> 2GB RAM on 32-bit systems can cause system instability  
[!!] Maximum possible memory usage: 2.4G (60% of installed RAM)  
[OK] Slow queries: 0% (25K/1B)  
[OK] Highest usage of available connections: 79% (79/100)  
[OK] Key buffer size / total MyISAM indexes: 1.0G/2.2G  
[OK] Key buffer hit rate: 99.7% (26B cached / 67M reads)  
[OK] Query cache efficiency: 57.9% (5M cached / 9M selects)  
[OK] Query cache prunes per day: 0  
[OK] Sorts requiring temporary tables: 0% (35 temp sorts / 227M sorts)  
[!!] Joins performed without indexes: 14973  
[OK] Temporary tables created on disk: 11% (134K on disk / 1M total)  
[OK] Thread cache hit rate: 99% (462 created / 1M connections)  
[!!] Table cache hit rate: 0% (500 open / 94K opened)  
[OK] Open file limit used: 82% (849/1K)  
[OK] Table locks acquired immediately: 99% (123M immediate / 123M locks)

-------- Recommendations -----------------------------------------------------  
General recommendations:  
Run OPTIMIZE TABLE to defragment tables for better performance  
Adjust your join queries to always utilize indexes  
Increase table\_cache gradually to avoid file descriptor limits  
Variables to adjust:  
join\_buffer\_size (\> 1.0M, or always use indexes with joins)  
table\_cache (\> 500)

* * *

I see a biggest problem here is Table cache hit rate: 0% !  
I have open files limit of 1024 on ubuntu.  
I couldn’t set table\_cache \>650 as trying above that creates problems as others are there to use the system !!

How can i consider increasing open files limit?  
What is required to check before doing that ?

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**Author:** ![pwlnw](https://avatars.discourse-cdn.com/v4/letter/p/4af34b/32.png) [@pwlnw](https://forums.percona.com/u/pwlnw)\
**Post date:** [May 31, 2009, 1:57am UTC](https://forums.percona.com/t/open-file-limit-table-cache/1180/2 "2009-05-31T01:57:26Z")

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this is known bug.

[https://bugs.launchpad.net/ubuntu/+source/mysql-dfsg-5.0/+bu](https://bugs.launchpad.net/ubuntu/+source/mysql-dfsg-5.0/+bu) g/306541  
remove apparmor package OR upgrade to Jaunty, OR install new ourdelta builds