# High SEMAPHORES from the time upgraded to 5.6

**URL:** <https://forums.percona.com/t/high-semaphores-from-the-time-upgraded-to-5-6/3724>\
**Category:** Other MySQL® Questions\
**Created:** [September 5, 2014, 8:38am UTC](https://forums.percona.com/t/high-semaphores-from-the-time-upgraded-to-5-6/3724 "2014-09-05T08:38:44Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![infdude666](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/infdude666/32/11425_2.png) [@infdude666](https://forums.percona.com/u/infdude666)\
**Post date:** [September 5, 2014, 8:38am UTC](https://forums.percona.com/t/high-semaphores-from-the-time-upgraded-to-5-6/3724/1 "2014-09-05T08:38:44Z")

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Hi recently upgraded 5.5 to 5.6 and have noticed High SEMAPHORES round, waits, os waits.

Im unsure of why this is happening.

Please help

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<div class="post-metadata">

**Author:** ![niljoshi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/niljoshi/32/16889_2.png) [@niljoshi](https://forums.percona.com/u/niljoshi)\
**Post date:** [September 11, 2014, 11:42pm UTC](https://forums.percona.com/t/high-semaphores-from-the-time-upgraded-to-5-6/3724/2 "2014-09-11T23:42:22Z")

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Hi,

Can you provide some more information? like

1. steps you have taken while upgrade your server from 5.5 to 5.6?
2. Error log
3. Give exact version of 5.5 and 5.6 (i.e 5.5.x to 5.6.x)

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<div class="post-metadata">

**Author:** ![infdude666](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/infdude666/32/11425_2.png) [@infdude666](https://forums.percona.com/u/infdude666)\
**Post date:** [September 19, 2014, 3:03am UTC](https://forums.percona.com/t/high-semaphores-from-the-time-upgraded-to-5-6/3724/3 "2014-09-19T03:03:20Z")

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Also im seeing frequent stalls with queries taking more time than milliseconds, even commit’s.

Steps.  
Shutdown mysql;  
remove old version 5.5.29 via yum remove  
install new version 5.6.19 via yum install  
run mysql\_upgrade  
change TEMPORAL Columns for Datatime with ALTER FORCE.

I have RAID 10 with BBU, 2 CPU with 16cores, 32(virtual), 32 GB RAM

my.cnf  
innodb\_buffer\_pool\_instances=2  
innodb\_buffer\_pool\_size=22G  
innodb\_flush\_log\_at\_trx\_commit=2  
innodb\_flush\_method=O\_DIRECT  
innodb\_io\_capacity=800  
innodb\_log\_file\_size=1G  
innodb\_log\_files\_in\_group=2  
innodb\_purge\_threads=1  
innodb\_read\_io\_threads=12  
innodb\_write\_io\_threads=12  
innodb\_thread\_concurrency=0  
table\_open\_cache=2000  
table\_definition\_cache=4096  
query\_cache\_limit=64M  
query\_cache\_size=128M  
query\_cache\_type=1  
query\_cache\_strip\_comments=1  
relay\_log\_info\_repository=TABLE  
relay\_log\_recovery=ON  
master\_info\_repository=TABLE  
thread\_stack = 256K

The list was big and couldnt paste or attach:

SHOW ENGINE MUTEX:  
[URL][http://pastebin.com/F8XfyL7r[/URL]](http://pastebin.com/F8XfyL7r%5B/URL%5D)