Percona 5.6 high memory usage

Question

I'm not sure if stack is the right place to ask this, but I recently upgraded to Percona 5.6 from 5.5 and my memory usage has skyrocketed!

This is from PS:

mysql     4598  0.0 29.5 1583356 465312 ?      Sl   Oct17   9:07 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib6

I'm on a dedicated VSS

My server only has a gig of ram...how is this only memory usage only 30% according to PS?

I have my ram set in the config to be less than this, and when I run MySQLTuner i get:

[OK] Maximum possible memory usage: 338.9M (22% of installed RAM)

So how am I using almost 500MB of physical memory and over a gig and a half of virtual?

Is this a bug in mySQL or something with my server?

Answer 1

found out that in mysql 5.6 performance_schema is on by default. It was disabled by default prior in 5.5 and before. It has been enabled by default since 5.6.6

performance_schema=off to my config file fixes the issue.

I'd imagine anyone who doesn't have the memory to be running performance_schema would not be using it anyway.

This might affect other distros of mysql 5.6.6 as well.

Answer 2

I had this problem and fixing a few (increased) cache values in MySQL.ini sorted the problem out.

table_definition_cache - set to 400

From "http://bugs.mysql.com/bug.php?id=68287" where this is discussed

Yes, there are thresholds based on table_open_cache and table_definition_cache and max_connections and crossing the thresholds produces a big increase in RAM used. The thresholds work by first deciding if the server size is small, medium or large.

Small: all three are same as or less than defaults (2000, 400, 151). Large: any of the three is more than twice the default. Medium: others.

From memory. mine was set to 2000+ and dropping it sorted the problem.

Answer 3

What helped me was on CentOS was changing the memory allocator:

yum install jemalloc-devel

and add to my.cnf:

[mysqld_safe]

malloc-lib = /usr/lib64/libjemalloc.so.1