Re: How to optimize/defragment RAM usage of mysqld
Posted by:
Rick James
Date: February 20, 2016 12:13AM
Main memory (RAM) is managed by the OS in 4KB "pages". Any page can be anywhere in your 48GB. Every page is equally accessible. (NUMA notwithstanding.) Your software is (presumably) "64-bit. Hence, there is no such thing as "fragmentation" in RAM. Period. Full stop.
38G buffer_pool in 48GB of RAM should be fine. (I say 70% because that is safer when I don't know how much RAM a user has. Your 80% should not be a problem on a server dedicated to MySQL.)
Defragmentation on disk _may_ have _some_ benefit for _spinning_ drives. It is absolutely useless for SSDs.
If you would like further analysis of your settings, please provide SHOW VARIABLES; and SHOW GLOBAL STATUS;
If you are having performance problems, set long_query_time=1, turn on the slowlog, wait a day, then run pt-query-digest or mysqldumpslow -s t on the slowlog. The first couple of queries are usually the ones that can be fixed to give you a significant performance boost. Post another question if you need help with a query.
Subject
Views
Written By
Posted
1580
February 17, 2016 01:39AM
735
February 17, 2016 01:42AM
822
February 17, 2016 11:06AM
Re: How to optimize/defragment RAM usage of mysqld
977
February 20, 2016 12:13AM
719
February 22, 2016 05:49AM
Sorry, you can't reply to this topic. It has been closed.
Content reproduced on this site is the property of the respective copyright holders.
It is not reviewed in advance by Oracle and does not necessarily represent the opinion
of Oracle or any other party.