Re: Mysql memory usage increasing until it hits the RAM limit and starts using swap

[Peter Brawley]

Re "bug2" on that page we find ...

"We're facing a similar issue like this while using MySQL 5.7.18 Community edition in our CentOS 7 systems(CentOS Linux release 7.3.1611 (Core), Linux 172.20.19.194 3.10.0-514.26.2.el7.x86_64).

"After many concurrent connections to the server, there seems a substantial increase in the amount of memory being used by mysql process & eventually results in OS crash due to memory overflow. Think, the memory allocated for each connection(s) are not set to free properly.

"So, we tried using the TCMalloc(http://goog-perftools.sourceforge.net/doc/tcmalloc.html) for memory allocation. We found the memory is under control & everything seems normal after that."

... (emphasis added) so I'd want to pursue that despite https://dev.mysql.com/doc/refman/5.7/en/mysqld-safe.html#option_mysqld_safe_malloc-lib

Re how much RAM, I'd try one thing at a time, first fix the queries requiring scans & temp tables and adjust settings so there's RAM headroom, second the mem alloc options above. Then when it's reasonably optimised, I'd increase RAM by 50-100% depending on what size of request is likely to make a beancounter's head explode.

I agree about partitioning.

Re hardware I'd start with RAM.



Edited 1 time(s). Last edit at 12/11/2018 08:16PM by Peter Brawley.