>Sent: Monday, April 25, 2011 10:24 AM
>To: Mailing-List mysql
>Subject: Memory Usage.
>How can I know how memory is being used by Mysql?
>I have 32GB Ram, but I can't make mysql to use more than 12GB Ram , and even
>that I have tables over 40GB...
[JS] The amount of memory used will be the smallest of
1. Available physical memory
2. Usable memory (this is a limitation built into the code design, both at OS
level and at the MySQL/storage engine level)
3. Allowed memory (a configuration setting)
4. Needed memory
1 and 2 are usually easy to find out.
When it comes to 4, things get very murky. As someone else said, the goal is
to use memory wisely. That means finding a trade-off between efficient use of
memory and speed. Once you understand and make some choices with 4, you can go
back and tinker with 3.
As any performance consultant worth his salt will tell you, "It depends."
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