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Re: MyISAM - Large Memory Footprint
Posted by: Rick James
Date: July 31, 2010 11:54PM

key_buffer_size=8G --> 2G
The key_buffer is for index blocks only. When it is too large takes, it can take away from data caching, which is handled by the OS in the left over ram.

Since MyISAM does cache stuff, the is little or no advantage in using Engine=MEMORY.

Not much advantage in myisam_use_mmap, since the caching is already done.

To improve performance, let's get into the details; please provide
* SHOW CREATE TABLE tbl\G -- engine, indexes
* SHOW TABLE STATUS LIKE 'tbl'\G -- sizes
* EXPLAIN SELECT ...\G -- clues of inefficiencies
and surround them with [ code ] and [ / code ]

Look in the slowlog for some info.

innodb_buffer_pool_size=512M --> 0M (assuming you have no InnoDB)

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