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Re: Performance problem migrating from NDB to MyISAM
Posted by: Rick James
Date: January 24, 2015 11:39AM

Also, moving to MyISAM is a step backward; move to InnoDB instead.

Specifically, the construct
is essentially not optimized and performs very poorly in 5.1. That construct in better optimized in 5.7(?). Meanwhile, turn it into a JOIN.

key_buffer_size (for MyISAM) and innodb_buffer_pool_size (for InnoDB) are not set to reasonable values -- this has a big impact. See

See the following for a number of tips on how to improve the schema when moving to InnoDB from MyISAM. Indirectly, it will give you some tips on your NDB->MyISAM migration:

Is this a true/false flag, or just a few small values? If so, use TINYINT (1 byte), not BIGINT (8 bytes):
`processed` bigint(20) unsigned NOT NULL DEFAULT '1'
And use UNSIGNED wherever appropriate.

> where from_unixtime(date) > date('2014-11-30')

Hiding a column (`date`) inside a function call (from_unixtime) prevents using any index on `date`. This has the same effect, and has more potential for efficient use of an index:
where date > '2014-11-30'

The tips we have given you could get you closer to 0.03 secs than 17 sec. However, it may take another pass (of reviewing your settings, schema, engine, version, select, etc) to get all the way to 0.03 sec.

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Re: Performance problem migrating from NDB to MyISAM
January 24, 2015 11:39AM

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