The Ultimate Guide to High Availability with MariaDB

Comments - Incredibly slow count(*) on MariaDB / MySQL

7 months, 3 weeks ago Ian Gilfillan
Re: Incredibly slow count(*) on MariaDB / MySQL [Answer]

With InnoDB, since it only stores estimates of the number of rows in the table, in order to obtain the specific value with COUNT(*), all rows need to be read, which is very slow.

If you're happy with an estimate, you can query information_schema.tables, for example:

SELECT TABLE_ROWS FROM information_schema.tables
WHERE TABLE_SCHEMA = 'db_name' 
AND TABLE_NAME = 'table_name';

See also MDEV-18188.

 
7 months, 3 weeks ago Michael Modan
Re: Incredibly slow count(*) on MariaDB / MySQL

Thank you for your comment Ian. Meaning if I'd turn this to use MyISAM it'd work faster?

I'll test it and revert with results :)

Yes, I'm aware of the estimate option via table_rows - can I control its update frequency / ratio i.e if i run ANALYZE TABLE [table_name] periodically does it update the stats?

 
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