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Re: slow queries and high % of wait I/O
Posted by: Rick James
Date: January 19, 2009 05:36PM

(Thanks for the schema and table status; these are often the most important clues in performance problems.)

Your table is nearly 4 times as big as innodb_buffer_pool_size. If you are on a 64-bit machine with more than 4GB of RAM, suggest you raise the size.

Is that one SELECT the main thing that is in the slowlog? And it is only once a second?

How random are device_ids? How many rows are returned for the SELECT? Does the slow log say "Rows examined" is about the same as "rows"? Or is it about the size of the table?

Plz SHOW VARIABLES LIKE 'innodb%'; there may be some more clues there.

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