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Re: Queries in Locked State
Posted by: Rick James
Date: September 30, 2011 06:50PM

MyISAM or InnoDB?

A JOIN between two tables could cause such a lock.

Do SHOW FULL PROCESSLIST when you get such a lock; then show us, plus

To assist in analyzing slow SELECTs, please provide
* SHOW CREATE TABLE tbl\G -- engine, indexes
* SHOW TABLE STATUS LIKE 'tbl'\G -- sizes
* EXPLAIN SELECT ...\G -- clues of inefficiencies
* SHOW VARIABLES LIKE '%buffer%'; -- cache size
and surround them with [ code ] and [ / code ]
How much RAM do you have?

In MyISAM, ...
* A write will stall until any reads on that table(s) are finished.
* A read will stall until any writes on that table(s) are finished.
* If you have replication, remember that writes are coming through the replication stream.

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