Today we had a very interesting phenomena at a customer. He complained that MySQL always get some errors of the following type:
[ERROR] mysqld: Sort aborted: Error writing file '/tmp/MYGbBrpA' (Errcode: 28 - No space left on device)
After a first investigation we found that df -h /tmp
shows from time to time a full disk but we could not see any file
with ls -la /tmp/MY*.
After some more investigation we found even the query from the Slow Query Log which was producing the same problem. It looked similar to this query:
SELECT * FROM test ORDER BY field5, field4, field3, field2, field1;
Now we were capable to simulate the problem at will with the following table:
CREATE TABLE `test` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `data` varchar(64) DEFAULT NULL, `ts` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE …[Read more]