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i ran out of disk space while running an alter table on a large table. I restarted MySQL afterwards and checked the MySQL tmp dir. A show status like '%tmp%' lists 5 tmp files and 4 tmp tables. A df still shows 99% disk usage (was like 72% before the alter table).

Running a "check table" returns "OK".

How to clean up the disk space used by the alter table command?

I'm running MySQL 5.5.31 on Ubuntu 12.04.

Thanks: Lars

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you can use some ram partition for tmptable instead of hdd, this can be better for space and performance – user973254 Nov 8 '13 at 20:23
Unfortunately the server only has 8 GB ram and i assume MySQL needs like 20 GB to complete the alter table process. – bitrocker Nov 9 '13 at 21:20

Common approach to find where your space has gone.

  1. check for explicit files disk usage with du -ms /path/*.
  2. check "hidden" open files disk usage with lsof | grep deleted | grep /path
  3. last resort: check the file-system consistency.
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I just mentioned InnoDB in the tags, sorry. There are no tmp files, it's just InnoDB's ibdata file that now is 40 GB. – bitrocker Nov 9 '13 at 21:22
Ok in that case a usefull link for you:… – Veniamin Nov 10 '13 at 7:36

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