MySQL, Error 126: Incorrect key file for table

Question

I read the following question that has relevance, but the replies didn't satify me: MySQL: #126 - Incorrect key file for table

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The problem

When running a query I get this error

ERROR 126 (HY000): Incorrect key file for table`

The question

When I'm trying to find the problem I cant't find one, so I don't know how to fix it with the repair command. Is there any pointers to how I can find the problem causing this issue in any other way then I already have tried?

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The query

mysql>       SELECT     ->         Process.processId,     ->         Domain.id AS domainId,     ->         Domain.host,     ->         Process.started,     ->         COUNT(DISTINCT Joppli.id) AS countedObjects,     ->         COUNT(DISTINCT Page.id)   AS countedPages,     ->         COUNT(DISTINCT Rule.id)   AS countedRules     ->       FROM Domain     ->         JOIN CustomScrapingRule     ->           AS Rule     ->           ON Rule.Domain_id = Domain.id     ->           LEFT JOIN StructuredData_Joppli     ->             AS Joppli     ->             ON Joppli.CustomScrapingRule_id = Rule.id     ->         LEFT JOIN Domain_Page     ->           AS Page     ->           ON Page.Domain_id = Domain.id     ->         LEFT JOIN Domain_Process     ->           AS Process     ->           ON Process.Domain_id = Domain.id     ->       WHERE Rule.CustomScrapingRule_id IS NULL     ->       GROUP BY Domain.id     ->       ORDER BY Domain.host; ERROR 126 (HY000): Incorrect key file for table '/tmp/#sql_2b5_4.MYI'; try to repair it 

mysqlcheck

root@scraper:~# mysqlcheck -p scraper Enter password:  scraper.CustomScrapingRule                         OK scraper.Domain                                     OK scraper.Domain_Page                                OK scraper.Domain_Page_Rank                           OK scraper.Domain_Process                             OK scraper.Log                                        OK scraper.StructuredData_Joppli                      OK scraper.StructuredData_Joppli_Product              OK 

counted rows

mysql> select count(*) from CustomScrapingRule; +----------+ | count(*) | +----------+ |       26 | +----------+ 1 row in set (0.04 sec)  mysql> select count(*) from Domain; +----------+ | count(*) | +----------+ |        2 | +----------+ 1 row in set (0.01 sec)  mysql> select count(*) from Domain_Page; +----------+ | count(*) | +----------+ |   134288 | +----------+ 1 row in set (0.17 sec)  mysql> select count(*) from Domain_Page_Rank; +----------+ | count(*) | +----------+ |  4671111 | +----------+ 1 row in set (11.69 sec)  mysql> select count(*) from Domain_Process; +----------+ | count(*) | +----------+ |        2 | +----------+ 1 row in set (0.02 sec)  mysql> select count(*) from Log; +----------+ | count(*) | +----------+ |       41 | +----------+ 1 row in set (0.00 sec)  mysql> select count(*) from StructuredData_Joppli; +----------+ | count(*) | +----------+ |    11433 | +----------+ 1 row in set (0.16 sec)  mysql> select count(*) from StructuredData_Joppli_Product; +----------+ | count(*) | +----------+ |   130784 | +----------+ 1 row in set (0.20 sec) 

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Update

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Disk usage

root@scraper:/tmp# df -h Filesystem      Size  Used Avail Use% Mounted on /dev/xvda1       20G  4.7G   15G  26% / none            4.0K     0  4.0K   0% /sys/fs/cgroup udev            237M  4.0K  237M   1% /dev tmpfs            49M  188K   49M   1% /run none            5.0M     0  5.0M   0% /run/lock none            245M     0  245M   0% /run/shm none            100M     0  100M   0% /run/user 

Answer 1

It appears that your query is returning a large intermediate result set requiring the creation of a temporary table and that the configured location for mysql temporary disk tables (/tmp) is not large enough for the resulting temporary table.

You could try increasing the tmpfs partition size by remounting it:

mount -t tmpfs -o remount,size=1G tmpfs /tmp 

You can make this change permanent by editing /etc/fstab

If you are unable to do this you could try changing the location of disk temporary tables by editing the "tmpdir" entry in your my.cnf file (or add it if it is not already there). Remember that the directory you choose should be writable by the mysql user

You could also try preventing the creation of an on disk temporary table by increasing the values for the mysql configuration options:

tmp_table_size max_heap_table_size 

to larger values. You will need to increase both of the above parameters

Example:

set global tmp_table_size = 1G; set global max_heap_table_size = 1G;