[mythtv-users] mysql filling up hard drive

[Dan Wilga]

On 5/8/15 2:00 PM, Scott Moncrieff wrote:
> Apologies for the misinformation, it was nothing to do with the 
> ssh-agent file. The computer was not responding so the directory did 
> not update.
>
> When the disk starts to fill up, 6 files appear in /tmp
> #sql_4ec_0.MYD
> #sql4ec_2a3_0.frm
> #sql4ec_2a3_0.MYI
> #sql4ec_2a3_1.MYD
> #sql_4ec_0.MYI
> #sql4ec_2a3_0.MYD
> #sql4ec_2a3_1.frm
> #sql4ec_2a3_1.MYI
These are temporary files created by MySQL during large queries that 
have more results than can be stored in the RAM allotted to it. 
Depending on the query, this could easily fill up a hard drive.

If you have not already tuned MySQL, you should look into the settings 
available in /etc/my.cnf. The most relevant ones in your case would 
probably be tmp_table_size and max_heap_table_size which, for MyISAM 
tables, should probably be identical. I use a value of 500M for each, 
which means large queries that cannot be satisfied by other caching 
methods can take up to 500 Mb before having to be written to disk.

If you have enough free RAM, you could set tmpdir to /dev/shm/, but this 
is a less efficient way of doing the same thing.
>
> I have cut out the middle of large sections of similar data for 
> clarity but the drive starts to fill up after the line:
>
> GetPlaybackURL/UNABLE/TO/FIND/LOCAL/FILE/ON/MythtvServer/9703_20150222193800.mpg. 
> File doesn't exist.  Database metadata will not be removed.
This is most likely just a symptom of the drive already being full.
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