[mythtv-users] Very slow mythfrontend, mysql at 100%

[Michael T. Dean]

On 11/21/2009 05:42 PM, Ronald Pijnacker wrote:
>> On Fri Nov 20, 2009 at 03:00:16PM +0100, Ronald Pijnacker wrote:
>>     
>>> Since the wiki page discourages partial restores and I wasn't in the mood
>>> to reconfigure my systems, I tried just doing a backup/restore.
>>> I compared the first backup with a second (after restore) with identical results.
>>> But still somehow this managed to make the problem go away!
>>>       
>> Are you running the optimize_mythdb.pl script on a regular basis?  If
>> not, the backup/restore would have done many of the same
>> cleanups/optimisations as this script.
>>     
>
> No, I not doing this. However would you expect that the output of the database-backup
> script would be identical before and after restoring it?
> I'm not that knowledgable about databases, but I would think that with the same (exactly)
> output there would be no difference...

The optimize_mythdb.pl script doesn't fix or even change data.  All 
that's in a backup is data.  So the backups should look the same 
before/after.

The optimize_mythdb.pl script tells the DB to repair crashed tables, fix 
up/update indices, and compress the on-disc storage area allocated for 
the database.

Similarly, dropping the DB and restoring a backup will re-create indices 
(which means they're all fixed up and updated) and will write the data 
without any space/garbage in the middle, so...

Mike