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[EP-tech] Re: mysqldump problem with cachetables



If you are running myisam table engine, you could try myisamchk (http://dev.mysql.com/doc/refman/5.0/en/myisamchk.html) to check for underlying table problems.

Is it possible that EPrints is cleaning up (dropping) cache tables while mysqldump is running?

Mark

Mark Gregson | Applications and Development Team Leader
Library eServices | Queensland University of Technology
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-----Original Message-----
From: eprints-tech-bounces at ecs.soton.ac.uk [mailto:eprints-tech-bounces at ecs.soton.ac.uk] On Behalf Of Malcolm Bodger
Sent: Saturday, 20 April 2013 12:19 AM
To: paolo.tealdi at polito.it
Cc: <eprints-tech at ecs.soton.ac.uk>
Subject: [EP-tech] Re: mysqldump problem with cachetables

Hi Paolo,

I'm running mysqldump with the force option and I have 15 lines of error mesages, like this one:

Error: Couldn't read status information for table cache1813265 ()
mysqldump: Couldn't execute 'show create table `cache1813265`': Table 'eprints.cache1813265' doesn't exist (1146)

Can I ignore these errors?

Thanks.
Regards,
Malcolm.
________________________________________
From: Malcolm Bodger
Sent: 19 April 2013 15:07
To: paolo.tealdi at polito.it
Cc: <eprints-tech at ecs.soton.ac.uk>
Subject: RE: [EP-tech]  mysqldump problem with cachetables

Hi Paolo,

Thanks for this information, it's very helpful, and I'll go with the 'force' option.

Regards,
Malcolm.
________________________________________
From: Paolo Tealdi [paolo.tealdi at polito.it]
Sent: 19 April 2013 14:23
To: Malcolm Bodger
Cc: <eprints-tech at ecs.soton.ac.uk>
Subject: Re: [EP-tech]  mysqldump problem with cachetables

Il 19/04/2013 15:01, Malcolm Bodger ha scritto:
> Hi Paolo,
>
> I run the cleanup_cachemaps, but it only removed one orphaned table, leaving me with 942.
> Would you know why I have so many cache tables?
>
> Thanks.
> Regards,
> Malcolm.
>

Hi Malcom,
This is normal.
When you make a web search on your eprints web interface, the system saves the result records in a cache table, avoiding to repeat a (possibly) cpu intensive operation (for example to present the next search page).
The server saves the recordset result in a table named "cache$number" and adds a line also in "cachemap" table.
The epadmin command i wrote matches the records in "cache" table with the cache"number" table,  cleaning orphaned table (NOT all cache table on the orphaned one).
The server has a setting for the max number of cache table active, when you go beyond that number, automatically the server drops the oldest table "table$number" and deletes its related record in "cachemap" table.
The error you find in the mysqldump is due to this automatic cache cleaning by eprints: mysqldump tries to dump a table that eprints has already deleted.
I think it's not a problem if you put --force in the mysqldump parameters.


Best regards,
Paolo Tealdi


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