MySQL Error caused by Mappress?

[ckrauskopf]

We’ve had a sudden slowdown of our entire site, and intermittently people have seen an error message referencing wp_mappress_maps and wp_mappress_posts tables.  I’ve posted a link to the screenshot of that error taken by the person who got it, but I have not been able to replicate it myself.

It says that the MySQL Server has gone away, and then references the mappress tables:

http://dl.dropbox.com/u/395323/mappress_error.png

The whole thing doesn’t make much sense to me, starting with the fact that the page where the error was seen has no mappress maps on it.  In fact, Mappress is not even enabled on that post type, so why there would be any issue with mappress tables when loading that particular page is beyond me.

I used phpadmin to verify that those tables are there, and I didn’t see any extra entries for posts that shouldn’t have maps, but I don’t know what else to do.  I am using plugin v 2.40 PRO with wp v 3.5.

Our host, MediaTemple doesn’t seem to think the problem is on them, and are telling us that the slowdown of our entire site could be caused by corrupted MapPress tables.  That sounds like passing the buck, but I’d really appreciate any help you can provide.

 

 

[Chris]

Hi,

I’m not sure I can help resolve that problem, but I can give you some background info.

When MapPress is loaded it checks that its tables are present and, if not, it creates them (even if there are no maps to display).  Apparently when it checked, the database didn’t respond.

I believe the ‘MySQL has gone away’ error occurs when the server has lost its connection to the database or the database is very slow in responding.

I assume that could be caused by a server problem or a database issue.  Corrupted tables sounds plausible but it’s too bad MT wasn’t able to help you pinpoint it more exactly.

Here’s the MySQL manual page for the error in case it’s helpful:

http://dev.mysql.com/doc/refman/5.0/en/gone-away.html

Increasing the timeout values might fix the error but I’m not sure they would speed things up.  If you think it’s corrupted tables you could try rebuilding or repairing the database:

http://dev.mysql.com/doc/refman/5.0/en/rebuilding-tables.html

 

[ckrauskopf]

Thanks for the quick reply.  It was helpful.  I have a couple of clarification questions to make sure I understand your response.

1a)  If it is a corrupted table that is causing the slow loads and ultimate loss of database connection, do I understand correctly that it could it be a non MapPress table that is corrupted even though the error comes from MapPress?  Any thing that caused the database connection to be lost would result in MapPress trying to recreate it’s tables and thus cause the error – is that right?

 

1b) In fact, in the cases where the page does finally load and there is a map, that map seems to display correctly.  Would you say that this is an indication that the MapPress tables are intact?

2) I’m  still surprised that this error is occurring on pages/posts types where the MapPress settings don’t even make MapPress an option.  I have MapPress limited to 2 custom post types, yet this occurs on normal posts and pages too.  Does that mean that MapPress makes calls to the database every time any page on the site is loaded, no matter what I do in the settings?

Thanks again for the quick help.

[Chris]

Hi,

1) The error comes from MapPress because it issues a database command to check for a table (see #2).  The error is just a symptom of the real problem – which is that the server lost its connection to the database – it’s not an indication that the error has anything to do with MapPress or that specific table.

1b) Probably

2) WordPress loads every plugin for every page.  When MapPress is loaded it checks that its table exists, whether or not it’s displaying a map.  That’s why you see an error on pages without a map.

 

[ckrauskopf]

Thanks for your help Chris.  We’ll try to troubleshoot the connection issue with Media Temple.  I think this info will be helpful in that process.

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