1 Topic by mko

  • mko
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  • From: sf, ca
  • Registered: 2005-03-23
  • Posts: 14

Topic: Multiple servers, mysql woes

Everything seemed to be running just in our loadbalanced, multiple server test, but now that we've migrated the databases and have a few days of real use on it, something seems to be croaking.

* The scripts are updating the database accordingly
* All cache directories are 777
* The cache seems to be the source of some of the problems.

1. when i log in, sometimes it tells me (& other users) that my password is incorrect... other times it logs in w/o issue.

2. when a setting is changed in the admin/options menu, I get similar behavior... sometimes it goes right through, other times it tells me that the cache directory isn't writeable by php (confused - double checked cache directories)

3. I'm unable to disable the boards... the database is correct, but it doesn't seem to work.

4. I've tried clearing the cache directories on each of the machines to no avail.

5. SQL queries that I don't understand are remaining in the process list & seemingly stalling the database machine.  This is what phpmyAdmin looks like:
http://www.musicamang.com/other/sql_issues.gif

6. Any help would be MUCH appreciated... i'm struggling to even disable the board at this point sad

7. btw, the board was running fine over the weekend... just started to barf this morning... any thoughts?

thanks.

- mko

forums are fun

2 Reply by mko

  • mko
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  • From: sf, ca
  • Registered: 2005-03-23
  • Posts: 14

Re: Multiple servers, mysql woes

Is there anything I can provide that would help you assist with this issue - just name it.
thanks.

forums are fun

3 Reply by Frank H (edited by Frank H 2005-07-26 18:39)

  • Frank H
  • Former PunBB Developer
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  • Registered: 2003-03-16
  • Posts: 1,423

Re: Multiple servers, mysql woes

are the server out of memory? (if so, what's taking up most of the memory?) ... could be cured by limiting the number of mysql threads, and php threads allowed to start (and their respective memory usage could be lowered ... but it's really not a good way IMO)

also, on a vbulletin board I visit frequently, they had issues where the forum just died, it was due to bugs in php (and there wasn't any appropiate version to change to due to security issues) ... they just restarted it now and then ...

I also had an issue myself when I ran RedHat, after several days of running fine, it just slowed down and died (didn't respond to anything, not even when I plugged in the keyboard at the computer ... so I always had to restart it with the powerbutton ... after a while I got sick of trying to find the error and installed Debian Stable instead (as it took so long before any changes and the computer died))

  • From: 127.0.0.1
  • Registered: 2001-11-02
  • Posts: 9,167

Re: Multiple servers, mysql woes

Well, the most prominent query in the process list is the query that updates the views counter for topics. It's at the bottom of viewtopic.php. Try disabling it and see what happens. Since it's an update, it has a tendency to cause problems for MySQL since it only has table level locking in the MyISAM table type (every time it updates a row in the table, all other queries are put on hold). An alterantive would be to change the topics table to InnoDB.

"Programming is like sex: one mistake and you have to support it for the rest of your life."

Rickard's Website

5 Reply by wyen (edited by wyen 2005-07-28 00:33)

  • wyen
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  • Registered: 2005-06-27
  • Posts: 4

Re: Multiple servers, mysql woes

To give some more info, this new board we have was converted over from phpBB.  At the end of the conversion, there were some errors given by the converter tool, but all the topics and users were there, and passwords working fine.  We tested the new forum offline and it worked great.  I'm not sure if the converter did something to the database that would cause any problems.

An alterantive would be to change the topics table to InnoDB.

I will look into this.  Seems like a viable solution.  I remember when we had phpBB though, the topic views were updating fine, and MySQL had no problems timing out the processes that were updating the topic views.

As for the cache problem, any ideas?  I'm referring to this:

2. when a setting is changed in the admin/options menu, I get similar behavior... sometimes it goes right through, other times it tells me that the cache directory isn't writeable by php (confused - double checked cache directories)

3. I'm unable to disable the boards... the database is correct, but it doesn't seem to work.

Does this have anything to do with the fact that we are running the files on multiple servers?

Any further help on this much appreciated smile

  • From: 127.0.0.1
  • Registered: 2001-11-02
  • Posts: 9,167

Re: Multiple servers, mysql woes

I have no idea regarding the cache problem. Perhaps the updated cache php files are not properly propagated between the servers?

Regarding the conversion. You should make sure that the tables are properly indexed. I recommend that you install a fresh copy of PunBB in a different database and then compare the indexes. If one is missing, add it.

"Programming is like sex: one mistake and you have to support it for the rest of your life."

Rickard's Website