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Can replicating between versions cause crashed tables?
Posted by: Cody Konior
Date: February 23, 2009 09:10PM


We have a production server running an older version of MySQL 4.0 on OpenBSD. We don't have the expertise to upgrade the version on that server, and were actually wanting to decommission MySQL from that server and move it onto a Windows server.

As part of this, I took the database down one night and mysqldump'd the data, and then imported it into a MySQL 4.0 database on Windows. Then I dumped and imported again through versions 4.1, 5.0, and 5.1.

I wasn't sure if I was meant to do it through every version like that but it's what the documentation seemed to recommend ...

Then I set up MySQL 4.0 to replicate to the 5.1 server with --binlog and everything seemed to be okay for the past two weeks. We only use very simple queries ... the errors in the logs we got were relating to INSERT and UPDATE commands on strings that were too long for the original database (4.0 just truncates, 5.1 gives an error). So on the 5.1 machine I made those fields longer. No other errors occurred, and all the data was being shown in both databases.

I was satisfied it was working, so that night I was going to turn off the 4.0 database and switch everything over to the 5.1 database, when I started to get errors on the 5.1 server, specifically a few of the most frequently used tables were reporting that they were crashed and should be repaired.

When I repaired them, I found the record counts different to the master server, so I aborted the switchover until I decide what's going on. It appears at the very least the data needs to be completely re-extracted.

My question is:
Could replicating between versions have caused the tables to crash?
Could extending the fields on one server and not the other have caused the tables to crash?
(And this isn't the right group but) Do I really need to go through all those versions again or is it safe to dump from 4.0 into 5.1?

If it's purely a replication issue, I'll re-extract through all the versions and do the switchover in a single night. I'm just a little worried there's some other issue causing the tables to crash that will take out or valuable data once I switch it over ...


Edited 1 time(s). Last edit at 02/23/2009 09:59PM by Cody Konior.

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Can replicating between versions cause crashed tables?
February 23, 2009 09:10PM

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