Adam Donnison's Blog

April 23, 2012

Using the MySQL stack trace to isolate bugs

I came across an interesting error reported on #mysql the other day. When I went through it with the reporter it looks like we uncovered up to two bugs in InnoDB (or rather XtraDB as it was Percona Server). I thought it might be useful to go through the error message, including the stack trace, to show that you don't need to be a developer to track down some useful information. If you look at http://pastie.org/3836611 you'll see the error message.

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September 09, 2011

Client requested master to start replication from impossible position

If you run a replicated MySQL setup and have a master failure, you may see the following error in your error log.

[ERROR] Error reading packet from server: Client requested master to start replication from impossible position ( server_errno=1236) 

At this point your slave will not be replicating and you will need to recover from the situation. But why did it occur in the first place and what does it mean to your data integrity?

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