Comments on: How to know if a MySQL slave is identical to its master

By: mandm

mandm — Tue, 27 Jul 2010 16:38:11 +0000

Hi Xaprb,
I thought since you are the guru in this master-slave replication process i shall ask you all the details about the failure i am facing in this. i see a similar duplicate entry error as mentioned above? how do i go about resolving this error and is rebuilding the slave the only way out? where should i look for the errors?

please let me know if you need more details from me? thanks in advance

By: Xaprb

Xaprb — Wed, 31 Oct 2007 13:06:40 +0000

Whoops — I should give more info. You can use CHECK TABLE and/or REPAIR TABLE and related commands. Check the relevant section of the manual; it has a lot of info about table corruption and how to fix it.

By: Xaprb

Xaprb — Wed, 31 Oct 2007 13:05:15 +0000

Sounds like table or index corruption on the slave.

By: Tim H

Tim H — Wed, 31 Oct 2007 12:59:08 +0000

thanks! great info.
I need to implement this system. In the meantime, i had a replication error i cant figure out. Its the “duplicate entry” error, but when i checked the tables, I didnt see a duplicate!

Heres the error on the SLAVE:
Last_Error: Error ‘Duplicate entry ’555895_17327′ for key 3′ on query. Query: ‘INSERT INTO meeting_sessions (userID, meeting_id, meetingSessionID, sessionID, tstamp, action, userPosition, conport, conhost, clientID, clientVersion) VALUES (@’0′, @’1′, @’2′, @’3′, @’4′, @’5′, @’6′, @’7′, @’8′, @’9′, @’10′)’

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When I looked at the last slave record in that table, it matches the master at the same position in the table! Is there anyway to fix this without re-snapshotting the whole db?

By: timor

timor — Thu, 11 Oct 2007 11:35:39 +0000

Here id another way of checking in runtime if slave is in sync with master:

function slaveUpdated(){
[ed: snipped mangled code that checks SHOW SLAVE STATUS]