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SecondThought
Asked: 2012-07-31 02:26:20 +0800 CST

Find mysql replications diffs patterns

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I'm using pt-table-checksum and pt-table-sync to check for differences in my replicas. when I use pt-table-sync with the -print option, I can only see the master values.

How can I show the conflicting slave values as well? I want to see if I can find a pattern of which those diffs occur by.

mysql

1 Answers

  1. Using pt-table-sync with these options

    • --print
    • --sync-to-master

    will report the SQL changes to execute on the Slave to make the Slave match the Master.

    The Master is simply connected for comparison purposes.

    The Percona Documenation on --print option says

    Print queries that will resolve differences.

    If you don’t trust pt-table-sync, or just want to see what it will do, this is a good way to be safe. These queries are valid SQL and you can run them yourself if you want to sync the tables manually.

    For emphasis : Do not execute the output of --print AND --sync-to-master on a Master. Execute it on a Slave only.

    If you are using Circular Replication, do this

    echo "SET SQL_LOG_BIN = 0;" > ChangesToSlave.sql
pt-table-sync --print --sync-to-master ... >> ChangesToSlave.sql

    then you can run ChangesToSlave.sql on a Slave.

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