I have 2 slaves where one is working as expected, but the other slave is extremely slow when executing update statements. The insert and delete statements are fast.

I used the command check table tbl_name to see if any MyISAM table was corrupt. Both the slaves are MyISAM only.

I am using (AWS ec2 instance) ext3 for the fast slave and xfs for the the other. Is that the reason why the updates are taking time?

  • You are at the mercy of what AWS thinks is a good config for your part of a computer. Post more details; maybe there is something that can be fixed.
    – Rick James
    Commented May 29, 2012 at 21:24

1 Answer 1


You can compare both slaves performance using Percona utilities mentioned below:

  • pt-heartbeat measures replication lag on a MySQL server. You can use it to update a master or monitor a replica. If possible, MySQL connection options are read from your .my.cnf file.
  • pt-table-checksum performs an online replication consistency check by executing checksum queries on the master, which produces different results on replicas that are inconsistent with the master.

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