A few days ago, we faced an interesting problem on one of our
customer’s slave mysqld servers. An Alter for adding a new
column was run on master server took 542 seconds where as it took
few hours on the slave server to complete due to a SELECT
blocking the Alter was not allowed to complete.
Here is the the select on the master server and it’s execution time from the binary logs.
# at 825737566 #110720 19:55:21 server id 31415 end_log_pos 825737730 Query thread_id=83250629 exec_time=542 error_code=0 use collect/*!*/; SET TIMESTAMP=1311216921/*!*/; /*!\C latin1 *//*!*/; SET …[Read more...]