Monday, October 12, 2015

Do not run those commands with MariaDB GTIDs - part # 1

In the spirit of sharing war stories and avoiding others to do the same mistakes as I did, here are some sequences of commands that you should avoid to run on a MariaDB slave that is lagging and which is using the GTID protocol.  Remember, do not run those because...

So, those bad commands are the following:
  • or "STOP SLAVE; START SLAVE;" (to remove an UNTIL condition as an example),
  • or "STOP SLAVE; SET GLOBAL slave_parallel_threads=...; START SLAVE;",
  • and maybe others.
Can you guess why those commands are bad (or other sequence of commands that would be bad in the same way) ?  If yes, post a comment.  I will give more details in part # 2, including better options.

Note: MySQL also has similar problems, I have just not been bitten by them recently, more in part # 2.

1 comment:

  1. Nothing comes to my mind. I am very keen so see what is in your post #2 :)