Pythian Group

Here’s a sneak peek at a video matrix — this is all the videos that include Pythian Group employees at the MySQL conference. I hope to have all the rest of the videos processed and uploaded within 24 hours, with a matrix similar to the one below (but of course with many more sessions).

The Maatkit toolkit is a real blessing for the MySQL DBA. And while its documentation is pretty good, in some cases it’s necessary to read carefully a second and third time to make sure you are not missing an important piece of information. In this article I will comment on mk-table-chksum and mk-table-sync. My comments are mostly aimed at those DBAs who are considering using these utilities with medium or larger-sized databases.

–replicate

This option allows you to store the checksum results on the master, in a table that will get replicated to the slaves. Although it might seem like overhead for a simple check, it really simplifies your life, especially when used in combination with mk-table-sync. I always use it, for the following reasons:

• You only need to run mk-table-chksum on the master.
• A simple query will tell you the slave status.
• When used with --chunksize, it divides the checking and synching into manageable portions.
• It’s the best way to get consistent checks between master and slaves.

I always define the table as an InnoDB table to improve concurrency and avoid deadlocks (see the tool documentation for details). This table can be created on any database. Just make sure that it is going to be replicated. Here’s an example of the table definition (straight from the documentation) with the InnoDB specification at the end:

Read the rest of this entry . . .