SysAdmin Valley » mysql

Search and Replace in MySQL

mshields — Tue, 18 May 2010 12:59:51 +0000

I do a lot of work with MySQL and I’ve had this reoccuring problem were I need to find some text in a table and replace it with new text. Like say I have a table of data that talks about dogs and I want to replace every occurrence of dog with cat. The old way I would search the entire table to find all rows that have the word dog in it, then that would give me a list to manually update each row. I’d then rerun the query to see if I missed any.

Recently I found that MySQL supports a command called what else but “replace”. So let’s say I have a table called “news” and in the table is a column called “content” and I wanted to replace all references of “dog” with “cat”, here is an example query.

update news set content = replace(content, “dog”, “cat”);

Very simple, it tells MySQL to replace the “content” field with what’s in the “content” field but replace “dog” with “cat”.

Some interesting MySQL projects to check out

mshields — Thu, 11 Feb 2010 17:49:04 +0000

While working on some MySQL stuff today I came across some interesting projects. About 2 years ago I attended the Boston MySQL Meetup group which had a guest speaker (Patrick Galbraith) and he spoke about setting up MySQL in a Multi-Master setup. This is where you have two MySQL database servers and each one is a slave of the other. Today I came across two projects that look promising, the first is Multi-Master Replication Manager for MySQL (or MMM) and the second is Flipper.

MMM is a set of scripts that perform monitoring/failover and management of MySQL master-master replication. Flipper is also a set of tools that manage which server in a Multi-Master setup is writable and which is readable by moving IP addresses based on the server’s role. Both look very promising and hopefully soon I’ll have some free time to play around with them.

Working with Percona’s MySQL and RPM dependency problems

mshields — Thu, 11 Feb 2010 15:56:05 +0000

I’ve started using Percona’s version of MySQL 5.1 and have run into a few issues trying to get other tools such as mytop or maatkit to install but have been having problems with RPM dependency’s. I found the solution on this guy’s blog. Basically, if you install the MySQL-client-percona, MySQL-percona, MySQL-server-percona, MySQL-shared-percona and Percona-XtraDB, instead of installing MySQL-shared-percona, you should download and force upgrade (rpm -Uvh –force packagename) the MySQL-shared-compat library directly from MySQL. Just make sure you get the same version from MySQL that you’re using of the Percona MySQL.