I need to change the the length of a column in a MySQL innodb table with 164M rows. Here's the script I want to run: ALTER TABLE SESSION_DECISION CHANGE COLUMN NAME NAME VARCHAR(255);
When I tried running the alter query, the database churned for an hour and didn't complete the task. Users accessing the system (who needed to write to the table) were locked out. This is a live system so I ended up ctrl-c'ing the request to let users access the site.
(this was in the middle of the night-- usage was minimal but I was getting nervous).
I'm on MySQL 5.0.77.
Any suggestions as to how I can change the column with a minimum of downtime?