MySQL 4.1 to 5.1 large scale upgrade

[Randeep Mann]

Hi Guys,
Performing MySQL upgrade two things should normally worry you. It is Regressions – functionality regressions when what you’ve been using before does not work any more or works with different result and performance regressions when performance (in a broad sense) is negatively affected.

In general even minor MySQL version upgrade can have both of these issues. It gets larger as you have a larger leap in minor version – Upgrade of MySQL 5.0.30 to 5.0.32 is generally likely to expose less issues than 5.0.30 to 5.0.86. The largest amount of potential issues happens when you upgrade to different major version, especially if you skip over one. MySQL 5.0 to 5.1 upgrade is a lot safer upgrade path than 4.1 to 5.1 just because so much more people have followed that road.