Request for Feedback: Proposal to Drop MySQL Support

[williamjallen]

CDash currently supports a choice of MySQL or Postgres for the database backend. While Laravel abstracts away many of the basic differences, it is difficult or impossible to use more complex features which differ between these two database backends while ensuring a consistent experience for end users. Kitware is considering dropping support for MySQL starting in CDash 4.0, currently scheduled for April 2025. We believe that Postgres offers better performance for typical CDash workloads, as well as a better open source ecosystem. Given that CDash uses very few MySQL-specific features, pgloader is likely sufficient for migrating most CDash databases from MySQL to Postgres.

This discussion serves as a solicitation for user feedback regarding this proposal.

[seanm]

I'd be sad to lose MySQL, as that's what I'm using currently. I've never used Postgres, so it would it yet another thing to learn (if only there were more hours in the day!)

If you do drop support, will you add some kind of database conversion script?

[seanm]

Did anyone successfully use pgloader to migrate? With which MySQL version? From what I can tell, pgloader doesn't seem to support MySQL 8.4 (current LTS) hardly at all: dimitri/pgloader#782

[williamjallen]

@seanm I'm aware of many CDash instances which have been migrated to Postgres with pgloader successfully. That said, we've found that pgloader can be tricky to get configured correctly since every MySQL instance is slightly different. If you post the specific error you're running into, it's possibly something we're already familiar with.

[seanm]

We're using MySQL 8.4, and seem to be running into this where pgloader gets nowhere fast with MYSQL-UNSUPPORTED-AUTHENTICATION.

[williamjallen]

@seanm Have you tried using the latest Docker image suggested here? We ran into a few issues which were resolved by using the latest Docker image instead of trying to build pgloader locally.

[seanm]

We haven't since 1) don't know docker 2) are on FreeBSD. But I guess it's an option. I have read that entire thread, and indeed it seems like building pgloader master may fix it. Maybe/hopefully they can make a new release soon, as that would be easier (for me). :)