[Feature] Replace mysql with postgres

[albusshirazi]

Since Devlake now fully supports Postgres, lt is time to switch the default database image in the official helm chart from mysql into postgres!

[klesh]

Could you please elaborate on why we should switch to using PostgreSQL by default? Thank you!

[albusshirazi]

Yes, of course!
https://levelup.gitconnected.com/mysql-vs-postgresql-what-we-learned-after-switching-and-why-were-never-going-back-6079a752e7d0
In addition, Devlake is an analytics tool, and postgres is better in complex analytics then mysql - https://charleswan111.medium.com/mysql-vs-postgresql-a-comprehensive-comparison-of-features-and-use-cases-392d840aa20b
Moreover, mysql isn't good at heavy concurrent data write, and for Devlake it is important since there could be many different pipeline working at the same time.

[oliverpark999]

I would like to use a cloud external PostgreSQL database instead of MySQL, but I don't see it supported in the current chart. Is it not available for use yet?

[klesh]

Most of our tasks were written in a delete-and-insert manner, which caused the sizes of PostgreSQL tables to grow rapidly. I believe it would be better to default to MySQL.

[albusshirazi]

OK, sounds weird.

1. consultation with a DBA might help to improve working with the DB, no matter which type, because I am pretty sure there is a better way then delete-and-insert manner.
2. Is it possible to be allowed to change the default DB, and the grafana dashboards will still work? (Because there will be 2 options of the DB querying, and the right one will be deployed based on the configuration)

[klesh]

1. I'm not entirely sure what you mean by "changing the default DB." However, we do not change the default database from MySQL to PostgreSQL. Users can, of course, switch their database to PostgreSQL if they choose to do so.
2. No, it is not really possible due to the dialect; it requires two sets of dashboards.

I hope this clarifies things.