There are a lot of postgres fans on HN, would you mind giving some more info on why you want to go from PG to MySQL?

No explanation he could possibly give on HN will prevent him being down voted. Sad but true

I did a project with postgres and symfony+doctrine.

At 80% of completion, I moved to mySql because I needed spatial index, I installed Postgis but got a lot of problems with doctrine-migration.

There are some nice features that MySQL lacks. Personally, the thing I like best in Postgres is transactional DDL. In MySQL, if halfway through a database transformation your migration script fails, you are in a broken state and you are on your own. Postgres rolls the whole transaction back. Ofcourse there are some other features MySQL lacks, such as variable length character columns (varchar) where you don't need to specify a maximum length.

The transactional DDL seems to be introduced in MySQL per 8.0 though

The advantages of Postgres (and MariaDB) over MySQL are pretty well traveled on HN. OP wants to move from Redshift Postgres & SQL Server to MySQL - which isn't something you see very often.

> The transactional DDL seems to be introduced in MySQL per 8.0 though

I thought so as well from the release note wording, thanks to theptip for confirming in the docs that DDL is not transactional in 8.0, just crash-safe. see https://news.ycombinator.com/item?id=16876549.

You want to go from Postgres TO MySQL‽ Why do you want to do that?

Uber really just needed a key/value store. MySQL works better when used that way since PostgreSQL has MVCC and can lead to table bloat and compaction issues.

I doubt many others ever encounter this issue since picking the correct data store is step 1.

InnoDB also has MVCC. Always has. It just uses a different strategy to avoid the table bloat and compaction issues.

As far as I am aware there is no good reason to not use MariaDB instead of MySQL. The creator of MariaDB, Monty Widenius, was on a episode of the changelog podcast if you want to hear some background as to why.

Former MySQL Product Manager here (no longer affiliated).

I've been to a Monty talk about this subject, and let me say it was interesting...

Monty starts by saying that he does not acknowledge MySQL 5.6's existence since some new features are an abomination (usually citing GTIDs).

He then compares MySQL 5.5 to MariaDB (of which MariaDB is based on MySQL 5.5; so it contains the superset of features).

MySQL 5.5 was released in 2010. Support for it will end at the end of this year.

Development has diverged a lot since 2010. For a more balanced comparison, I recommend this one: https://www.percona.com/blog/2017/11/02/mysql-vs-mariadb-rea...

Monty is also the CTO of the MariaDB Corporation, which is a VC-funded entity. I would fully expect him to sing MariaDB's praises in a podcast.

Large companies have come to a different conclusion, at least so far. Among companies with very large database fleets, there's much greater usage of MySQL and Percona Server than MariaDB.

Granted, Linux distributions have leaned more towards shipping MariaDB by default instead of MySQL. This makes sense given that Oracle is, well, Oracle.

We switched to MariaDB on freebsd 2 or 3 years ago. We ran into a couple performance-destroying bugs and while the devs acknowledged the issues, they made it clear they wouldn't be fixed any time soon. MySQL has been solid for us though.

Just a personal experience.

Redshift is forked off an ancient Postgres version, consider using a more recent (10 or 11 beta) real Postgres version.

Like AWS redshift the nosql database or what? What is redshift postgres?

AWS Redshift is their data warehouse database. It uses Postgres syntax. DynamoDB is their NoSQL offering.

Redshift is a columnar SQL database, based on an old version of PostgreSQL.