Repartitioning with logical replication in PostgreSQL 13

So, you have a partitioned table. And you want to change your mind. Re-partitioning is "easy" if you can take downtime -- just create a new table with a new name and copy all the data over. But what if we want to try to do it without downtime? Logical replication enhancements in PostgreSQL 13 brings us some new options for this!

But first a disclaimer -- this is definitely not pretty! And does not take into consideration things like foreign keys and similar. But sometimes a quick hack can be the best hack.

So let's go!

Continue reading

Another couple of steps on my backup crusade

For a while now, I've been annoyed with how difficult it is to set up good backups in PostgreSQL. The difficulty of doing this "right" has pushed people to use things like pg_dump for backups, which is not really a great option once your database reaches any non-toy size. And when visiting customers over the years I've seen a large number of home-written scripts to do PITR backups, most of them broken, and most of that breakage because the APIs provided were too difficult to use.

Over some time, I've worked on a number of ways to improve this situation, alone or with others. The bigger steps are:

• 9.1 introduced pg_basebackup, making it easier to take base backups using the replication protocol
• 9.2 introduced transaction log streaming to pg_basebackup
• 9.6 introduced a new version of the pg_start_backup/pg_stop_backup APIs that are needed to do more advanced base backups, in particular using third party backup tools.

For 10.0, there are a couple of new things that have been done in the past couple of weeks:

Continue reading