PGConf.Russia 2022

About 7 years ago, I moved from Windows-only development lead by an irresistible desire to add some parts to PostgreSQL. In this talk, I would like to cover things that were not obvious to me when I started working with the source code, the PG build and testing system. I'm going to talk about the simplest issues - routine IDE tasks, navigation, build and release process, and similar stuff. What I will share isn't the one and only truth. Some topics might relate to dummy-level problems :) I would be glad if other developers also shared the secrets of their development life. We can arrange a discussion of grep vs IDE :)

Logical decoding and replication slots introduced in PostgreSQL 9.4 (released in 2014) created a solid foundation for implementing built-in core logical replication in version 10 (released in 2017). Unfortunately, there are a few limitations that make logical replication not very useful in real-world scenarios. Logical decoding currently isn’t supported on the standby server, and PostgreSQL allows creating logical replication slots only on the primary server. Or in other words, logical slots are lost on failover/switchover.

Postgres hackers made many attempts to address the problem, and most of them resulted in not too much success. Although, there is one little function introduced in PostgreSQL 11 that made it possible to implement failover of logical replication slots externally.

In my talk I will tell a story of how Patroni solves the problem of logical replication slots failover without using invasive third-party extensions, dig down into some of the Postgres internals in order to prove why this approach is safe, and finally, we will discuss limitations and potential downsides of this solution.

I am going to explain a sorting method added in Postgres 14 that allows to create GiST index much faster. We'll also talk about the disadvantages of this sorting method discovered during implementation of its support in PostGIS and how it will be improved in the future. Also, new features and improvements included in PostGIS 3.2 will be reviewed.

SPQR is a lightweight OLTP sharding solution written in Go. In this talk, I'm going to discuss design decisions that led us through FDW-based sharding, CustomNode-based sharding, C-implemented lightweight query routing, and finally to SPQR design.