PGConf.Russia 2022

The release cycle for version 15 is nearing completion. At the time of the presentation, the complete list of changes will not be known. But for sure there will be something to talk about.

Implementation of ETL is one of the first tasks that any PostgreSQL user needs to solve. There is a misconception that low-code tools implementing ETL procedures reduce requirements for the user, but due to sacrificing performance and/or flexibility to this goal. The presentation will demonstrate that it is possible to design ETL procedures quickly and easily without losing productivity. We will explain how high speed is ensured, how PostgreSQL features are used and how the combination of PostgreSQL and low-code platforms allows you to get rid of one of the most frequent user pains.

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.

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.