PgConf.Russia 2016

The talk describes performance benchmarking results of PostgreSQL on modern Hi-End servers. The main attention was paid to the locks for shared data access and associated bottlenecks. The testing propose was to test the linear read scalability limits with an increase of cores number allocated for PostgreSQL. Testing was performed for different postgres versions (9.4, 9.5, 9.6) to check new features designed to increase performance on multiprocessing architectures.

We love to stress test software, since we are a performance engineering company. Our friends from a hosting company servers.com provided us with a modern dedicated server so we immediately started to test PostgreSQL in different environments, including SmartOS, DragonFly and Windows. We would like to present our results (and all the gory details) to community.

Postgres 9.5 adds many features designed to enhance the productivity of developers: UPSERT, CUBE, ROLLUP, JSONB functions, and PostGIS improvements. For administrators, it has row-level security, a new index type, and performance enhancements for large servers. This talk covers the top ten new features that appeared in the Postgres 9.5 release. It will also cover some of the major focuses for post-9.5 releases.

Postgresql's buffer manager has parts where it's showing its age. We'll discuss how it currently works, what problems there are, and what attempts are in progress to rectify its weaknesses.

• Lookups in the buffer cache are expensive
• The buffer mapping table is organized as a hash table, which makes efficient implementations of prefetching, write coalescing, dropping of cache contents hard
• Relation extension scales badly
• Cache replacement is inefficient
• Cache replacement replaces the wrong buffers