PGConf.Russia 2018

Rambler & Co is a lot of publications, services and projects. Appear new and grow existing. This environment requires a reliable, fault-tolerant, scalable, automated system.

I'll tell you about the structure of our PostgreSQL SaaS, what tools and technologies we use. Quorum of 3 Data Centers. A single entry point for clients based on dynamic routing. Emergency switching of the primary server. Transparent scaling for reading. Create a replica without load on the cluster. Transparent transfer of PostgreSQL cluster to other servers. Update dev environment from prod for development. Backup with compression and the use of multiple CPUs on the side of the database, the restoration of one database from basebackup. Monitoring of sql queries.

The speaker will share his experience of transferring high-loaded game projects that were originally developed to work with MySQL into PostgreSQL. Problems that had been expected and ones that were actually faced. Tricky bugs that were found in production servers after the migration. Solutions that were used to deal with problems. PostgreSQL features that were very useful and desirable ones that were missing.

Many of us know that it is MVCC that provides concurrency access to data in many relational databases that guarantee transactions consistency and isolation. But only deep understanding of the implementation of this mechanism in PostgreSQL allows us to better understand the processes in the database, to design the application logic and table structures to be the most effective in a high-load world. We'll take one of the processes in our product to understand how MVCC is implemented in PostgreSQL and we'll explain one of the peculiarity when seemingly unrelated activities can affect each other.

This report is about my PostgreSQL extension pg_profile. This extension all you need to create periodic statistics snapshots and to keep them. You can build a report on one or many serial snapshots. This report will contain statistics information about database workload in specified time period. It is very useful to start investigation on performance degragation or excessive resoure consumption in the past.