PGConf.Russia 2022

PostgreSQL has a number of peculiarities that you need to take into account not only while maintaining your database but also when designing your database schema. Experienced PostgreSQL are well aware of vacuuming process. On the web one can find tons of materials covering its internals, configurations and monitoring. Many valuable talks about vacuum were given at numerous conferences. However, we still face the common wraparound problem when the maximum possible number of transactions (xid) is reached. It happens even on databases that are relatively small in size. In my presentation, I will share a customer case that looks interesting to me. A chain of mistakes made at different stages of the database's life cycle once caused a disaster. The database fully stopped for one week, we detected a wraparound and spotted corrupted blocks. Maintenance was problematical, and we spent sleepless nights in search of a solution. We managed to achieve a local win as we finally restored the database, but it's not the end of this story, which makes it even more interesting.

My talk covers PostgreSQL infrastructure in Ozon: - how do we tune virtual machines (KVM); - which version control system we have created; - which drivers we make and how it relates to fault tolerance and load balancing; - how do we make "hot" upgrades for the parameters of our virtual machines.

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.