PGConf.Russia 2022

This presentation is about NULLs implementation in the Postgres database: - What is NULL? - How is it handled by various Postgres functions? - How are NULLs stored in the database? - Indexing of NULLs

Mamonsu is an active monitoring agent for PostgresSQL based on Zabbix. We are actively developing the agent: there are new unique metrics and visualization capabilities. But in addition to metrics collecting mechanism, Mamonsu has other useful features. I am going to briefly describe these features also known as "Mamonsu tools", the agent's advantages and the installation process.

Previously, we have explained the internals of Avito, discussed, where and how we store your classifieds, and how they appear on the search results. In the recent 3-4 a lot has changed in Avito. We got rid of logical replication, stopped using standby servers for reads, removed nearly all stored procedures and our custom failover solution, migrated all our classifieds into a sharded DBMS, switched from the monolith app to microservices. I'll explain why we made such decisions, list some of the problems we encountered and describe the current state of our development process.

Tasks for migrations from the classic commercial DBMSs to open-source solutions are still relevant nowadays. Tools used to migrate Oracle applications to PostgreSQL has already proved to be efficient. But what if you have SQL Server? We want to introduce you to Babelfish, a OSS solution based on PostgreSQL 13. Babelfish supports TDS network protocol, T-SQL language, and SQL extensions specific to SQL Server. However, it isn't that simple. In our talk, we'll cover the features ensuring compatibility with SQL Server, existing problems and ways to solve them. Bonus: we'll also share the story on how we added the Babelfish support in DBeaver using the JDBC driver from Microsoft.