PGConf.Russia 2023

Since PostgreSQL 9.5 logical replication has replication origin infrastructure for replication progress tracking. Now 16th version is coming with feature which made bi-directional replication setups possible using said infrastructure. In earliest reviews it got a nickname of "native multimaster" for cluster, interconnected with said replication, bearing some resemblance to PostgresPro's Multimaster. We're going to figure out degree of it and explain insides of them. Talk expects you to have a basic knowledge of WAL insides and it's role in PostgreSQL functioning.

The history of import substitution did not start last year after well-known events. Its launch dates back to 2014. It was from this year that state and near-state companies began to think of switching to the so called "recommended software". One of these companies approached us back in 2020 with a project to move from Oracle to PostgreSQL. This project was designed to solve the accumulated architectural problems (imperfect storage system for telemetry data, the DBMS itself worked inside a virtual machine), and optimize the use of disk space (make space in the main storage, debug saving archived data, ensure correct backup). Since the customer's system should have worked uninterrupted 24/7, it was necessary to switch from one DBMS to another "seamlessly" without downtime, with simultaneous operation of both to ensure step-by-step translation of subsystems and the ability to control the correctness of the data. And, of course, the work had to be completed as quickly as possible.

In the report we will discuss how we managed to solve this case.

In this talk I’ll show some new abilities in postgres observability. There will be Graphana visualization of pg_profile/pgpro_pwr data, manual highlighting of interesting objects in pg_profile/pgpro_pwr reports, further development of extended vacuum statistics in PostgresPro releases and a new session and query tracing technique in pgpro_stats extension

In this presentation, we cover multi-transactions, explain when they appear and how they can be monitored and checked. We also tackle the possible issue with multi-transaction ID wraparound and the problem of file absence in pg_multixact/offsets when restoring from a backup.