PgConf.Russia 2019

PostgreSQL + PostGIS + TimescaleDB is a ready-to-use symbiosis from a reliable RDBMS, a powerful set of geographical objects and calculations, and work with time-series data. This bundle perfectly solves the problem of storing telemetry, while leaving the whole PostgreSQL ecosystem in your hands.

Sometimes there is a great desire to return the database to the past, for a day or two or more days. The reasons are diverse, but most often one is to see what has changed. Or to see if the application behaved incorrectly after the update. Or it was just a command from the boss. The classic way everyone knows is to keep full backups and sets of WAL-logs to be able to recover to an arbitrary moment. This method is a real headache for DBAs/administrators, and it will not work quickly. Sure, there are some ways to optimize this process, but downtime is inevitable. PostgresPro offers a new way — database snapshots and the ability to return to them.

Patroni is getting art of state standard framework for building HA clusters with postgres now.

During session we will build simple 3 node cluster using mentioned stack.

We will discuss patroni's architecture, and most interesting parameters from it's configuration. We will check how actually failover works and how could you initialise cluster.

After session you will be able to built such cluster from scratch in minutes using given ansible playbooks.

PostgreSQL provides possibility to create temporary tables. Though a temporary table is accessible only to a single session and is removed at the end of the session, all information about it is stored in the system catalogs of PostgreSQL. This is related to several issues, which make it difficult or impossible to use temporary tables in some cases. There are attempts to solve this feature, including in our company. But they have not yet succeeded, mainly because of the PostgreSQL engine. In the talk I want to tell about simple and small pg_variables extension. It allows you to create table variables along with scalar ones. I will tell how it can replace temporary tables, what advantages and disadvantages it has.