PGConf.Russia 2021

The pgpro_scheduler extension has an interesting but little-known feature - one-time jobs. Despite its simplicity, this feature can be used for complex transaction processing. On the one hand, it helps to reliably execute tasks taking a very long time, on the other hand, it ensures app scaling if certain conditions are met.

Everyone knows very well what a failover cluster PostgreSQL is and how such a cluster protects against failures within the same data center. However, recently, more and more enterprises have placed increased demands on their services, these requirements include disaster tolerance. We call such clusters a GEO-Cluster (KUK). In the report, I will talk about the varieties, principles and approaches to building GEO-Clusters PostgreSQL based on the Corosync/Pacemaker cluster software.

We'll discuss our approaches to picking technical solutions for the systems we design. We'll consider their advantages and limitations. We'll share the facts about the changes in our engineering culture when import substitution requirements came into effect. We migrated the system with a classical three-tier architecture from Oracle to Postgres Pro DBMS. In my presentation I'll pay attention to data migration tools and peculiarities of development Java/Kotlin apps and SQL interoperability between two DBMSs.

In OZON, we work on PostgreSQL as a service. Currently, we have thousands of clusters. We know about the important questions software developers ask, and the most crucial ones are as follows: how to understand the database's workload and why this query is getting slow? In this presentation, I will explain how we help our developers answer these questions by simply having a look at our dashboard.