PGConf.Russia 2025

The issue of slow month-end closing and cost calculation on PostgreSQL has been a long-standing problem. In this talk, we will explore what modern versions of PostgreSQL offer in this regard and answer the question, "Do replicas slow down the master?"

We will also take a look at different types of physical replication and, for dessert, share a recipe for quick and painless month-end closing in 1C without affecting the daily operations of users.

The execution time of SQL queries depends on factors like indexes and up-to-date statistics. In most cases, optimizing slow queries helps resolve database performance issues.

But what if classic query optimization doesn’t work? What if the system keeps behaving unpredictably — or worse, crashes, leading to frustration, panic, and even despair?

In this talk, we’ll explore how Postgres Professional’s performance engineers tackle these challenges, look at the tools they use, what’s still missing, and where PostgreSQL performance optimization is headed

This talk explores the challenges we encountered — and solved — while migrating massive databases from Oracle to PostgreSQL.

One of the most complex aspects of this process was rebuilding foreign keys (FKs). To overcome these challenges, we had to dive deep into the internal workings of FK creation and validation.

Key topics include:

Does ALTER TABLE ... ADD CONSTRAINT ... FOREIGN KEY have an execution plan?

Can an ordinary user influence this process?

What locks are applied during FK creation and validation?

Also, we’ll introduce a first-principles method for investigating performance issues, applying it to a real-world FK creation bottleneck.

In some cases, business logic is implemented directly within the database. It's well known that maintaining and developing business logic becomes much easier when it's covered by tests. However, backend tests often treat the database as an external resource and don’t always interact with a live database.

This talk will introduce an enhanced version of the pgTap library, designed not only to facilitate unit testing and CI for database code but also to accelerate the development process itself.