PGConf.Russia 2025

Currently, WAL files can be compressed with a ratio of up to 6x, but the existing compression system is inefficient.

In this talk, I’ll share my work on improving WAL compression.

Greenmask is an open-source utility for database anonymization and synthetic data generation. A common challenge in development is creating test environments that closely resemble production. In this talk, we will explore how to use Greenmask’s features to prepare a test environment with ease. 

We will discuss its architecture, database subsets, types of transformations, the reasons for integrating with the PostgreSQL driver, and porting some pg libraries. Additionally, we will explain how our technology helps businesses solve problems faster, more efficiently, and securely.

In any business-critical system, there comes a need to modify table structures — whether it's adding new columns with expressions based on other columns or converting a non-partitioned table into a partitioned one.

Using standard PostgreSQL tools for large table reorganization often results in significant downtime, as tables become unavailable for writes — and sometimes even for reads — during the process.

In this talk, I’ll introduce dbms_redefinition, a custom-built extension that brings functionality similar to Oracle’s DBMS_REDEFINITION package to PostgreSQL. This solution minimizes downtime to near zero when applying schema changes in production. 

Unlike pg_repack, which does not support structural modifications, dbms_redefinition is useful for all PostgreSQL users, even beyond Oracle migrations.

I’ll share a real-world use case, discuss future development plans, and explore new features in the pipeline.

The work of a DBA is very multifaceted: backups, version updates, performance issues — there's a long list. But sometimes, due to the workload, we don't give enough attention to innovations that don't directly relate to what we do every day. Such is the case with logical replication.

Of course, each of us has some skills working with this tool, but PostgreSQL is a rapidly evolving database system. Sometimes, we simply need to look around with a fresh perspective to see something new.

My presentation will be based on this approach: we'll start with theory (as always, less theory, more practice) and simple examples, then move on to more complex examples of its use. Special attention will be given to what has changed in modern versions of PostgreSQL.

This presentation will be helpful for those who want to get acquainted with logical replication or refresh their knowledge of this tool.