PostgreSQL 15 Released: The MERGE Command and Faster Sorting

What happened

PostgreSQL 15 was released on October 13, 2022, according to the PostgreSQL Global Development Group. The release built on recent performance gains and added a long-requested SQL-standard command, along with improvements to replication, logging and configuration.

The MERGE command

PostgreSQL 15 introduced the SQL-standard MERGE command, which lets developers write conditional statements that combine INSERT, UPDATE and DELETE actions in a single statement based on whether rows match. MERGE had long been available in other databases and was a frequently requested feature, simplifying common upsert-style logic. The release also added regular-expression functions such as regexp_count(), regexp_instr(), regexp_like() and regexp_substr().

Faster sorting and compression

The release improved PostgreSQL's in-memory and on-disk sorting algorithms, with benchmarks showing speedups of 25% to 400% depending on the data types sorted, and allowed SELECT DISTINCT queries to run in parallel. It added LZ4 and Zstandard compression for write-ahead log files, offering space and performance benefits, and server-side compression options for the pg_basebackup backup tool.

Replication, logging and security

PostgreSQL 15 gave logical replication more flexibility with row filtering and column lists, letting users replicate a subset of a table, plus better conflict management. It introduced a new jsonlog logging format for structured logging systems, let administrators grant permission to alter server-level configuration, and, as a security hardening step, revoked the CREATE permission on the public schema from users other than the database owner.

Why it mattered

PostgreSQL 15's MERGE command closed a notable gap with the SQL standard and other databases, while the sizeable sort-performance improvements and WAL compression benefited real workloads. The public-schema permission change was a meaningful security default that reduced the risk of accidental object creation in shared databases.

Related on Skillo

See also: PostgreSQL 16's logical replication from standbys.

Sources

• PostgreSQL 15 Released! (official announcement)

Published date reflects the original event date (2022-10-13). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.