Presented by:

Nishchay Kothari

Fujitsu Australia Limited
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Logical replication plays an important role in PostgreSQL for zero-downtime migrations, selective data replication, platform modernisation, and data integration. Traditionally, enabling logical decoding required setting wal_level = logical and restarting PostgreSQL. In production environments, this could introduce unnecessary downtime or force organisations to keep wal_level permanently set to logical, even when logical replication was not actively required.

PostgreSQL 19 introduces dynamic WAL level adjustment, removing this long standing operational limitation.

With wal_level = replica, PostgreSQL can now automatically raise the effective WAL level to logical when a logical replication slot is created, without requiring a database restart. When logical replication is no longer needed and the logical slots are removed or invalidated, PostgreSQL can transition the effective WAL level back to replica. A new read-only parameter, effective_wal_level, provides visibility into the WAL level currently being used by the server.

In this webinar, we will explore how dynamic WAL level works and what happens behind the scenes when PostgreSQL transitions between replica and logical. We will look at logical replication slot lifecycle management, asynchronous WAL-level demotion, the role of the checkpointer, and how these changes affect WAL generation and operational management.

We will also examine the behaviour in primary-standby architectures, including how WAL level changes propagate to standby servers and what this means for logical replication slots created on standbys.

Through practical demonstrations and real-world scenarios, attendees will learn how PostgreSQL 19 simplifies logical replication, reduces restart-driven operational workflows, and enables logical decoding to be activated only when it is actually required.

Date:
Duration:
50 min
Room:
Conference:
PostgresWorld Webinars: 2026
Language:
Track:
Ops
Difficulty:
Easy
Requires Registration:
Yes (Registered: 0)