Chapter 47. Logical Decoding

   Table of Contents

   47.1. Logical Decoding Examples
   47.2. Logical Decoding Concepts

        47.2.1. Logical Decoding
        47.2.2. Replication Slots
        47.2.3. Replication Slot Synchronization
        47.2.4. Output Plugins
        47.2.5. Exported Snapshots

   47.3. Streaming Replication Protocol Interface
   47.4. Logical Decoding SQL Interface
   47.5. System Catalogs Related to Logical Decoding
   47.6. Logical Decoding Output Plugins

        47.6.1. Initialization Function
        47.6.2. Capabilities
        47.6.3. Output Modes
        47.6.4. Output Plugin Callbacks
        47.6.5. Functions for Producing Output

   47.7. Logical Decoding Output Writers
   47.8. Synchronous Replication Support for Logical Decoding

        47.8.1. Overview
        47.8.2. Caveats

   47.9. Streaming of Large Transactions for Logical Decoding
   47.10. Two-phase Commit Support for Logical Decoding

   PostgreSQL provides infrastructure to stream the modifications
   performed via SQL to external consumers. This functionality can be used
   for a variety of purposes, including replication solutions and
   auditing.

   Changes are sent out in streams identified by logical replication
   slots.

   The format in which those changes are streamed is determined by the
   output plugin used. An example plugin is provided in the PostgreSQL
   distribution. Additional plugins can be written to extend the choice of
   available formats without modifying any core code. Every output plugin
   has access to each individual new row produced by INSERT and the new
   row version created by UPDATE. Availability of old row versions for
   UPDATE and DELETE depends on the configured replica identity (see
   REPLICA IDENTITY).

   Changes can be consumed either using the streaming replication protocol
   (see Section 54.4 and Section 47.3), or by calling functions via SQL
   (see Section 47.4). It is also possible to write additional methods of
   consuming the output of a replication slot without modifying core code
   (see Section 47.7).