pg_logicalinspect

Logical decoding components inspection

https://www.postgresql.org/docs/devel/pglogicalinspect.html

Overview

Package	Version	Category	License	Language
`pg_logicalinspect`	`1.0`	STAT	PostgreSQL	C

ID	Extension	Bin	Lib	Load	Create	Trust	Reloc	Schema
6890	`pg_logicalinspect`	No	Yes	No	Yes	No	No	-

Related	`wal2json` `pgoutput` `test_decoding` `pg_walinspect` `decoderbufs` `wal2mongo` `decoder_raw` `pgmqtt` `kafka_fdw` `pgq`

Version

PG18	PG17	PG16	PG15	PG14
1.0	✗	✗	✗	✗

Install

Note: This is a built-in contrib extension of PostgreSQL

CREATE EXTENSION pg_logicalinspect;

Usage

pg_logicalinspect: inspect logical decoding snapshot files

pg_logicalinspect provides SQL functions to examine serialized logical decoding snapshots stored in pg_logical/snapshots/, useful for debugging and educational purposes.

Functions

pg_get_logical_snapshot_meta(filename text) – snapshot file metadata:

SELECT * FROM pg_get_logical_snapshot_meta('0-40796E18.snap');

 magic      | 1369563137
 checksum   | 1028045905
 version    | 6

pg_get_logical_snapshot_info(filename text) – detailed snapshot information:

SELECT * FROM pg_get_logical_snapshot_info('0-40796E18.snap');

 state                    | consistent
 xmin                     | 751
 xmax                     | 751
 start_decoding_at        | 0/40796AF8
 two_phase_at             | 0/40796AF8
 initial_xmin_horizon     | 0
 building_full_snapshot   | f
 in_slot_creation         | f
 last_serialized_snapshot | 0/0
 committed_count          | 0
 committed_xip            |
 catchange_count          | 2
 catchange_xip            | {751,752}

Listing Available Snapshots

Combine with pg_ls_logicalsnapdir() to discover and inspect all snapshots:

SELECT ss.name, meta.*
FROM pg_ls_logicalsnapdir() AS ss,
     pg_get_logical_snapshot_meta(ss.name) AS meta;

SELECT ss.name, info.*
FROM pg_ls_logicalsnapdir() AS ss,
     pg_get_logical_snapshot_info(ss.name) AS info;

Access Control

Restricted to superusers and members of pg_read_server_files by default.