pg_logicalinspect

pg_logicalinspect : Logical decoding components inspection

Overview

ID	Extension	Package	Version	Category	License	Language
6890	pg_logicalinspect	pg_logicalinspect	`1.0`	STAT	PostgreSQL	C

Attribute	Has Binary	Has Library	Need Load	Has DDL	Relocatable	Trusted
--s-d--	No	Yes	No	Yes	no	no

Relationships
See Also	pg_profile pg_tracing pg_show_plans pg_stat_kcache pg_stat_monitor pg_qualstats pg_store_plans pg_track_settings

Packages

PG18	PG17	PG16	PG15	PG14
1.0	N/A	N/A	N/A	N/A

This is a built-in contrib extension ship with the PostgreSQL kernel

Install

Create this extension with:

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.

Last updated on 2026-03-12

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