---
title: "pg_logicalinspect — logical decoding components inspection"
id: pglogicalinspect
pg_version: "20devel"
---

<a id="pglogicalinspect"></a>

## F.28. pg_logicalinspect — logical decoding components inspection

The `pg_logicalinspect` module provides SQL functions that allow you to inspect the contents of logical decoding components. It allows the inspection of serialized logical snapshots of a running PostgreSQL database cluster, which is useful for debugging or educational purposes. 

By default, use of these functions is restricted to superusers and members of the `pg_read_server_files` role. Access may be granted by superusers to others using `GRANT`. 

<a id="pglogicalinspect-funcs"></a>

### F.28.1. Functions

<a id="pglogicalinspect-funcs-pg-get-logical-snapshot-meta"></a>

** `pg_get_logical_snapshot_meta(filename text) returns record` **

 Gets logical snapshot metadata about a snapshot file that is located in the server's `pg_logical/snapshots` directory. The `filename` argument represents the snapshot file name. For example: 
postgres=# SELECT * FROM pg_ls_logicalsnapdir();
-[ RECORD 1 ]+-----------------------
name         | 0-40796E18.snap
size         | 152
modification | 2024-08-14 16:36:32+00

postgres=# SELECT * FROM pg_get_logical_snapshot_meta('0-40796E18.snap');
-[ RECORD 1 ]--------
magic    | 1369563137
checksum | 1028045905
version  | 6

postgres=# SELECT ss.name, meta.* FROM pg_ls_logicalsnapdir() AS ss,
pg_get_logical_snapshot_meta(ss.name) AS meta;
-[ RECORD 1 ]-------------
name     | 0-40796E18.snap
magic    | 1369563137
checksum | 1028045905
version  | 6
  If `filename` does not match a snapshot file, the function raises an error. <a id="pglogicalinspect-funcs-pg-get-logical-snapshot-info"></a>

** `pg_get_logical_snapshot_info(filename text) returns record` **

 Gets logical snapshot information about a snapshot file that is located in the server's `pg_logical/snapshots` directory. The `filename` argument represents the snapshot file name. For example: 
postgres=# SELECT * FROM pg_ls_logicalsnapdir();
-[ RECORD 1 ]+-----------------------
name         | 0-40796E18.snap
size         | 152
modification | 2024-08-14 16:36:32+00

postgres=# SELECT * FROM pg_get_logical_snapshot_info('0-40796E18.snap');
-[ RECORD 1 ]------------+-----------
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 | 0/00000000
next_phase_at            | 0
committed_count          | 0
committed_xip            |
catchange_count          | 2
catchange_xip            | {751,752}

postgres=# SELECT ss.name, info.* FROM pg_ls_logicalsnapdir() AS ss,
pg_get_logical_snapshot_info(ss.name) AS info;
-[ RECORD 1 ]------------+----------------
name                     | 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 | 0/00000000
next_phase_at            | 0
committed_count          | 0
committed_xip            |
catchange_count          | 2
catchange_xip            | {751,752}
  If `filename` does not match a snapshot file, the function raises an error. <a id="pglogicalinspect-author"></a>

### F.28.2. Author

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>