pg_squeeze

pg_squeeze : A tool to remove unused space from a relation.

Overview

Packages

Source

Install

Make sure PGDG repo available:

pig repo add pgdg -u    # add pgdg repo and update cache

Install this extension with pig:

pig install pg_squeeze;		# install via package name, for the active PG version

pig install pg_squeeze -v 18;   # install for PG 18
pig install pg_squeeze -v 17;   # install for PG 17
pig install pg_squeeze -v 16;   # install for PG 16
pig install pg_squeeze -v 15;   # install for PG 15
pig install pg_squeeze -v 14;   # install for PG 14

Config this extension to shared_preload_libraries:

shared_preload_libraries = 'pg_squeeze';

Create this extension with:

CREATE EXTENSION pg_squeeze;

Usage

pg_squeeze: A tool to remove unused space from a relation.

pg_squeeze requires wal_level = logical and must be added to shared_preload_libraries. It removes bloat from tables while allowing concurrent reads and writes, using logical decoding instead of triggers.

Register a Table for Scheduled Processing

Insert into squeeze.tables to enable periodic bloat checks:

INSERT INTO squeeze.tables (tabschema, tabname, schedule)
VALUES ('public', 'foo', ('{30}', '{22}', NULL, NULL, '{3, 5}'));

The schedule field uses a crontab-like format: (minutes, hours, days_of_month, months, days_of_week). The above checks table foo every Wednesday and Friday at 22:30.

Optional columns: free_space_extra (min % extra free space to trigger, default 50), min_size (min MB, default 8), vacuum_max_age (max time since last VACUUM, default 1h), max_retry (retry count, default 0), clustering_index (sort tuples by this index), rel_tablespace, ind_tablespaces, skip_analyze.

Ad-hoc Squeeze

SELECT squeeze.squeeze_table('public', 'pgbench_accounts');
SELECT squeeze.squeeze_table('public', 'mytable', 'my_cluster_idx', 'target_tablespace');

Start / Stop Workers

SELECT squeeze.start_worker();   -- start scheduler + squeeze workers
SELECT squeeze.stop_worker();    -- stop all workers for current database

Auto-start on cluster boot via postgresql.conf:

squeeze.worker_autostart = 'my_database your_database'
squeeze.worker_role = postgres

Monitoring

• squeeze.log – one entry per successfully squeezed table (with started, finished, ins_initial, ins, upd, del)
• squeeze.errors – errors during squeezing
• squeeze.get_active_workers() – shows currently active squeeze workers and their progress

Configuration

• squeeze.max_xlock_time – max exclusive lock time in ms (default unlimited)
• squeeze.workers_per_database – number of concurrent squeeze workers (default 1)