pg_relusage

Overview

LOAD/preload enables logging; CREATE EXTENSION only records installation.

Version

Build

You can build the RPM / DEB packages for pg_relusage using pig build:

pig build pkg pg_relusage         # build RPM / DEB packages

Install

You can install pg_relusage directly. First, make sure the PGDG and PIGSTY repositories are added and enabled:

pig repo add pgsql -u          # Add repo and update cache

Install the extension using pig or apt/yum/dnf:

pig install pg_relusage;          # Install for current active PG version

pig ext install -y pg_relusage -v 18  # PG 18
pig ext install -y pg_relusage -v 17  # PG 17
pig ext install -y pg_relusage -v 16  # PG 16
pig ext install -y pg_relusage -v 15  # PG 15
pig ext install -y pg_relusage -v 14  # PG 14

dnf install -y pg_relusage_18       # PG 18
dnf install -y pg_relusage_17       # PG 17
dnf install -y pg_relusage_16       # PG 16
dnf install -y pg_relusage_15       # PG 15
dnf install -y pg_relusage_14       # PG 14

apt install -y postgresql-18-pg-relusage   # PG 18
apt install -y postgresql-17-pg-relusage   # PG 17
apt install -y postgresql-16-pg-relusage   # PG 16
apt install -y postgresql-15-pg-relusage   # PG 15
apt install -y postgresql-14-pg-relusage   # PG 14

Preload:

shared_preload_libraries = 'pg_relusage';

Usage

Sources:

• README.md
• Control file
• Implementation

pg_relusage 1.0.2 logs relations used by statements after plan simplification. It supports PostgreSQL 10–18 and defines no SQL objects. Loading the library enables it; optional CREATE EXTENSION only records installation.

Core Workflow

LOAD 'pg_relusage';
SET pg_relusage.nested_statements = 'fold';
SET pg_relusage.log_level = 'notice';
CREATE TABLE relusage_demo (id integer);
SELECT * FROM relusage_demo;

Operational Boundaries

All settings require superuser: pg_relusage.enabled defaults on, pg_relusage.log_level defaults log and pg_relusage.rel_kinds defaults riSvmfp. pg_relusage.nested_statements accepts all (default: each statement), top (ignore nested statements) or fold (merge nested relations into the outer log). Version 1.0.1 fixes fold handling after a failed subtransaction.

Use session_preload_libraries for new sessions without a restart, or shared_preload_libraries for all sessions with a restart; preserve existing preload entries. LOAD normally requires superuser. Log messages omit SQL text, so configure log_line_prefix to identify the client.

System catalogs are excluded. Relations eliminated by planning or startup pruning are excluded, but partitions skipped later during execution can still appear. INSERT into a partitioned table reports only its parent. Deferred triggers at COMMIT, COPY FROM triggers and planner-invoked functions are treated as top-level statements. DDL and maintenance commands are excluded. A quiet log alone does not prove an object can be dropped.

1.0.2 and Partitioned Tables

Version 1.0.2 reduces relation-membership and partition-matching overhead for statements involving many partitions. Log format and settings are unchanged. Replace the library and restart if using shared preload, or reconnect when using session preload or LOAD. If installation was recorded with CREATE EXTENSION, also run ALTER EXTENSION pg_relusage UPDATE.