pierreforstmann / pg_log

PostgreSQL extension to display log from SQL

pg_log

PostgreSQL extension to display log from SQL

Installation

Compiling

This module can be built using the standard PGXS infrastructure. For this to work, the pg_config program must be available in your $PATH:

git clone https://github.com/pierreforstmann/pg_log.git
cd pg_log
make
make install

This extension has been validated with PostgreSQL 10, 11, 12, 13, 14, 15 and 16.

PostgreSQL setup

Extension must loaded at server level with shared_preload_libraries parameter.

shared_preload_libraries = 'pg_log'

Following SQL statement must be run in the database that will store pg_log objects:

create extension pg_log;

You must also set logging_collector to on and valid value for log_filename.

Usage

pg_log has 3 specific GUC settings:

1. pg_log.fraction which is the log fraction that is displayed between 0 and 1. To display 10% of log contents starting from the end, use pg_log.fraction=0.1. Default value is 0.01 (1%).
2. pg_log.naptime is the duration between each log refresh in the database. Default value is 30 seconds.
3. pg_log.datname is the database name where pglog table and log view are created. This database must be created before installing the extension. Default database name is pg_log.

Example

Add in postgresql.conf:

shared_preload_libraries = 'pg_log'

Create database pg_log:

create database pg_log;

Run in database pg_log:
create extension pg_log;

To display 1% of log contents connect to database pg_log and query the log view:
\c pg_log
select * from log;