table_version

Overview

Version

Build

You can build the DEB packages for table_version using pig build:

pig build pkg table_version         # build DEB packages

Install

You can install table_version 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:

• Install
• pig
• dnf
• apt

pig install table_version;          # Install for current active PG version

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

dnf install -y table_version_18       # PG 18
dnf install -y table_version_17       # PG 17
dnf install -y table_version_16       # PG 16
dnf install -y table_version_15       # PG 15
dnf install -y table_version_14       # PG 14

apt install -y postgresql-18-table-version   # PG 18
apt install -y postgresql-17-table-version   # PG 17
apt install -y postgresql-16-table-version   # PG 16
apt install -y postgresql-15-table-version   # PG 15
apt install -y postgresql-14-table-version   # PG 14

Create Extension:

CREATE EXTENSION table_version CASCADE;  -- requires: plpgsql

Usage

table_version: PostgreSQL table versioning extension

PostgreSQL table versioning extension, recording row modifications and its history. The extension provides APIs for accessing snapshots of a table at certain revisions and the difference generated between any two given revisions. It uses a PL/PgSQL trigger based system to record and provide access to row revisions.

Quick Start

CREATE EXTENSION table_version;

CREATE SCHEMA foo;
SET search_path TO foo, public;

CREATE TABLE foo.bar (
    id INTEGER NOT NULL PRIMARY KEY,
    baz TEXT
);

-- Enable versioning
SELECT table_version.ver_enable_versioning('foo', 'bar');

-- Create a revision and insert data
SELECT table_version.ver_create_revision('Insert data');
INSERT INTO foo.bar (id, baz) VALUES
  (1, 'foo bar 1'),
  (2, 'foo bar 2'),
  (3, 'foo bar 3');
SELECT table_version.ver_complete_revision();

-- Show differences between revisions
SELECT * FROM table_version.ver_get_foo_bar_diff(1001, 1002);

How It Works

When a table is versioned, the original table data is left untouched and a new revision table is created with all the same fields plus _revision_created and _revision_expired fields. A row-level trigger is set up on the original table to record every insert, update and delete in the revision data table. A statement-level trigger is set up to forbid TRUNCATE.

Table Prerequisites

• The table must have a unique non-composite integer, bigint, text or varchar column
• The table must not be temporary

Auto Revisions

If you don’t want to call ver_create_revision and ver_complete_revision explicitly, auto-revision mode groups edits by transactions:

SELECT table_version.ver_enable_versioning('foo', 'bar');

BEGIN;
INSERT INTO foo.bar (id, baz) VALUES (1, 'foo bar 1');
INSERT INTO foo.bar (id, baz) VALUES (2, 'foo bar 2');
COMMIT;

BEGIN;
UPDATE foo.bar SET baz = 'foo bar 1 edit' WHERE id = 1;
COMMIT;

SELECT * FROM table_version.foo_bar_revision;

The revision message will be automatically created based on the transaction ID.

Replicate Data Using Table Differences

To maintain a copy of table data on a remote system:

-- 1. Determine which tables are versioned
SELECT * FROM table_version.ver_get_versioned_tables();

-- 2. Get the base revision
SELECT table_version.ver_get_table_base_revision('foo', 'bar');

-- 3. Create a base snapshot
CREATE TABLE foo_bar_copy AS
SELECT * FROM table_version.ver_get_foo_bar_revision(
    table_version.ver_get_table_base_revision('foo', 'bar')
);

-- 4. Get differences to apply incremental updates
SELECT * FROM table_version.ver_get_foo_bar_diff(
    my_last_revision,
    table_version.ver_get_table_last_revision('foo', 'bar')
);

Security Model

• Anyone can create revisions
• Revisions can only be completed by their creators
• Only those who have ownership privileges on a table can enable/disable versioning
• Only empty revisions can be deleted
• Only the creator of a revision can delete it

Note: Disabling versioning on a table results in all history for that table being deleted.

Key Functions