pg-replica-auditor 0.1.2

Run a few sanity checks on your logical PostgreSQL replica to make sure its the same as the primary.

pg-replica-auditor

Features

Assumptions

These tests assume that id and updated_at columns exist and have indexes for efficient querying and that the table exists on both databases.

Row comparison

Runs row comparisons between primary and replica using two methods:

1. select 8128 rows (or number of rows given to --rows) at random between MIN(id) and MAX(id)
2. select all rows between MAX(id) and MAX(id) - 1000.

Replica lag

Checks for "replica lag" by comparing MAX(updated_at) on the given table on both databases.

Requirements

1. Python 3
2. Postgres development files (required by psycopg2). On Mac OS, use brew install postgresql. On Ubuntu, install libpq-dev.

Installation

Development

Using virtualenv, pip install -r requirements.txt

Production

Using Pypi, pip install pgreplicaauditor.

Usage

This script requires three arguments:

1. --primary, any acceptable Postgres connection string (incl. DSN),
2. --replica, same as --primary but for the replica database,
3. --table, the table to check.

Optionally, if you want to see which queries it runs, you can set the --debug option. If you want to change the size of the random sample for the row comparison test, you can pass --rows=<any number here>.

Example:

$ pgreplicaauditor --primary=postgres://primary-db.amazonaws.com:5432/my_db --replica=postgres://replica-db.amazonaws.com:5432/my_db --table=immutable_items