Archive for August, 2010

Slony-I, My Experience – Part 1: Installation

August 26, 2010 1 comment

Slony-I is a trigger-based master to slave(s) replication system of PostgreSQL. In order to get a very brief logical operational idea of Slony the following example shows the master-slave system for replication of (large) databases. Slony-I replicates tables and sequence objects that are grouped in sets having few objects as a proper representation of their independence from its origination. The concept would mean more meaningful after its implementation in real. As the article is the first part focusing installation so a detailed description will be followed in the coming post. From a drama I hear, ‘Evil lies in the details’. So we are skipping it for the time being and will face it when time comes. Read more…

Categories: Tutorial

PostgreSQL Point-in-time Recovery (using WAL)

August 12, 2010 1 comment

PostgreSQL is an opensource and free-to-use Object-Relational Database Management System (ORBMS) and is controlled by a group of developers and development companies. PostgeSQL has three modes of backup, i.e. dump, dump all and Write Ahead Log (WAL). I would not focus here on the difference between the three, but will introduce WAL of postgresql. Write Ahead Log is a section of Postgresql where all the psql commands that have been executed are stored. Creating a copy of these logs and executing them again will restore any crashed database. This method is called Point-in-Time recovery, where WAL’s from a certain point in time are re-run to restore (crashed or lost) databases. The tutorial will walk you through the important steps for both backup and recovery of postgresql database using this method.

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Categories: Tutorial