Howto Backup PostgreSQL Databases Server With pg_dump command

Generally, I like to work with MySQL but some time my work force me to work with PostgreSQL database server.

Recently I had received a request to backup PostgreSQL databases as one of our client want to format and reinstall RHEL server.

PostgreSQL is a one of the robust, open source database server. Like MySQL database server, it provides utilities for creating a backup.

Step # 1: Login as a pgsql user

Type the following command:
$ su - pgsql
Get list of database(s) to backup:
$ psql -l

Step # 2: Make a backup using pg_dump

Backup database using pg_dump command. pg_dump is a utility for backing up a PostgreSQL database. It dumps only one database at a time. General syntax:
pg_dump databasename > outputfile

Task: dump a payroll database

Type the following command
$ pg_dump payroll > payroll.dump.outTo restore a payroll database:
$ psql -d payroll -f payroll.dump.outOR$ createdb payroll
$ psql payroll However, in real life you need to compress database:$ pg_dump payroll | gzip -c > payroll.dump.out.gzTo restore database use the following command:$ gunzip payroll.dump.out.gz
$ psql -d payroll -f payroll.dump.outHere is a shell script for same task:

#!/bin/bash
DIR=/backup/psql
[ ! $DIR ] && mkdir -p $DIR || :
LIST=$(psql -l | awk '{ print $1}' | grep -vE '^-|^List|^Name|template[0|1]')
for d in $LIST
do
  pg_dump $d | gzip -c >  $DIR/$d.out.gz
done

Another option is use to pg_dumpall command. As a name suggest it dumps (backs up) each database, and preserves cluster-wide data such as users and groups. You can use it as follows:$ pg_dumpall > all.dbs.outOR$ pg_dumpall | gzip -c > all.dbs.out.gzTo restore backup use the following command:
$ psql -f all.dbs.out postgresReferences:

• PostgreSQL documentation : Backup and Restore chapter