Howto Backup PostgreSQL Databases Server With pg_dump command

last updated in Categories Backup, Data recovery, Howto, Linux, Postgresql, UNIX

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:

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Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

29 comment

  1. sir,
    i am not able to take the backup of postgresql database.in pg_dump commnad it provide me “access denied ”
    thanks

  3. Man, please remember that if you use the gzip option with pg_dumpall you HAVE TO use the gunzip to restore the backup.

    gunzip all.dbs.out.gz

    and then

    psql -f all.dbs.out postgres

  4. The script has a little bug. On,
    LIST=$(psql -l | awk ‘{ print $1}’ | grep -vE ‘^-|^List|^Name|template[0|1]’)

    if you have a list with several databases, the last row is number. For example in my case:
    (19 rows)
    and after the script
    (19

    so I propose you generate the LIST with this:
    LIST=$(psql -l | awk ‘{ print $1}’ | grep -vE ‘^-|^List|^Name|template[0|1]|^(‘)

    Otherwise, it’s a very nice article.

    Thanks.

  5. Thanks Vivek for the great script.

    Just a few notes:

    In the 3rd line
    [ ! $DIR ] && mkdir -p $DIR || :
    there should be no space character after the exclamation mark!
    [ !$DIR ] && mkdir -p $DIR || :
    like this it works for me.

    @Leopold, thanks for your comment, I had the same problem and your expression for LIST was the solution 🙂

  6. i have taken backup of DB from other machine. so i want the run those DB on my box.

    what are the steps i need to follow to achive it.

    please help me

  7. Needed help,new person in software using POSTGRE SQL please guide me with commands that will help to take backup easily and similarly restore when needed.

  8. Nice tip, thanks. I have a few notes to share.

    You can also avoid the number of rows returned with the “-t” option to psql:

    psql -lt

    Also, to run the script as root from cron, I used su to run the backup as the postgres user. My complete script:

    #!/bin/sh
DIR=/backup/pgsql

LIST=$(su - postgres -c "psql -lt" |awk '{ print $1}' |grep -vE '^-|^List|^Name|template[0|1]')

for d in $LIST
do
  su - postgres -c "/usr/bin/pg_dump $d | gzip -c > $DIR/$d.sql.gz"
done

  9. Hi
    I want take backup from Postgresql in Tehran (city in Iran) and store it in Sqlserver 2005 in Mashad (city in Iran). Is it possible? How can I do it?
    Regards,
    Hamidreza

  10. Hi. I had a slightly different experience. My cron job runs under root, but wanted to run the psql code under postgres user. My script therefore had to be changed to (Note the PGPASSWORD being set AND removed at the end):

    #!/bin/bash
    export PGPASSWORD=XXXXX
    DIR=/home/ben/backups/psql
    [ !$DIR ] && mkdir -p $DIR || :
    LIST=$(su postgres -c “psql -lt” |awk ‘{ print $1}’ |grep -vE ‘^-|^List|^Name|template[0|1]’)
    for d in $LIST
    do
    pg_dump -U postgres $d | gzip -c > $DIR/$d.out.gz
    done
    export PGPASSWORD=

  12. Nice,
    For my case, I add split to have many files and can store it in dumy filesystem
    pg_dumpall -Upostgres | gzip -c | split --bytes=1000m

    Regards

  13. I got errors like this:
    -su: /tmp/pgsql/erpengdemo.sql.gz: Permission denied
    and tish:
    pg_dump: [archiver (db)] connection to database “:” failed: FATAL: database “:” does not exist

    And work around was:

    #!/bin/sh
    DIR=/backup/pgsql
    [ !$DIR ] && mkdir -p $DIR || :

    chown postgres:postgres $DIR

    LIST=$(su – postgres -c “psql -lt” |awk ‘{ print $1}’ |grep -vE ‘^-|:|^List|^Name|template[0|1]’)

    for d in $LIST
    do
    su – postgres -c “/usr/bin/pg_dump $d | gzip -c > $DIR/$d.sql.gz”
    done

  14. I got errors like this:
    -su: /tmp/pgsql/erpengdemo.sql.gz: Permission denied
    and tish:
    pg_dump: [archiver (db)] connection to database “:” failed: FATAL: database “:” does not exist

    And work around was:

    #!/bin/sh
    DIR=/backup/pgsql
    [ !$DIR ] && mkdir -p $DIR || :

    chown postgres:postgres $DIR

    LIST=$(su - postgres -c "psql -lt" |awk '{ print $1}' |grep -vE '^-|:|^List|^Name|template[0|1]')

    for d in $LIST
    do
    su - postgres -c "/usr/bin/pg_dump $d | gzip -c > $DIR/$d.sql.gz"
    done

  15. My version of script. The differencies:
    1. I am asking psql to output databases without header (-t)
    2. Simplified awk call to get rid of colons

    #!/bin/bash
DIR=/backup/psql
LIST=$(psql -l -t -U root | awk 'NF >=5 { print $1}')
for d in $LIST; do
  pg_dump $d | gzip -c >  $DIR/$d.out.gz
done

  16. Even better version 🙂

    #!/bin/bash
#
# Dayly PostgreSQL maintainance: vacuuming and backuping.
#
##

set -e

for DB in $(psql -l -t -U root | awk 'NF >=5 { print $1}' | grep -v template0); do
  echo "[`date`] Maintaing $DB"
  echo 'VACUUM' | psql -U root -d $DB
  DUMP="$DB.`date '+%Y%m%d'`.sql.gz"
  PREV="$DB.`date -d'1 day ago' '+%Y%m%d'`.sql.gz"
  pg_dump -U root $DB | gzip -c > $DUMP
  md5sum -b $DUMP > $DUMP.md5
  if [ -f $PREV.md5 ] && diff $PREV.md5 $DUMP.md5; then
    rm $DUMP $DUMP.md5
  fi
done

    1. I’ve made some script good for cron… It also has impemented restore commands for created backups 🙂 and expiration limit (rotating)

      
#!/bin/bash
#
# Little script for PGSQLdump all databases (seperate files)
#
# v20100519 -- initial version by Koco
#
############################################################
MYEXECNAME=backup_postgres_v8.4_dbs_script.bash

USER=postgres
PGSQLCMD="/postgres1/v8.4.0/bin/psql --port 5433"
PGSQLCMDlist="$PGSQLCMD -l -t"
PGSQLdumpCMD="/postgres1/v8.4.0/bin/pg_dump --port 5433 -C"

APPEND=`date "+%Y%m%d-%H%M"`
BASEDIR=/postgres1/BACKUPS
BKPDIR=$BASEDIR/bkpV8.4.$APPEND
RSTFILE=$BASEDIR/bkpV8.4.$APPEND/1_restore_commands.README

#How many days do you wanna keep backups
TRESHOLD=30

if [ -f /postgres1/.postvolume ]
then
 DATABASES=`su - $USER -c "$PGSQLCMDlist" |grep | |awk '{ print $1}'| grep -vE '^-|^List|^Name|template[0|1]'`
 mkdir $BKPDIR
 for db in $DATABASES
 do
   su - $USER -c "$PGSQLdumpCMD $db" | bzip2 -c > $BKPDIR/$db.dump.bz2
   echo "#---restore $db" >> $RSTFILE
   echo "bzcat $BKPDIR/$db.dump.bz2 > $BASEDIR/RST.dump.sql" >> $RSTFILE
   echo "su - $USER -c "$PGSQLCMD -d $db -f $BASEDIR/RST.dump.sql" " >> $RSTFILE
   echo "rm $BASEDIR/RST.dump.sql" >> $RSTFILE
   echo "#" >> $RSTFILE
 done
fi


# And find those old ones... and delete them (use nwrecover if you need them back)
FILES=`find $BASEDIR -type d -name 'bkpV8.4.*' -mtime +$TRESHOLD`
for f in $FILES
do
  echo "$APPEND: Treshold reached. Removed $f backup." >> $BASEDIR/$MYEXECNAME.log
  rm -rf $f
done

  17. Hi,
    I’m having problems with script and commands. could you help me with it?

    #!/bin/bash
    DIR=”/var/lib/pgsql”
    BASE=”coupons”
    DATE=”date +%m%d”

    pg_dump $BASE | gzip > $DATE.coupons.gz
    exit

  18. Hello,

    We were using the PostgreSQL for Bugzill, Now we lost the Password Doc, how can we take the backup of the database,
    We have the root password

    regards

  21. Hi everyone,
    I am new to freebsd, and I used postgresql for my database management.
    There was this scenario that i accidentally delete this particular database
    and the backup setting for our server is not one by one, meaning all databases.

    My question is how can I restore that particular database using the backup file which is a compressed file which is composed of several database?
    Is there a way to extract a particular database on that file?

  23. Another version to get the list of databases:
    psql -lqt | grep -vE ‘^ +(template[0-9]+|postgres)? *|’ | cut -d’|’ -f1| sed -e ‘s/ //g’ -e ‘/^$/d’

    As my `psql -lqt` output is:
    abcdefghij | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
    postgres | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
    template0 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres +
    | | | | | postgres=CTc/postgres
    template1 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres +
    | | | | | postgres=CTc/postgres
    abc | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 |

    1. In your current directory. When you type the command from directory “/home/michael”, the backup will be in this dir.

  26. HI,

    > Does RHEL supports auto backup and restoration for PostgreSQL? If yes how to configure.
    > Does Ubuntu supports auto backup and restoration for PostgreSQL? If yes how to configure.

    Thanks
    Tilak

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