PostgreSQL: Database Creation & Administration

Database Cluster

-        a database storage area on disk. (SQL uses the term catalog cluster.)

-       a collection of databases that is managed by a single instance of a running database server.

-       After initialization, a database cluster will contain a database named postgres, which is meant as a default database for use by utilities, users and third party applications.

-       Another database created within each cluster during initialization is called template1. As the name suggests, this will be used as a template for subsequently created databases; it should not be used for actual work.

-       In file system terms, a database cluster will be a single directory under which all data will be stored. We call this the data directory or data area.

-       Initdb : To initialize a database cluster

Creating a Database Cluster

-bash-3.00$ initdb -D /u01/postgres/postgres/9.0-pgdg/data

The files belonging to this database system will be owned by user "postgresql".

This user must also own the server process.

The database cluster will be initialized with locale C.

The default database encoding has accordingly been set to SQL_ASCII.

The default text search configuration will be set to "english".

creating directory /u01/postgres/postgres/9.0-pgdg/data ... ok

creating subdirectories ... ok

selecting default max_connections ... 100

selecting default shared_buffers ... 32MB

creating configuration files ... ok

creating template1 database in /u01/postgres/postgres/9.0-pgdg/data/base/1 ... ok

initializing pg_authid ... ok

initializing dependencies ... ok

creating system views ... ok

loading system objects' descriptions ... ok

creating conversions ... ok

creating dictionaries ... ok

setting privileges on built-in objects ... ok

creating information schema ... ok

loading PL/pgSQL server-side language ... ok

vacuuming database template1 ... ok

copying template1 to template0 ... ok

copying template1 to postgres ... ok

WARNING: enabling "trust" authentication for local connections

You can change this by editing pg_hba.conf or using the -A option the

next time you run initdb.

Success. You can now start the database server using:

    postgres -D /u01/postgres/postgres/9.0-pgdg/data

or

    pg_ctl -D /u01/postgres/postgres/9.0-pgdg/data -l logfile start

-bash-3.00$

Alternatively, you can run initdb via the pg_ctl program like so:

$ pg_ctl   -D    /u01/postgres/postgres/9.0-pgdg/data   initdb

Best practice:

root# mkdir /usr/local/pgsql/data

root# chown postgres /usr/local/pgsql/data

root# su postgres

postgres$ initdb -D /usr/local/pgsql/data

Starting/stopping Database Server/Cluster

Command to start:  pg_ctl -D /u01/postgres/postgres/9.0-pgdg/data -l logfile start

                                  pg_ctl -D /u01/postgres/postgres/9.0-pgdg/data start

Command to stop:  pg_ctl -D /u01/postgres/postgres/9.0-pgdg/data -l logfile stop

                                   pg_ctl -D /u01/postgres/postgres/9.0-pgdg/data -m f stop

Starting/stopping with a different port:

In postgresql.conf file

listen_addresses = '127.0.0.1'  

port = 5433

Localhost does not work here

Also, put PGPORT = 5433 in .bash_profile

pg_ctl -D /u01/postgres/postgres/9.0-pgdg/data –m f stop

pg_ctl -D /u01/postgres/postgres/9.0-pgdg/data -o "-F -p 5433" start

-bash-3.00$

-bash-3.00$

-bash-3.00$ ps -ef|grep postgres

postgres 21992 21565   0 18:56:22 pts/1       0:00 grep postgres

postgres 21991 21565   0 18:56:22 pts/1       0:00 ps -ef

postgres 21565 21534   0 18:55:18 pts/1       0:00 -bash

postgres 21534 21533   0 18:55:07 ?           0:00 /usr/lib/ssh/sshd

-bash-3.00$

-bash-3.00$

-bash-3.00$ pg_ctl -D /u01/postgres/postgres/9.0-pgdg/data -l logfile start

postmaster starting

-bash-3.00$

-bash-3.00$

-bash-3.00$ ps -ef|grep postgres

postgres 22044 21565   0 18:56:39 pts/1       0:00 ps -ef

postgres 22045 21565   0 18:56:39 pts/1       0:00 grep postgres

postgres 21565 21534   0 18:55:18 pts/1       0:00 -bash

postgres 21534 21533   0 18:55:07 ?           0:00 /usr/lib/ssh/sshd

-bash-3.00$

-bash-3.00$

-bash-3.00$ echo $PATH

/usr/bin:/opt/EMCpower/bin:/etc/emc/bin:/etc

-bash-3.00$

-bash-3.00$ cd /u01/postgres/postgres/9.0-pgdg/bin/64/

-bash-3.00$

-bash-3.00$ pwd

/u01/postgres/postgres/9.0-pgdg/bin/64

-bash-3.00$

-bash-3.00$ export PATH=/u01/postgres/postgres/9.0-pgdg/bin/64:/usr/bin:/opt/EMCpower/bin:/etc/emc/bin:/etc

-bash-3.00$

-bash-3.00$ pg_ctl -D /u01/postgres/postgres/9.0-pgdg/data -l logfile start

server starting

-bash-3.00$

-bash-3.00$ ps -ef|grep postgres

postgres 22692 21565   0 18:58:47 pts/1       0:00 ps -ef

postgres 22657 22652   0 18:58:37 ?           0:00 /u01/postgres/postgres/9.0-pgdg/bin/64/postgres -D /u01/postgres/postgres/9.0-p

postgres 22652     1   0 18:58:37 pts/1       0:00 /u01/postgres/postgres/9.0-pgdg/bin/64/postgres -D /u01/postgres/postgres/9.0-p

postgres 22655 22652   0 18:58:37 ?           0:00 /u01/postgres/postgres/9.0-pgdg/bin/64/postgres -D /u01/postgres/postgres/9.0-p

postgres 22656 22652   0 18:58:37 ?           0:00 /u01/postgres/postgres/9.0-pgdg/bin/64/postgres -D /u01/postgres/postgres/9.0-p

postgres 21565 21534   0 18:55:18 pts/1       0:00 -bash

postgres 21534 21533   0 18:55:07 ?           0:00 /usr/lib/ssh/sshd

postgres 22654 22652   0 18:58:37 ?           0:00 /u01/postgres/postgres/9.0-pgdg/bin/64/postgres -D /u01/postgres/postgres/9.0-p

postgres 22693 21565   0 18:58:47 pts/1       0:00 grep postgres

-bash-3.00$

Connecting to psql

-bash-3.00$ export PATH=/u01/postgres/postgres/9.0-pgdg/bin/64:/usr/bin:/opt/EMCpower/bin:/etc/emc/bin:/etc

-bash-3.00$

-bash-3.00$ psql postgres

psql (9.0.4)

Type "help" for help.

postgres=#

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Important Configuration Files:

postgresql.conf (under /u01/postgres/postgres/9.0-pgdg/data)

listen_addresses : from which address server will respond

pg_hba.conf (under /u01/postgres/postgres/9.0-pgdg/data)

host based authentication

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