Frequently Asked Questions (FAQ) for PostgreSQL
- Last updated: Fri Mar 12 08:51:11 EST 2004
+ Last updated: Mon Mar 29 00:07:11 EST 2004
1.1) What is PostgreSQL? How is it pronounced?
- PostgreSQL is pronounced Post-Gres-Q-L. The name "Postgres" is also
- used in conversation.
+ PostgreSQL is pronounced Post-Gres-Q-L. An audio file is available at
+ http://www.postgresql.org/postgresql.mp3 for those would like to hear
+ the pronunciation.
PostgreSQL is an enhancement of the POSTGRES database management
- system, a next-generation DBMS research prototype. While PostgreSQL
- retains the powerful data model and rich data types of POSTGRES, it
- replaces the PostQuel query language with an extended subset of SQL.
- PostgreSQL is free and the complete source is available.
+ system (and is still sometimes reffered to as simply "Postgres"), a
+ next-generation DBMS research prototype. While PostgreSQL retains the
+ powerful data model and rich data types of POSTGRES, it replaces the
+ PostQuel query language with an extended subset of SQL. PostgreSQL is
+ free and the complete source is available.
PostgreSQL development is performed by a team of developers who all
subscribe to the PostgreSQL development mailing list. The current
1.6 on how to join). This team is now responsible for all development
of PostgreSQL. It is a community project and is not controlled by any
- company. To get involved, see the developer's
- FAQ,http://www.PostgreSQL.org/docs/faqs/FAQ_DEV.html
+ company. To get involved, see the developer's FAQ at
+ http://www.PostgreSQL.org/docs/faqs/FAQ_DEV.html
The authors of PostgreSQL 1.01 were Andrew Yu and Jolly Chen. Many
others have contributed to the porting, testing, debugging, and
PostgreSQL Data Base Management System
- Portions copyright (c) 1996-2002, PostgreSQL Global Development Group
+ Portions copyright (c) 1996-2004, PostgreSQL Global Development Group
Portions Copyright (c) 1994-6 Regents of the University of California
Permission to use, copy, modify, and distribute this software and its
1.3) What Unix platforms does PostgreSQL run on?
- In general, a modern Unix-compatible platform should be able to run
+ In general, any modern Unix-compatible platform should be able to run
PostgreSQL. The platforms that had received explicit testing at the
time of release are listed in the installation instructions.
These include PgAccess http://www.pgaccess.org), PgAdmin III
(http://www.pgadmin.org, RHDB Admin (http://sources.redhat.com/rhdb/ )
and Rekall ( http://www.thekompany.com/products/rekall/, proprietary).
- There is also PHPPgAdmin ( http://phppgadmin.sourceforge.net/ ), a
+ There is also PhpPgAdmin ( http://phppgadmin.sourceforge.net/ ), a
web-based interface to PostgreSQL.
See http://techdocs.postgresql.org/guides/GUITools for a more detailed
By default, PostgreSQL only allows connections from the local machine
using Unix domain sockets. Other machines will not be able to connect
- unless you add the -i flag to postmaster, and enable host-based
- authentication by modifying the file $PGDATA/pg_hba.conf accordingly.
- This will allow TCP/IP connections.
+ unless you turn on tcpip_sockets in the postgresql.conf and enable
+ host-based authentication by modifying the file $PGDATA/pg_hba.conf
+ accordingly. This will allow TCP/IP connections.
3.6) How do I tune the database engine for better performance?
- Certainly, indexes can speed up queries. The EXPLAIN command allows
- you to see how PostgreSQL is interpreting your query, and which
+ Certainly, indexes can speed up queries. The EXPLAIN ANALYZE command
+ allows you to see how PostgreSQL is interpreting your query, and which
indexes are being used.
If you are doing many INSERTs, consider doing them in a large batch
4.3) How do I get a list of tables or other things I can see in psql?
- You can read the source code for psql in file
- pgsql/src/bin/psql/describe.c. It contains SQL commands that generate
- the output for psql's backslash commands. You can also start psql with
- the -E option so it will print out the queries it uses to execute the
- commands you give.
+ Use the \dt command to see tables in psql. For a complete list of
+ commands inside psql you can use \?. Alternatively you can read the
+ source code for psql in file pgsql/src/bin/psql/describe.c, it
+ contains SQL commands that generate the output for psql's backslash
+ commands. You can also start psql with the -E option so it will print
+ out the queries it uses to execute the commands you give. PostgreSQL
+ also provides an SQLi compliant INFORMATION SCHEMA interface you can
+ query to get information about the database.
4.4) How do you remove a column from a table, or change its data type?