Developer's Frequently Asked Questions (FAQ) for PostgreSQL

Last updated:Mon Mar 19 12:52:30 EDT 2007

Last updated:Sat May 5 00:09:15 EDT 2007

Current maintainer: Bruce Momjian (bruce@momjian.us)

1.2) What development environment is required to develop code?

1.3) What areas need work?

1.4) What do I do after choosing an item to work on?

1.5) I've developed a patch, what next?

1.6) Where can I learn more about the code?

1.7) How do I download/update the current source tree?

1.8) How do I test my changes?

1.9) What tools are available for developers?

1.10) What books are good for developers?

1.11) What is configure all about?

1.12) How do I add a new port?

1.13) Why don't you use threads, raw devices, async-I/O, <insert your

1.5) I have developed a patch, what next?

1.6) How is a patch reviewed?

1.7) Where can I learn more about the code?

1.8) How do I download/update the current source tree?

1.9) How do I test my changes?

1.10) What tools are available for developers?

1.11) What books are good for developers?

1.12) What is configure all about?

1.13) How do I add a new port?

1.14) Why don't you use threads, raw devices, async-I/O, <insert your

favorite wizz-bang feature here>?

1.14) How are RPM's packaged?

1.15) How are CVS branches handled?

1.16) Where can I get a copy of the SQL standards?

1.17) Where can I get technical assistance?

1.18) How do I get involved in PostgreSQL web site development?

1.19) Why haven't you replaced CVS with SVN, Git, Monotone, VSS,

1.15) How are RPM's packaged?

1.16) How are CVS branches handled?

1.17) Where can I get a copy of the SQL standards?

1.18) Where can I get technical assistance?

1.19) How do I get involved in PostgreSQL web site development?

1.20) Why haven't you replaced CVS with SVN, Git, Monotone, VSS,

<insert your favorite SCM system here>?

Technical Questions

1.1) How do I get involved in PostgreSQL development?

Download the code and have a look around. See 1.7.

Download the code and have a look around. See 1.8.

Subscribe to and read the pgsql-hackers mailing list (often termed

'hackers'). This is where the major contributors and core members of

http://www.postgresql.org/docs/faqs.TODO.html.

You can learn more about these features by consulting the archives,

the SQL standards and the recommend texts (see 1.10).

the SQL standards and the recommend texts (see 1.11).

1.4) What do I do after choosing an item to work on?

being kept for the next release,

http://momjian.postgresql.org/cgi-bin/pgpatches_hold.

1.5) I've developed a patch, what next?

1.5) I have developed a patch, what next?

You will need to submit the patch to pgsql-patches@postgresql.org. It

will be reviewed by other contributors to the project and will be

make sure your submission conforms to the following guidelines:

1. Ensure that your patch is generated against the most recent

version of the code, which for developers is CVS HEAD. For more on

branches in PostgreSQL, see 1.15.

branches in PostgreSQL, see 1.16.

2. Try to make your patch as readable as possible by following the

project's code-layout conventions. This makes it easier for the

reviewer, and there's no point in trying to layout things

6. If you are adding a new feature, confirm that it has been tested

thoroughly. Try to test the feature in all conceivable scenarios.

7. New feature patches should also be accompanied by documentation

patches. If you need help checking the SQL standard, see 1.16.

patches. If you need help checking the SQL standard, see 1.17.

8. Provide an implementation overview, preferably in code comments.

Following the surrounding code commenting style is usually a good

approach.

You will be notified via email when the patch is applied, and your

name will appear in the next version of the release notes.

1.6) Where can I learn more about the code?

1.6) How is a patch reviewed?

Patch committers check several things before applying a patch:

* Patch follows the SQL standard or community agreed-upon behavior

* Style merges seamlessly into the surrounding code

* Written as simply and efficiently as possible

* Uses the available PostgreSQL subsystems properly

* Contains sufficient comments

* Contains code that works on all supported operating systems

* Has proper documentation

* Passes all regression tests

* Behaves as expected, even under unusual cirumstances

* Contains no reliability risks

* Does not overly complicate the source code

* If performance-related, has a measureable performance benefit

* Is of sufficient usefulness to the average PostgreSQL user

* Follows existing PostgreSQL coding standards

1.7) Where can I learn more about the code?

Other than documentation in the source tree itself, you can find some

papers/presentations discussing the code at

http://www.postgresql.org/developer. An excellent presentation is at

http://neilconway.org/talks/hacking/

1.7) How do I download/update the current source tree?

1.8) How do I download/update the current source tree?

There are several ways to obtain the source tree. Occasional

developers can just get the most recent source tree snapshot from

in CVS. For details of how to obtain the source from CVS see

http://developer.postgresql.org/docs/postgres/cvs.html.

1.8) How do I test my changes?

1.9) How do I test my changes?

Basic system testing

you are using GCC you can use the --enable-depend option of configure

to have the compiler compute the dependencies automatically.

1.9) What tools are available for developers?

1.10) What tools are available for developers?

First, all the files in the src/tools directory are designed for

developers.

is also a script called unused_oids in pgsql/src/include/catalog that

shows the unused oids.

1.10) What books are good for developers?

1.11) What books are good for developers?

I have four good books, An Introduction to Database Systems, by C.J.

Date, Addison, Wesley, A Guide to the SQL Standard, by C.J. Date, et.

There is also a database performance site, with a handbook on-line

written by Jim Gray at http://www.benchmarkresources.com..

1.11) What is configure all about?

1.12) What is configure all about?

The files configure and configure.in are part of the GNU autoconf

package. Configure allows us to test for various capabilities of the

removed, so you see only the file contained in the source

distribution.

1.12) How do I add a new port?

1.13) How do I add a new port?

There are a variety of places that need to be modified to add a new

port. First, start in the src/template directory. Add an appropriate

src/makefiles directory for port-specific Makefile handling. There is

a backend/port directory if you need special files for your OS.

1.13) Why don't you use threads, raw devices, async-I/O, <insert your

1.14) Why don't you use threads, raw devices, async-I/O, <insert your

favorite wizz-bang feature here>?

There is always a temptation to use the newest operating system

cautious about their adoption. The TODO list often contains links to

discussions showing our reasoning in these areas.

1.14) How are RPMs packaged?

1.15) How are RPMs packaged?

This was written by Lamar Owen and Devrim Gündüz:

As to why all these files aren't part of the source tree, well, unless

there was a large cry for it to happen, we don't believe it should.

1.15) How are CVS branches managed?

1.16) How are CVS branches managed?

This was written by Tom Lane:

tree right away after a major release --- we wait for a dot-release or

two, so that we won't have to double-patch the first wave of fixes.

1.16) Where can I get a copy of the SQL standards?

1.17) Where can I get a copy of the SQL standards?

There are three versions of the SQL standard: SQL-92, SQL:1999, and

SQL:2003. They are endorsed by ANSI and ISO. Draft versions can be

* http://www.contrib.andrew.cmu.edu/~shadow/sql.html#syntax (SQL-92)

* http://dbs.uni-leipzig.de/en/lokal/standards.pdf (paper)

1.17) Where can I get technical assistance?

1.18) Where can I get technical assistance?

Many technical questions held by those new to the code have been

answered on the pgsql-hackers mailing list - the archives of which can

questions about development of new features, on IRC at

irc.freenode.net in the #postgresql channel.

1.18) How do I get involved in PostgreSQL web site development?

1.19) How do I get involved in PostgreSQL web site development?

PostgreSQL website development is discussed on the

pgsql-www@postgresql.org mailing list. The is a project page where the

source code is available at

http://gborg.postgresql.org/project/pgweb/projdisplay.php , the code

for the next version of the website is under the "portal" module.

1.19) Why haven't you replaced CVS with SVN, Git, Monotone, VSS, <insert your

1.20) Why haven't you replaced CVS with SVN, Git, Monotone, VSS, <insert your

favorite SCMS here>?

Currently the core developers see no SCMS that will provide enough

those structures (in particular, the files copyfuncs.c and

equalfuncs.c. Make sure you add support for your new field to these

files. Find any other places the structure might need code for your

new field. mkid is helpful with this (see 1.9).

new field. mkid is helpful with this (see 1.10).

2.5) Why do we use palloc() and pfree() to allocate memory?