Replace developer FAQ with a reference to the wiki, which is where

it now lives (per discussion). Leave the other FAQs alone for now.

1 files changed, 2 insertions, 812 deletions

diff --git a/doc/FAQ_DEV b/doc/FAQ_DEV
index ac8b8ff0aeb..3f2070aff80 100644
--- a/doc/FAQ_DEV
+++ b/doc/FAQ_DEV
@@ -1,813 +1,3 @@
+The developer FAQ can be found on the PostgreSQL wiki:
 
-          Developer's Frequently Asked Questions (FAQ) for PostgreSQL
-                                       
-   Last updated: Thu Oct 27 09:48:14 EDT 2005
-   
-   Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
-   
-   The most recent version of this document can be viewed at
-   http://www.postgresql.org/files/documentation/faqs/FAQ_DEV.html.
-     _________________________________________________________________
-   
-General Questions
-
-   1.1) How do I get involved in PostgreSQL development?
-   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
-   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?
-   
-Technical Questions
-
-   2.1) How do I efficiently access information in tables from the
-   backend code?
-   2.2) Why are table, column, type, function, view names sometimes
-   referenced as Name or NameData, and sometimes as char *?
-   2.3) Why do we use Node and List to make data structures?
-   2.4) I just added a field to a structure. What else should I do?
-   2.5) Why do we use palloc() and pfree() to allocate memory?
-   2.6) What is ereport()?
-   2.7) What is CommandCounterIncrement()?
-   2.8) What debugging features are available?
-     _________________________________________________________________
-   
-General Questions
-
-  1.1) How do I get involved in PostgreSQL development?
-  
-   Download the code and have a look around. See 1.7.
-   
-   Subscribe to and read the pgsql-hackers mailing list (often termed
-   'hackers'). This is where the major contributors and core members of
-   the project discuss development.
-   
-  1.2) What development environment is required to develop code?
-  
-   PostgreSQL is developed mostly in the C programming language. It also
-   makes use of Yacc and Lex.
-   
-   The source code is targeted at most of the popular Unix platforms and
-   the Windows environment (XP, Windows 2000, and up).
-   
-   Most developers make use of the open source development tool chain. If
-   you have contributed to open source software before, you will probably
-   be familiar with these tools. They include: GCC (http://gcc.gnu.org,
-   GDB (www.gnu.org/software/gdb/gdb.html), autoconf
-   (www.gnu.org/software/autoconf/) AND GNU make
-   (www.gnu.org/software/make/make.html.
-   
-   Developers using this tool chain on Windows make use of MingW (see
-   http://www.mingw.org/).
-   
-   Some developers use compilers from other software vendors with mixed
-   results.
-   
-   Developers who are regularly rebuilding the source often pass the
-   --enable-depend flag to configure. The result is that when you make a
-   modification to a C header file, all files depend upon that file are
-   also rebuilt.
-   
-  1.3) What areas need work?
-  
-   Outstanding features are detailed in the TODO list. This is located in
-   doc/TODO in the source distribution or at
-   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).
-   
-  1.4) What do I do after choosing an item to work on?
-  
-   Send an email to pgsql-hackers with a proposal for what you want to do
-   (assuming your contribution is not trivial). Working in isolation is
-   not advisable because others might be working on the same TODO item,
-   or you might have misunderstood the TODO item. In the email, discuss
-   both the internal implementation method you plan to use, and any
-   user-visible changes (new syntax, etc). For complex patches, it is
-   important to get community feeback on your proposal before starting
-   work. Failure to do so might mean your patch is rejected.
-   
-   A web site is maintained for patches awaiting review,
-   http://momjian.postgresql.org/cgi-bin/pgpatches, and those that are
-   being kept for the next release,
-   http://momjian.postgresql.org/cgi-bin/pgpatches2.
-   
-  1.5) I've developed a patch, what next?
-  
-   Generate the patch in contextual diff format. If you are unfamiliar
-   with this, you might find the script src/tools/makediff/difforig
-   useful.
-   
-   Ensure that your patch is generated against the most recent version of
-   the code. If it is a patch adding new functionality, the most recent
-   version is CVS HEAD; if it is a bug fix, this will be the most
-   recently version of the branch which suffers from the bug (for more on
-   branches in PostgreSQL, see 1.15).
-   
-   Finally, submit the patch to pgsql-patches@postgresql.org. It will be
-   reviewed by other contributors to the project and will be either
-   accepted or sent back for further work. Also, please try to include
-   documentation changes as part of the patch. If you can't do that, let
-   us know and we will manually update the documentation when the patch
-   is applied.
-   
-  1.6) 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.
-   
-  1.7) 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
-   ftp://ftp.postgresql.org.
-   
-   Regular developers might want to take advantage of anonymous access to
-   our source code management system. The source tree is currently hosted
-   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?
-  
-   Basic system testing
-   
-   The easiest way to test your code is to ensure that it builds against
-   the latest version of the code and that it does not generate compiler
-   warnings.
-   
-   It is worth advised that you pass --enable-cassert to configure. This
-   will turn on assertions with in the source which will often show us
-   bugs because they cause data corruption of segmentation violations.
-   This generally makes debugging much easier.
-   
-   Then, perform run time testing via psql.
-   
-   Regression test suite
-   
-   The next step is to test your changes against the existing regression
-   test suite. To do this, issue "make check" in the root directory of
-   the source tree. If any tests failure, investigate.
-   
-   If you've deliberately changed existing behavior, this change might
-   cause a regression test failure but not any actual regression. If so,
-   you should also patch the regression test suite.
-   
-   Other run time testing
-   
-   Some developers make use of tools such as valgrind
-   (http://valgrind.kde.org) for memory testing, gprof (which comes with
-   the GNU binutils suite) and oprofile
-   (http://oprofile.sourceforge.net/) for profiling and other related
-   tools.
-   
-   What about unit testing, static analysis, model checking...?
-   
-   There have been a number of discussions about other testing frameworks
-   and some developers are exploring these ideas.
-   
-   Keep in mind the Makefiles do not have the proper dependencies for
-   include files. You have to do a make clean and then another make. If
-   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?
-  
-   First, all the files in the src/tools directory are designed for
-   developers.
-    RELEASE_CHANGES changes we have to make for each release
-    backend         description/flowchart of the backend directories
-    ccsym           find standard defines made by your compiler
-     copyright       fixes copyright notices
-
-    entab           converts tabs to spaces, used by pgindent
-    find_static     finds functions that could be made static
-    find_typedef    finds typedefs in the source code
-    find_badmacros  finds macros that use braces incorrectly
-    fsync           a script to provide information about the cost of cache
-                     syncing system calls
-    make_ctags      make vi 'tags' file in each directory
-    make_diff       make *.orig and diffs of source
-    make_etags      make emacs 'etags' files
-    make_keywords   make comparison of our keywords and SQL'92
-    make_mkid       make mkid ID files
-    pgcvslog        used to generate a list of changes for each release
-    pginclude       scripts for adding/removing include files
-    pgindent        indents source files
-    pgtest          a semi-automated build system
-    thread          a thread testing script
-
-   In src/include/catalog:
-    unused_oids     a script which generates unused OIDs for use in system
-                     catalogs
-    duplicate_oids  finds duplicate OIDs in system catalog definitions
-
-   If you point your browser at the tools/backend/index.html file, you
-   will see few paragraphs describing the data flow, the backend
-   components in a flow chart, and a description of the shared memory
-   area. You can click on any flowchart box to see a description. If you
-   then click on the directory name, you will be taken to the source
-   directory, to browse the actual source code behind it. We also have
-   several README files in some source directories to describe the
-   function of the module. The browser will display these when you enter
-   the directory also. The tools/backend directory is also contained on
-   our web page under the title How PostgreSQL Processes a Query.
-   
-   Second, you really should have an editor that can handle tags, so you
-   can tag a function call to see the function definition, and then tag
-   inside that function to see an even lower-level function, and then
-   back out twice to return to the original function. Most editors
-   support this via tags or etags files.
-   
-   Third, you need to get id-utils from ftp://ftp.gnu.org/gnu/id-utils/
-   
-   By running tools/make_mkid, an archive of source symbols can be
-   created that can be rapidly queried.
-   
-   Some developers make use of cscope, which can be found at
-   http://cscope.sf.net/. Others use glimpse, which can be found at
-   http://webglimpse.net/.
-   
-   tools/make_diff has tools to create patch diff files that can be
-   applied to the distribution. This produces context diffs, which is our
-   preferred format.
-   
-   Our standard format is to indent each code level with one tab, where
-   each tab is four spaces. You will need to set your editor to display
-   tabs as four spaces:
-    vi in ~/.exrc:
-            set tabstop=4
-            set sw=4
-    more:
-            more -x4
-    less:
-            less -x4
-    emacs:
-        M-x set-variable tab-width
-
-        or
-
-        (c-add-style "pgsql"
-                '("bsd"
-                        (indent-tabs-mode . t)
-                        (c-basic-offset   . 4)
-                        (tab-width . 4)
-                        (c-offsets-alist .
-                                ((case-label . +)))
-                )
-                nil ) ; t = set this style, nil = don't
-
-        (defun pgsql-c-mode ()
-                (c-mode)
-                (c-set-style "pgsql")
-        )
-
-        and add this to your autoload list (modify file path in macro):
-
-        (setq auto-mode-alist
-                (cons '("\\`/home/andrew/pgsql/.*\\.[chyl]\\'" . pgsql-c-mode)
-                auto-mode-alist))
-        or
-            /*
-             * Local variables:
-             *  tab-width: 4
-             *  c-indent-level: 4
-             *  c-basic-offset: 4
-             * End:
-             */
-
-   pgindent will the format code by specifying flags to your operating
-   system's utility indent. This article describes the value of a
-   consistent coding style.
-   
-   pgindent is run on all source files just before each beta test period.
-   It auto-formats all source files to make them consistent. Comment
-   blocks that need specific line breaks should be formatted as block
-   comments, where the comment starts as /*------. These comments will
-   not be reformatted in any way.
-   
-   pginclude contains scripts used to add needed #include's to include
-   files, and removed unneeded #include's.
-   
-   When adding system types, you will need to assign oids to them. There
-   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?
-  
-   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.
-   al, Addison, Wesley, Fundamentals of Database Systems, by Elmasri and
-   Navathe, and Transaction Processing, by Jim Gray, Morgan, Kaufmann
-   
-   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?
-  
-   The files configure and configure.in are part of the GNU autoconf
-   package. Configure allows us to test for various capabilities of the
-   OS, and to set variables that can then be tested in C programs and
-   Makefiles. Autoconf is installed on the PostgreSQL main server. To add
-   options to configure, edit configure.in, and then run autoconf to
-   generate configure.
-   
-   When configure is run by the user, it tests various OS capabilities,
-   stores those in config.status and config.cache, and modifies a list of
-   *.in files. For example, if there exists a Makefile.in, configure
-   generates a Makefile that contains substitutions for all @var@
-   parameters found by configure.
-   
-   When you need to edit files, make sure you don't waste time modifying
-   files generated by configure. Edit the *.in file, and re-run configure
-   to recreate the needed file. If you run make distclean from the
-   top-level source directory, all files derived by configure are
-   removed, so you see only the file contained in the source
-   distribution.
-   
-  1.12) 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
-   entry for your OS. Also, use src/config.guess to add your OS to
-   src/template/.similar. You shouldn't match the OS version exactly. The
-   configure test will look for an exact OS version number, and if not
-   found, find a match without version number. Edit src/configure.in to
-   add your new OS. (See configure item above.) You will need to run
-   autoconf, or patch src/configure too.
-   
-   Then, check src/include/port and add your new OS file, with
-   appropriate values. Hopefully, there is already locking code in
-   src/include/storage/s_lock.h for your CPU. There is also a
-   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
-  favorite wizz-bang feature here>?
-  
-   There is always a temptation to use the newest operating system
-   features as soon as they arrive. We resist that temptation.
-   
-   First, we support 15+ operating systems, so any new feature has to be
-   well established before we will consider it. Second, most new
-   wizz-bang features don't provide dramatic improvements. Third, they
-   usually have some downside, such as decreased reliability or
-   additional code required. Therefore, we don't rush to use new features
-   but rather wait for the feature to be established, then ask for
-   testing to show that a measurable improvement is possible.
-   
-   As an example, threads are not currently used in the backend code
-   because:
-     * Historically, threads were unsupported and buggy.
-     * An error in one backend can corrupt other backends.
-     * Speed improvements using threads are small compared to the
-       remaining backend startup time.
-     * The backend code would be more complex.
-       
-   So, we are not ignorant of new features. It is just that we are
-   cautious about their adoption. The TODO list often contains links to
-   discussions showing our reasoning in these areas.
-   
-  1.14) How are RPMs packaged?
-  
-   This was written by Lamar Owen:
-   
-   2001-05-03
-   
-   As to how the RPMs are built -- to answer that question sanely
-   requires me to know how much experience you have with the whole RPM
-   paradigm. 'How is the RPM built?' is a multifaceted question. The
-   obvious simple answer is that I maintain:
-    1. A set of patches to make certain portions of the source tree
-       'behave' in the different environment of the RPMset;
-    2. The initscript;
-    3. Any other ancillary scripts and files;
-    4. A README.rpm-dist document that tries to adequately document both
-       the differences between the RPM build and the WHY of the
-       differences, as well as useful RPM environment operations (like,
-       using syslog, upgrading, getting postmaster to start at OS boot,
-       etc);
-    5. The spec file that throws it all together. This is not a trivial
-       undertaking in a package of this size.
-       
-   I then download and build on as many different canonical distributions
-   as I can -- currently I am able to build on Red Hat 6.2, 7.0, and 7.1
-   on my personal hardware. Occasionally I receive opportunity from
-   certain commercial enterprises such as Great Bridge and PostgreSQL,
-   Inc. to build on other distributions.
-   
-   I test the build by installing the resulting packages and running the
-   regression tests. Once the build passes these tests, I upload to the
-   postgresql.org ftp server and make a release announcement. I am also
-   responsible for maintaining the RPM download area on the ftp site.
-   
-   You'll notice I said 'canonical' distributions above. That simply
-   means that the machine is as stock 'out of the box' as practical --
-   that is, everything (except select few programs) on these boxen are
-   installed by RPM; only official Red Hat released RPMs are used (except
-   in unusual circumstances involving software that will not alter the
-   build -- for example, installing a newer non-RedHat version of the Dia
-   diagramming package is OK -- installing Python 2.1 on the box that has
-   Python 1.5.2 installed is not, as that alters the PostgreSQL build).
-   The RPM as uploaded is built to as close to out-of-the-box pristine as
-   is possible. Only the standard released 'official to that release'
-   compiler is used -- and only the standard official kernel is used as
-   well.
-   
-   For a time I built on Mandrake for RedHat consumption -- no more.
-   Nonstandard RPM building systems are worse than useless. Which is not
-   to say that Mandrake is useless! By no means is Mandrake useless --
-   unless you are building Red Hat RPMs -- and Red Hat is useless if
-   you're trying to build Mandrake or SuSE RPMs, for that matter. But I
-   would be foolish to use 'Lamar Owen's Super Special RPM Blend Distro
-   0.1.2' to build for public consumption! :-)
-   
-   I _do_ attempt to make the _source_ RPM compatible with as many
-   distributions as possible -- however, since I have limited resources
-   (as a volunteer RPM maintainer) I am limited as to the amount of
-   testing said build will get on other distributions, architectures, or
-   systems.
-   
-   And, while I understand people's desire to immediately upgrade to the
-   newest version, realize that I do this as a side interest -- I have a
-   regular, full-time job as a broadcast
-   engineer/webmaster/sysadmin/Technical Director which occasionally
-   prevents me from making timely RPM releases. This happened during the
-   early part of the 7.1 beta cycle -- but I believe I was pretty much on
-   the ball for the Release Candidates and the final release.
-   
-   I am working towards a more open RPM distribution -- I would dearly
-   love to more fully document the process and put everything into CVS --
-   once I figure out how I want to represent things such as the spec file
-   in a CVS form. It makes no sense to maintain a changelog, for
-   instance, in the spec file in CVS when CVS does a better job of
-   changelogs -- I will need to write a tool to generate a real spec file
-   from a CVS spec-source file that would add version numbers, changelog
-   entries, etc to the result before building the RPM. IOW, I need to
-   rethink the process -- and then go through the motions of putting my
-   long RPM history into CVS one version at a time so that version
-   history information isn't lost.
-   
-   As to why all these files aren't part of the source tree, well, unless
-   there was a large cry for it to happen, I don't believe it should.
-   PostgreSQL is very platform-agnostic -- and I like that. Including the
-   RPM stuff as part of the Official Tarball (TM) would, IMHO, slant that
-   agnostic stance in a negative way. But maybe I'm too sensitive to
-   that. I'm not opposed to doing that if that is the consensus of the
-   core group -- and that would be a sneaky way to get the stuff into CVS
-   :-). But if the core group isn't thrilled with the idea (and my
-   instinct says they're not likely to be), I am opposed to the idea --
-   not to keep the stuff to myself, but to not hinder the
-   platform-neutral stance. IMHO, of course.
-   
-   Of course, there are many projects that DO include all the files
-   necessary to build RPMs from their Official Tarball (TM).
-   
-  1.15) How are CVS branches managed?
-  
-   This was written by Tom Lane:
-   
-   2001-05-07
-   
-   If you just do basic "cvs checkout", "cvs update", "cvs commit", then
-   you'll always be dealing with the HEAD version of the files in CVS.
-   That's what you want for development, but if you need to patch past
-   stable releases then you have to be able to access and update the
-   "branch" portions of our CVS repository. We normally fork off a branch
-   for a stable release just before starting the development cycle for
-   the next release.
-   
-   The first thing you have to know is the branch name for the branch you
-   are interested in getting at. To do this, look at some long-lived
-   file, say the top-level HISTORY file, with "cvs status -v" to see what
-   the branch names are. (Thanks to Ian Lance Taylor for pointing out
-   that this is the easiest way to do it.) Typical branch names are:
-    REL7_1_STABLE
-    REL7_0_PATCHES
-    REL6_5_PATCHES
-
-   OK, so how do you do work on a branch? By far the best way is to
-   create a separate checkout tree for the branch and do your work in
-   that. Not only is that the easiest way to deal with CVS, but you
-   really need to have the whole past tree available anyway to test your
-   work. (And you *better* test your work. Never forget that dot-releases
-   tend to go out with very little beta testing --- so whenever you
-   commit an update to a stable branch, you'd better be doubly sure that
-   it's correct.)
-   
-   Normally, to checkout the head branch, you just cd to the place you
-   want to contain the toplevel "pgsql" directory and say
-    cvs ... checkout pgsql
-
-   To get a past branch, you cd to wherever you want it and say
-    cvs ... checkout -r BRANCHNAME pgsql
-
-   For example, just a couple days ago I did
-    mkdir ~postgres/REL7_1
-    cd ~postgres/REL7_1
-    cvs ... checkout -r REL7_1_STABLE pgsql
-
-   and now I have a maintenance copy of 7.1.*.
-   
-   When you've done a checkout in this way, the branch name is "sticky":
-   CVS automatically knows that this directory tree is for the branch,
-   and whenever you do "cvs update" or "cvs commit" in this tree, you'll
-   fetch or store the latest version in the branch, not the head version.
-   Easy as can be.
-   
-   So, if you have a patch that needs to apply to both the head and a
-   recent stable branch, you have to make the edits and do the commit
-   twice, once in your development tree and once in your stable branch
-   tree. This is kind of a pain, which is why we don't normally fork the
-   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?
-  
-   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
-   downloaded from:
-     * SQL-92 http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt
-     * SQL:1999
-       http://www.cse.iitb.ac.in/dbms/Data/Papers-Other/SQL1999/ansi-iso-
-       9075-2-1999.pdf
-     * SQL:2003 http://www.wiscorp.com/sql/sql_2003_standard.zip
-       
-   Some SQL standards web pages are:
-     * http://troels.arvin.dk/db/rdbms/links/#standards
-     * http://www.wiscorp.com/SQLStandards.html
-     * 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?
-  
-   Many technical questions held by those new to the code have been
-   answered on the pgsql-hackers mailing list - the archives of which can
-   be found at http://archives.postgresql.org/pgsql-hackers/.
-   
-   If you cannot find discussion or your particular question, feel free
-   to put it to the list.
-   
-   Major contributors also answer technical questions, including
-   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?
-  
-   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. You
-   will also find code for the "techdocs" website if you would like to
-   contribute to that. A temporary todo list for current website
-   development issues is available at http://xzilla.postgresql.org/todo
-   
-Technical Questions
-
-  2.1) How do I efficiently access information in tables from the backend code?
-  
-   You first need to find the tuples(rows) you are interested in. There
-   are two ways. First, SearchSysCache() and related functions allow you
-   to query the system catalogs. This is the preferred way to access
-   system tables, because the first call to the cache loads the needed
-   rows, and future requests can return the results without accessing the
-   base table. The caches use system table indexes to look up tuples. A
-   list of available caches is located in
-   src/backend/utils/cache/syscache.c.
-   src/backend/utils/cache/lsyscache.c contains many column-specific
-   cache lookup functions.
-   
-   The rows returned are cache-owned versions of the heap rows.
-   Therefore, you must not modify or delete the tuple returned by
-   SearchSysCache(). What you should do is release it with
-   ReleaseSysCache() when you are done using it; this informs the cache
-   that it can discard that tuple if necessary. If you neglect to call
-   ReleaseSysCache(), then the cache entry will remain locked in the
-   cache until end of transaction, which is tolerable but not very
-   desirable.
-   
-   If you can't use the system cache, you will need to retrieve the data
-   directly from the heap table, using the buffer cache that is shared by
-   all backends. The backend automatically takes care of loading the rows
-   into the buffer cache.
-   
-   Open the table with heap_open(). You can then start a table scan with
-   heap_beginscan(), then use heap_getnext() and continue as long as
-   HeapTupleIsValid() returns true. Then do a heap_endscan(). Keys can be
-   assigned to the scan. No indexes are used, so all rows are going to be
-   compared to the keys, and only the valid rows returned.
-   
-   You can also use heap_fetch() to fetch rows by block number/offset.
-   While scans automatically lock/unlock rows from the buffer cache, with
-   heap_fetch(), you must pass a Buffer pointer, and ReleaseBuffer() it
-   when completed.
-   
-   Once you have the row, you can get data that is common to all tuples,
-   like t_self and t_oid, by merely accessing the HeapTuple structure
-   entries. If you need a table-specific column, you should take the
-   HeapTuple pointer, and use the GETSTRUCT() macro to access the
-   table-specific start of the tuple. You then cast the pointer as a
-   Form_pg_proc pointer if you are accessing the pg_proc table, or
-   Form_pg_type if you are accessing pg_type. You can then access the
-   columns by using a structure pointer:
-((Form_pg_class) GETSTRUCT(tuple))->relnatts
-
-   You must not directly change live tuples in this way. The best way is
-   to use heap_modifytuple() and pass it your original tuple, and the
-   values you want changed. It returns a palloc'ed tuple, which you pass
-   to heap_replace(). You can delete tuples by passing the tuple's t_self
-   to heap_destroy(). You use t_self for heap_update() too. Remember,
-   tuples can be either system cache copies, which might go away after
-   you call ReleaseSysCache(), or read directly from disk buffers, which
-   go away when you heap_getnext(), heap_endscan, or ReleaseBuffer(), in
-   the heap_fetch() case. Or it may be a palloc'ed tuple, that you must
-   pfree() when finished.
-   
-  2.2) Why are table, column, type, function, view names sometimes referenced
-  as Name or NameData, and sometimes as char *?
-  
-   Table, column, type, function, and view names are stored in system
-   tables in columns of type Name. Name is a fixed-length,
-   null-terminated type of NAMEDATALEN bytes. (The default value for
-   NAMEDATALEN is 64 bytes.)
-typedef struct nameData
-    {
-        char        data[NAMEDATALEN];
-    } NameData;
-    typedef NameData *Name;
-
-   Table, column, type, function, and view names that come into the
-   backend via user queries are stored as variable-length,
-   null-terminated character strings.
-   
-   Many functions are called with both types of names, ie. heap_open().
-   Because the Name type is null-terminated, it is safe to pass it to a
-   function expecting a char *. Because there are many cases where
-   on-disk names(Name) are compared to user-supplied names(char *), there
-   are many cases where Name and char * are used interchangeably.
-   
-  2.3) Why do we use Node and List to make data structures?
-  
-   We do this because this allows a consistent way to pass data inside
-   the backend in a flexible way. Every node has a NodeTag which
-   specifies what type of data is inside the Node. Lists are groups of
-   Nodes chained together as a forward-linked list.
-   
-   Here are some of the List manipulation commands:
-   
-   lfirst(i), lfirst_int(i), lfirst_oid(i)
-          return the data (a point, integer and OID respectively) at list
-          element i.
-          
-   lnext(i)
-          return the next list element after i.
-          
-   foreach(i, list)
-          loop through list, assigning each list element to i. It is
-          important to note that i is a List *, not the data in the List
-          element. You need to use lfirst(i) to get at the data. Here is
-          a typical code snippet that loops through a List containing Var
-          *'s and processes each one:
-          
- List                *list;
-    ListCell    *i;
-
-    foreach(i, list)
-    {
-        Var *var = lfirst(i);
-
-        /* process var here */
-    }
-
-   lcons(node, list)
-          add node to the front of list, or create a new list with node
-          if list is NIL.
-          
-   lappend(list, node)
-          add node to the end of list. This is more expensive that lcons.
-          
-   nconc(list1, list2)
-          Concat list2 on to the end of list1.
-          
-   length(list)
-          return the length of the list.
-          
-   nth(i, list)
-          return the i'th element in list.
-          
-   lconsi, ...
-          There are integer versions of these: lconsi, lappendi, etc.
-          Also versions for OID lists: lconso, lappendo, etc.
-          
-   You can print nodes easily inside gdb. First, to disable output
-   truncation when you use the gdb print command:
-(gdb) set print elements 0
-
-   Instead of printing values in gdb format, you can use the next two
-   commands to print out List, Node, and structure contents in a verbose
-   format that is easier to understand. List's are unrolled into nodes,
-   and nodes are printed in detail. The first prints in a short format,
-   and the second in a long format:
-(gdb) call print(any_pointer)
-    (gdb) call pprint(any_pointer)
-
-   The output appears in the postmaster log file, or on your screen if
-   you are running a backend directly without a postmaster.
-   
-  2.4) I just added a field to a structure. What else should I do?
-  
-   The structures passing around from the parser, rewrite, optimizer, and
-   executor require quite a bit of support. Most structures have support
-   routines in src/backend/nodes used to create, copy, read, and output
-   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).
-   
-  2.5) Why do we use palloc() and pfree() to allocate memory?
-  
-   palloc() and pfree() are used in place of malloc() and free() because
-   we find it easier to automatically free all memory allocated when a
-   query completes. This assures us that all memory that was allocated
-   gets freed even if we have lost track of where we allocated it. There
-   are special non-query contexts that memory can be allocated in. These
-   affect when the allocated memory is freed by the backend.
-   
-  2.6) What is ereport()?
-  
-   ereport() is used to send messages to the front-end, and optionally
-   terminate the current query being processed. The first parameter is an
-   ereport level of DEBUG (levels 1-5), LOG, INFO, NOTICE, ERROR, FATAL,
-   or PANIC. NOTICE prints on the user's terminal and the postmaster
-   logs. INFO prints only to the user's terminal and LOG prints only to
-   the server logs. (These can be changed from postgresql.conf.) ERROR
-   prints in both places, and terminates the current query, never
-   returning from the call. FATAL terminates the backend process. The
-   remaining parameters of ereport are a printf-style set of parameters
-   to print.
-   
-   ereport(ERROR) frees most memory and open file descriptors so you
-   don't need to clean these up before the call.
-   
-  2.7) What is CommandCounterIncrement()?
-  
-   Normally, transactions can not see the rows they modify. This allows
-   UPDATE foo SET x = x + 1 to work correctly.
-   
-   However, there are cases where a transactions needs to see rows
-   affected in previous parts of the transaction. This is accomplished
-   using a Command Counter. Incrementing the counter allows transactions
-   to be broken into pieces so each piece can see rows modified by
-   previous pieces. CommandCounterIncrement() increments the Command
-   Counter, creating a new part of the transaction.
-   
-  2.8) What debugging features are available?
-  
-   First, try running configure with the --enable-cassert option, many
-   assert()s monitor the progress of the backend and halt the program
-   when something unexpected occurs.
-   
-   The postmaster has a -d option that allows even more detailed
-   information to be reported. The -d option takes a number that
-   specifies the debug level. Be warned that high debug level values
-   generate large log files.
-   
-   If the postmaster is not running, you can actually run the postgres
-   backend from the command line, and type your SQL statement directly.
-   This is recommended only for debugging purposes. If you have compiled
-   with debugging symbols, you can use a debugger to see what is
-   happening. Because the backend was not started from postmaster, it is
-   not running in an identical environment and locking/backend
-   interaction problems might not be duplicated.
-   
-   If the postmaster is running, start psql in one window, then find the
-   PID of the postgres process used by psql using SELECT
-   pg_backend_pid(). Use a debugger to attach to the postgres PID. You
-   can set breakpoints in the debugger and issue queries from the other.
-   If you are looking to find the location that is generating an error or
-   log message, set a breakpoint at errfinish. psql. If you are debugging
-   postgres startup, you can set PGOPTIONS="-W n", then start psql. This
-   will cause startup to delay for n seconds so you can attach to the
-   process with the debugger, set any breakpoints, and continue through
-   the startup sequence.
-   
-   You can also compile with profiling to see what functions are taking
-   execution time. The backend profile files will be deposited in the
-   pgsql/data directory. The client profile file will be put in the
-   client's current directory. Linux requires a compile with
-   -DLINUX_PROFILE for proper profiling.
+  http://wiki.postgresql.org/wiki/Development_information