projects / postgresql.git / commitdiff
| author | Bruce Momjian | |
| Wed, 1 Dec 2004 17:21:58 +0000 (17:21 +0000) | ||
| committer | Bruce Momjian | |
| Wed, 1 Dec 2004 17:21:58 +0000 (17:21 +0000) |
| doc/FAQ_DEV | patch | blob | blame | history | |
| doc/src/FAQ/FAQ_DEV.html | patch | blob | blame | history |
Last updated: Wed Dec 1 16:11:11 EST 2006
Current maintainer: Bruce Momjian ( The most recent version of this document can be viewed at Download the code and have a look around. See Subscribe to and read the PostgreSQL is developed mostly in the C programming language. It The source code is targeted at most of the popular Unix Most developers make use of the open source development tool Developers using this tool chain on Windows make use of MingW Some developers use compilers from other software vendors with Developers who are regularly rebuilding the source often pass You can learn more about these features by consulting the Send an email to pgsql-hackers with a proposal for what you want Other than documentation in the source tree itself, you can find Generate the patch in contextual diff format. If you are Ensure that your patch is generated against the most recent Finally, submit the patch to [email protected]. It There are several ways to obtain the source tree. Occasional Last updated: Sat Nov 27 01:02:35 EST 2004 Current maintainer: Bruce Momjian ( The most recent version of this document can be viewed at This was written by Lamar Owen: 2001-06-22 Read HACKERS for six months (or a full release cycle, whichever The TODO list. You've made the first step, by finding and subscribing to Discussion on the patch typically happens here. If the patch Once your contributions get accepted, things move from there. I make these statements from having watched the process for over To see a good example of how one goes about this, search the The source code is over 350,000 lines. Many fixes/features Another thing to keep in mind is that many fixes and features When adding code, keep in mind that it should use the existing The usual process for source additions is: There are several ways to obtain the source tree. Occasional To update the source tree, there are two ways. You can generate For hard-core developers, Marc([email protected]) will give First, use psql to make sure it is working as you expect. Aside from the User documentation mentioned in the regular FAQ, Regular developers may want to take advantage of anonymous Basic system testing The easiest way to test your code is to ensure that it builds It is worth advised that you pass --enable-cassert to Then, perform run time testing via psql. Regression test suite The next step is to test your changes against the existing If you've deliberately changed existing behaviour, this change Other run time testing Some developers make use of tools such as valgrind ( What about unit testing, static analysis, model There have been a number of discussions about other testing First, all the files in the src/tools directory are Second, you really should have an editor that can handle tags, Third, you need to get id-utils from: make_diff has tools to create patch diff files that can Our standard format is to indent each code level with one tab, In src/include/catalog: Second, you really should have an editor that can handle tags, Third, you need to get id-utils from By running tools/make_mkid, an archive of source symbols Some developers make use of cscope, which can be found at tools/make_diff has tools to create patch diff files that Our standard format is to indent each code level with one tab, pgindent is run on all source files just before each beta pginclude contains scripts used to add needed When adding system types, you will need to assign oids to them. I have four good books, An Introduction to Database There is also a database performance site, with a handbook The files configure and configure.in are part of When configure is run by the user, it tests various OS When you need to edit files, make sure you don't waste time There are a variety of places that need to be modified to add a Then, check src/include/port and add your new OS file, There is always a temptation to use the newest operating system First, we support 15+ operating systems, so any new feature has As an example, threads are not currently used in the backend code So, we are not ignorant of new features. It is just that This was written by Lamar Owen: 2001-05-03 As to how the RPMs are built -- to answer that question sanely I then download and build on as many different canonical I test the build by installing the resulting packages and You'll notice I said 'canonical' distributions above. That For a time I built on Mandrake for RedHat consumption -- no I _do_ attempt to make the _source_ RPM compatible with as many And, while I understand people's desire to immediately upgrade I am working towards a more open RPM distribution -- I would As to why all these files aren't part of the source tree, well, Of course, there are many projects that DO include all the files This was written by Tom Lane: 2001-05-07 If you just do basic "cvs checkout", "cvs update", "cvs commit", The first thing you have to know is the branch name for the pgindent is run on all source files just before each beta pginclude contains scripts used to add needed When adding system types, you will need to assign oids to them. I have four good books, An Introduction to Database There is also a database performance site, with a handbook The files configure and configure.in are part of When configure is run by the user, it tests various OS When you need to edit files, make sure you don't waste time There are a variety of places that need to be modified to add a Then, check src/include/port and add your new OS file, There is always a temptation to use the newest operating system First, we support 15+ operating systems, so any new feature has As an example, threads are not currently used in the backend So, we are not ignorant of new features. It is just that we are This was written by Lamar Owen: 2001-05-03 As to how the RPMs are built -- to answer that question sanely I then download and build on as many different canonical I test the build by installing the resulting packages and You'll notice I said 'canonical' distributions above. That For a time I built on Mandrake for RedHat consumption -- no I _do_ attempt to make the _source_ RPM compatible with as many And, while I understand people's desire to immediately upgrade I am working towards a more open RPM distribution -- I would As to why all these files aren't part of the source tree, well, Of course, there are many projects that DO include all the files This was written by Tom Lane: 2001-05-07 If you just do basic "cvs checkout", "cvs update", "cvs commit", The first thing you have to know is the branch name for the OK, so how do you do work on a branch? By far the best way is to Normally, to checkout the head branch, you just cd to the place OK, so how do you do work on a branch? By far the best way is to Normally, to checkout the head branch, you just cd to the place To get a past branch, you cd to whereever you want it and To get a past branch, you cd to whereever you want it and For example, just a couple days ago I did For example, just a couple days ago I did and now I have a maintenance copy of 7.1.*. When you've done a checkout in this way, the branch name is So, if you have a patch that needs to apply to both the head and There are three versions of the SQL standard: SQL-92, SQL:1999, Some SQL standards web pages are: PostgreSQL website development is discussed on the You first need to find the tuples(rows) you are interested in. The rows returned are cache-owned versions of the heap rows. If you can't use the system cache, you will need to retrieve the Open the table with heap_open(). You can then start a You can also use heap_fetch() to fetch rows by block Once you have the row, you can get data that is common to all Table, column, type, function, and view names are stored in and now I have a maintenance copy of 7.1.*. When you've done a checkout in this way, the branch name is So, if you have a patch that needs to apply to both the head and There are three versions of the SQL standard: SQL-92, SQL:1999, Some SQL standards web pages are: Many technical questions held by those new to the code have been If you cannot find discussion or your particular question, feel Major contributors also answer technical questions, including PostgreSQL website development is discussed on the You first need to find the tuples(rows) you are interested in. The rows returned are cache-owned versions of the heap rows. If you can't use the system cache, you will need to retrieve the Open the table with heap_open(). You can then start a You can also use heap_fetch() to fetch rows by block Once you have the row, you can get data that is common to all Table, column, type, function, and view names are stored in Many functions are called with both types of names, ie. We do this because this allows a consistent way to pass data Here are some of the List manipulation commands: Many functions are called with both types of names, ie. We do this because this allows a consistent way to pass data Here are some of the List manipulation commands: The structures passing around from the parser, rewrite, palloc() and pfree() are used in place of malloc() ereport() is used to send messages to the front-end, and ereport(ERROR) frees most memory and open file descriptors so Normally, transactions can not see the rows they modify. This However, there are cases where a transactions needs to see rows The structures passing around from the parser, rewrite, palloc() and pfree() are used in place of malloc() ereport() is used to send messages to the front-end, and ereport(ERROR) frees most memory and open file Normally, transactions can not see the rows they modify. This However, there are cases where a transactions needs to see rows+
+
++href=
+"http://www.PostgreSQL.org/docs/faqs/FAQ_DEV.html">http://www.PostgreSQL.org/docs/faqs/FAQ_DEV.html.
+
+
+
+
+
+
General Questions
+
+
+
+development?
+
+to develop code?
+
+
+work on?
+
+
+
+source tree?
+
+
+developers?
+
+
+
+
+devices/async-I/O, <insert your favorite wizz-bang feature
+here>?
+
+
+
+standards?
+
+assistance?
+
+site development?
+
+
+
Technical Questions
+
+
+
+tables from the backend code?
+
+view names sometimes referenced as Name or NameData,
+and sometimes as char *?
+
+to make data structures?
+
+else should I do?
+
+pfree() to allocate memory?
+
+
+
+
+
+
+
General Questions
+
+
+
+development?
+
++"#1.7">1.7.
+
++"http://archives.posrgresql.org/pgsql-hackers">pgsql-hackers
+mailing list (often termed 'hackers'). This is where the major
+contributors and core members of the project discuss
+development.
+
+
+to develop code?
+
+
+also makes use of Yacc and Lex.
+
+
+platforms and the Windows environment (XP, Windows 2000, and
+up).
+
+
+chain. If you have contributed to open source software before, you
+will probably be familiar with these tools. They include: GCC (+href="http://gcc.gnu.org">http://gcc.gnu.org, GDB (+"http://www.gnu.org/software/gdb/gdb.html">www.gnu.org/software/gdb/gdb.html),
+autoconf (+"http://www.gnu.org/software/autoconf/">www.gnu.org/software/autoconf/)
+AND GNU make (+"http://www.gnu.org/software/make/make.html">www.gnu.org/software/make/make.html.
+
+
+(see +"http://www.mingw.org/">http://www.mingw.org/).
+
+
+mixed results.
+
+
+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.
+
+
+
+Outstanding features are detailed in the TODO list. This is located
+in doc/TODO in the source distribution or at +"http://developer.postgresql.org/todo.php">http://developer.postgresql.org/todo.php.
+
+
+archives, the SQL standards and the recommend texts (see +"#1.10">1.10).
+
+
+work on?
+
+
+to do (assuming your contribution is not trivial). Working in
+isolation is not advisable: others may be working on the same TODO
+item; you may have misunderstood the TODO item; your approach may
+benefit from the review of others.
+
+
+code?
+
+
+some papers/presentations discussing the code at +"http://developers.postgresql.org">http://developers.postgresql.org.
+
+
+
+
+unfamiliar with this, you may find the script
+src/tools/makediff/difforig useful.
+
+
+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">1.15).
+
+
+will be reviewed by other contributors to the project and may be
+either accepted or sent back for further work.
+
+
+source tree?
+
+
+developers can just get the most recent source tree snapshot from
++"ftp://ftp.postgresql.org">ftp://ftp.postgresql.org.
-
-
-
-
-
-
-
- - alink="#0000FF">
-
Developer's Frequently Asked Questions (FAQ) for
- PostgreSQL
-
-
-
- -
-
- - "http://www.PostgreSQL.org/docs/faqs/FAQ_DEV.html">http://www.PostgreSQL.org/docs/faqs/FAQ_DEV.html.
-
-
-
-
-
-
-
General Questions
-
-
- development?
-
-
- tree?
-
-
-
-
-
-
- devices/async-I/O, <insert your favorite wizz-bang feature
- here>?
-
-
-
- standards?
-
- web site development?
-
-
-
Technical Questions
-
-
- tables from the backend code?
-
- names sometimes referenced as Name or NameData, and
- sometimes as char *?
-
- make data structures?
-
- should I do?
-
- pfree() to allocate memory?
-
-
-
-
-
-
-
-
General Questions
-
-
-
- development?
-
-
-
-
-
- What open source development process is used by the PostgreSQL
- team?
-
-
- is longer). Really. HACKERS _is_the process. The process is not
- well documented (AFAIK -- it may be somewhere that I am not aware
- of) -- and it changes continually.
-
- What development environment (OS, system, compilers, etc) is
- required to develop code?
-
-
- website has links to this information. The distribution tarball
- itself includes all the extra tools and documents that go beyond a
- good Unix-like development environment. In general, a modern unix
- with a modern gcc, GNU make or equivalent, autoconf (of a
- particular version), and good working knowledge of those tools are
- required.
-
- What areas need support?
-
-
-
-
- HACKERS. Once you find an area to look at in the TODO, and have
- read the documentation on the internals, etc, then you check out a
- current CVS,write what you are going to write (keeping your CVS
- checkout up to date in the process), and make up a patch (as a
- context diff only) and send to the PATCHES list, prefereably.
-
-
- adds a major feature, it would be a good idea to talk about it
- first on the HACKERS list, in order to increase the chances of it
- being accepted, as well as toavoid duplication of effort. Note that
- experienced developers with a proven track record usually get the
- big jobs -- for more than one reason. Also note that PostgreSQL is
- highly portable -- nonportable code will likely be dismissed out of
- hand.
-
-
- Typically, you would be added as a developer on the list on the
- website when one of the other developers recommends it. Membership
- on the steering committee is by invitation only, by the other
- steering committee members, from what I have gathered watching
- froma distance.
-
-
- two years.
-
-
- archives for the name 'Tom Lane' and see what his first post
- consisted of, and where he took things. In particular, note that
- this hasn't been _that_ long ago -- and his bugfixing and general
- deep knowledge with this codebase is legendary. Take a few days to
- read after him. And pay special attention to both the sheer
- quantity as well as the painstaking quality of his work. Both are
- in high demand.
-
-
-
-
- are isolated to one specific area of the code. Others require
- knowledge of much of the source. If you are confused about where to
- start, ask the hackers list, and they will be glad to assess the
- complexity and give pointers on where to start.
-
-
- can be added with surprisingly little code. I often start by adding
- code, then looking at other areas in the code where similar things
- are done, and by the time I am finished, the patch is quite small
- and compact.
-
-
- facilities in the source, for performance reasons and for
- simplicity. Often a review of existing code doing similar things is
- helpful.
-
-
-
-
-
-
-
-
-
-
-
-
- tree?
-
-
- developers can just get the most recent source tree snapshot from
- ftp.postgresql.org. For regular developers, you can use CVS. CVS
- allows you to download the source tree, then occasionally update
- your copy of the source tree with any new changes. Using CVS, you
- don't have to download the entire source each time, only the
- changed files. Anonymous CVS does not allows developers to update
- the remote source tree, though privileged developers can do this.
- There is a CVS section (http://developer.postgresql.org/docs/postgres/cvs.html)
- in our documentation that describes how to use remote CVS. You can
- also use CVSup, which has similarly functionality, and is available
- from ftp.postgresql.org.
-
-
- a patch against your current source tree, perhaps using the
- make_diff tools mentioned above, and send them to the patches list.
- They will be reviewed, and applied in a timely manner. If the patch
- is major, and we are in beta testing, the developers may wait for
- the final release before applying your patches.
-
-
- you a Unix shell account on postgresql.org, so you can use CVS to
- update the main source tree, or you can ftp your files into your
- account, patch, and cvs install the changes directly into the
- source tree.
-
-
-
-
- Then run src/test/regress and get the output of
- src/test/regress/checkresults with and without your changes,
- to see that your patch does not change the regression test in
- unexpected ways. This practice has saved me many times. The
- regression tests test the code in ways I would never do, and has
- caught many bugs in my patches. By finding the problems now, you
- save yourself a lot of debugging later when things are broken, and
- you can't figure out when it happened.
-
-
- developers?
-
-
- there are several development tools available. First, all the files
- in the /tools directory are designed for developers.
-
+
+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">http://developer.postgresql.org/docs/postgres/cvs.html.
+
+
+
+
+
+
+against the latest verion of the code and that it does not generate
+compiler warnings.
+
+
+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.
+
+
+
+
+
+
+regression test suite. To do this, issue "make check" in the root
+directory of the source tree. If any tests failure,
+investigate.
+
+
+may cause a regression test failure but not any actual regression.
+If so, you should also patch the regression test suite.
+
+
+
++"http://valgrind.kde.org">http://valgrind.kde.org) for memory
+testing, gprof (which comes with the GNU binutils suite) and
+oprofile (+"http://oprofile.sourceforge.net/">http://oprofile.sourceforge.net/)
+for profiling and other related tools.
+
+
+checking...?
+
+
+frameworks and some developers are exploring these ideas.
+
+
+developers?
+
+
+designed for developers.
+
+
RELEASE_CHANGES changes we have to make for each release
- SQL_keywords standard SQL'92 keywords
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
- mkldexport create AIX exports file
- pgindent indents C source files
- pgjindent indents Java source files
+ pgcvslog used to generate a list of changes for each release
pginclude scripts for adding/removing include files
- unused_oids in pgsql/src/include/catalog
-
- Let me note some of these. If you point your browser at the
- file:/usr/local/src/pgsql/src/tools/backend/index.html
- directory, 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.
-
-
- 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.
-
-
-
- -"ftp://alpha.gnu.org/gnu/id-utils-3.2d.tar.gz">ftp://alpha.gnu.org/gnu/id-utils-3.2d.tar.gz
- -"ftp://tug.org/gnu/id-utils-3.2d.tar.gz">ftp://tug.org/gnu/id-utils-3.2d.tar.gz
- -"ftp://ftp.enst.fr/pub/gnu/gnits/id-utils-3.2d.tar.gz">ftp://ftp.enst.fr/pub/gnu/gnits/id-utils-3.2d.tar.gz
-
- By running tools/make_mkid, an archive of source symbols can
- be created that can be rapidly queried like grep or edited.
- Others prefer glimpse.
-
-
- be applied to the distribution. This produces context diffs, which
- is our preferred format.
-
-
- where each tab is four spaces. You will need to set your editor to
- display tabs as four spaces:
-
-
+ pgindent indents source files
+ pgtest a semi-automated build system
+ thread a thread testing script
+
+
+
+
+
+ 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.
+
+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.
+
++"ftp://ftp.gnu.org/gnu/id-utils/">ftp://ftp.gnu.org/gnu/id-utils/
+
+
+can be created that can be rapidly queried.
+
++href="http://cscope.sf.net">http://cscope.sf.net/. Others use
+glimpse, which can be found at +"http://webglimpse.net/">http://webglimpse.net/.
+
+
+can be applied to the distribution. This produces context diffs,
+which is our preferred format.
+
+
+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
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")
- )
+ (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))
+ (setq auto-mode-alist
+ (cons '("\\`/home/andrew/pgsql/.*\\.[chyl]\\'" . pgsql-c-mode)
+ auto-mode-alist))
or
/*
* Local variables:
* 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 constent coding style.
-
-
- 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.
-
-
-
#include's to include files, and removed unneeded-
#include's.-
-
- There is also a script called unused_oids in
- pgsql/src/include/catalog that shows the unused oids.
-
-
-
-
- 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
-
-
- on-line written by Jim Gray at - "http://www.benchmarkresources.com">http://www.benchmarkresources.com.
-
-
-
-
- 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.
-
-
- 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.
-
-
- 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.
-
-
-
-
- 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.
-
-
- 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.
-
-
- devices/async-I/O, <insert your favorite wizz-bang feature
- here>?
-
-
- features as soon as they arrive. We resist that temptation.
-
-
- 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.
-
-
- because:
-
-
-
-
-
-
-
- remaining backend startup time.
-
-
-
-
-
- we are cautious about their adoption. The TODO list often
- contains links to discussions showing our reasoning in
- these areas.
-
-
-
-
-
-
-
-
- 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:
-
-
-
- 'behave' in the different environment of the RPMset;
-
-
-
-
-
-
- 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);
-
-
- trivial undertaking in a package of this size.
-
-
-
- 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.
-
-
- 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.
-
-
- 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.
-
-
- 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!
- :-)
-
-
- 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.
-
-
- 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.
-
-
- 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.
-
-
- 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.
-
-
- necessary to build RPMs from their Official Tarball (TM).
-
-
-
-
-
-
-
-
- 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.
-
-
- 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:
-
+
+
+
+ pgindent will the format code by specifying flags to your
+operating system's utility indent. This +"http://ezine.daemonnews.org/200112/single_coding_style.html">article
+describes the value of a consistent coding style.
+
+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.
+
+
+
#include's to include files, and removed unneeded+
#include's.+
+
+There is also a script called unused_oids in
+pgsql/src/include/catalog that shows the unused oids.
+
+
+developers?
+
+
+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
+
+
+on-line written by Jim Gray at +"http://www.benchmarkresources.com">http://www.benchmarkresources.com..
+
+
+
+
+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.
+
+
+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.
+
+
+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.
+
+
+
+
+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.
+
+
+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.
+
+
+devices/async-I/O, <insert your favorite wizz-bang feature
+here>?
+
+
+features as soon as they arrive. We resist that temptation.
+
+
+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.
+
+
+code because:
+
+
+
+
+
+
+
+remaining backend startup time.
+
+
+
+
+
+cautious about their adoption. The TODO list often contains links
+to discussions showing our reasoning in these areas.
+
+
+
+
+
+
+
+
+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:
+
+
+
+'behave' in the different environment of the RPMset;
+
+
+
+
+
+
+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);
+
+
+trivial undertaking in a package of this size.
+
+
+
+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.
+
+
+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.
+
+
+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.
+
+
+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!
+:-)
+
+
+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.
+
+
+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.
+
+
+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.
+
+
+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.
+
+
+necessary to build RPMs from their Official Tarball (TM).
+
+
+
+
+
+
+
+
+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.
+
+
+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
-
-
-
- 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.)
-
-
- you want to contain the toplevel "pgsql" directory and say
-
+
+
+
+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.)
+
+
+you want to contain the toplevel "pgsql" directory and say
+
+
cvs ... checkout pgsql
-
+
+
+
+say
-
- say
-
+
cvs ... checkout -r BRANCHNAME pgsql
-
+
+
+
-
-
+
mkdir ~postgres/REL7_1
cd ~postgres/REL7_1
cvs ... checkout -r REL7_1_STABLE pgsql
-
-
-
-
-
- "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.
-
-
- 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.
-
-
- standards?
-
-
- and SQL:2003. They are endorsed by ANSI and ISO. Draft versions
- can be downloaded from:
-
- - href="http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt">
- http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt
- - href="http://www.cse.iitb.ac.in/dbms/Data/Papers-Other/SQL1999/ansi-iso-9075-2-1999.pdf">
- http://www.cse.iitb.ac.in/dbms/Data/Papers-Other/SQL1999/ansi-iso-9075-2-1999.pdf
- - href="http://www.wiscorp.com/sql/sql_2003_standard.zip">
- http://www.wiscorp.com/sql/sql_2003_standard.zip
-
-
-
-
- - href="http://troels.arvin.dk/db/rdbms/links/#standards">
- http://troels.arvin.dk/db/rdbms/links/#standards
- - href="http://www.wiscorp.com/SQLStandards.html">
- http://www.wiscorp.com/SQLStandards.html
- - href="http://www.contrib.andrew.cmu.edu/~shadow/sql.html#syntax">
- http://www.contrib.andrew.cmu.edu/~shadow/sql.html#syntax (SQL-92)
- - href="http://dbs.uni-leipzig.de/en/lokal/standards.pdf">
- http://dbs.uni-leipzig.de/en/lokal/standards.pdf (paper)
-
-
-
- web site development?
-
-
- [email protected] mailing list. The is a project page where
- the source code is available at - href="http://gborg.postgresql.org/project/pgweb/projdisplay.php">http://gborg.postgresql.org/project/pgweb/projdisplay.php
- , the code for the next version of the website is under the "portal"
- module. You will al so 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 - href="http://xzilla.postgresql.org/todo">http://xzilla.postgresql.org/todo
-
-
-
-
Technical Questions
-
-
-
- tables from the backend code?
-
-
- 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.
-
-
- 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.
-
-
- 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.
-
-
- 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.
-
-
- 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.
-
-
- 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 may 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.
-
-
- names sometimes referenced as Name or NameData, and
- sometimes as char *?
-
-
- 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+
+
+
+
+
+"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.
+
+
+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.
+
+
+standards?
+
+
+and SQL:2003. They are endorsed by ANSI and ISO. Draft versions can
+be downloaded from:
+
+
++"http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt">http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt
+
++"http://www.cse.iitb.ac.in/dbms/Data/Papers-Other/SQL1999/ansi-iso-9075-2-1999.pdf">
+http://www.cse.iitb.ac.in/dbms/Data/Papers-Other/SQL1999/ansi-iso-9075-2-1999.pdf
+
++"http://www.wiscorp.com/sql/sql_2003_standard.zip">http://www.wiscorp.com/sql/sql_2003_standard.zip
+
+
+
+
+
++"http://troels.arvin.dk/db/rdbms/links/#standards">http://troels.arvin.dk/db/rdbms/links/#standards
+
++"http://www.wiscorp.com/SQLStandards.html">http://www.wiscorp.com/SQLStandards.html
+
++"http://www.contrib.andrew.cmu.edu/~shadow/sql.html#syntax">http://www.contrib.andrew.cmu.edu/~shadow/sql.html#syntax
+(SQL-92)
+
++"http://dbs.uni-leipzig.de/en/lokal/standards.pdf">http://dbs.uni-leipzig.de/en/lokal/standards.pdf
+(paper)
+
+
+
+assistance?
+
+
+answered on the pgsql-hackers mailing list - the archives of which
+can be found at +"http://archives.postgresql.org/pgsql-hackers/">http://archives.postgresql.org/pgsql-hackers/.
+
+
+free to put it to the list.
+
+
+questions about development of new features, on IRC at
+irc.freenode.net in the #postgresql channel.
+
+
+web site development?
+
+
[email protected] mailing list. The is a project page where
+the source code is available at +"http://gborg.postgresql.org/project/pgweb/projdisplay.php">http://gborg.postgresql.org/project/pgweb/projdisplay.php
+, the code for the next version of the website is under the
+"portal" module. You will al so 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 +href=
+"http://xzilla.postgresql.org/todo">http://xzilla.postgresql.org/todo
+
+
+
Technical Questions
+
+
+
+in tables from the backend code?
+
+
+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.
+
+
+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.
+
+
+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.
+
+
+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.
+
+
+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.
+
+
+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 may 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.
+
+view names sometimes referenced as Name or NameData,
+and sometimes as char *?
+
+
+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.
-
-
- 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.
-
-
- make data structures?
-
-
- 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.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
- 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 *i, *list;+
+
+
+Table, column, type, function, and view names that come into the
+backend via user queries are stored as variable-length,
+null-terminated character strings.
+
+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.
+
+
+List to make data structures?
+
+
+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.
+
+
+
+
+
+
+
+
+element i.
+
+
+
+
+
+
+
+
+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)
{
/* process var here */
}
-CODE>
-PRE>
- >
+code>
+pre>
+>
-
+
-
- new list with node if list is NIL.>
+
+list with node if list is NIL.>
-
+
-
- expensive that lcons.>
+
+expensive that lcons.>
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
- 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)+
+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.
-
-
- else should I do?
-
-
- 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. Make sure you
- add support for your new field to these files. Find any other
- places the structure may need code for your new field. mkid
- is helpful with this (see above).
-
-
- pfree() to allocate memory?
-
-
- 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.
-
-
-
-
- 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.
-
-
- you don't need to clean these up before the call.
-
-
-
-
- allows
UPDATE foo SET x = x + 1 to work correctly.-
-
- 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.
-
-
-
+
+
+
+The output appears in the postmaster log file, or on your screen if
+you are running a backend directly without a postmaster.
+
+What else should I do?
+
+
+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 may need code for your new field. mkid
+is helpful with this (see
+
+
+pfree() to allocate memory?
+
+
+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.
+
+
+
+
+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.
+
+
+descriptors so you don't need to clean these up before the
+call.
+
+
+
+
+allows
UPDATE foo SET x = x + 1 to work correctly.+
+
+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.
+