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.
-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.
- -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.
- -You can learn more about these features by consulting the - archives, the SQL standards and the recommend texts (see 1.10).
- -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.
- -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.
- -Other than documentation in the source tree itself, you can find - some papers/presentations discussing the code at - http://www.postgresql.org/developer.
- -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.
- -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.
- -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 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.
- -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..
- -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.
- -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.
- -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:
- -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.
- -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:
- -The developer FAQ can be found on the PostgreSQL wiki:
-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).
- -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.
- -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:
- -Some SQL standards web pages are:
- -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.
- -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
- -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.
-
- 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.
- -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:
- --- You can print nodes easily inside gdb. First, to disable - output truncation when you use the gdb print command: --
-- 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.
-
-(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.
-
- 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).
- -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.
- -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.
- -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.
- -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.
+ - -- cgit v1.2.3