diff --git a/HISTORY b/HISTORY index 0be1f489d1..f6d06df191 100644 --- a/HISTORY +++ b/HISTORY @@ -7,9 +7,6 @@ previous releases of PostgreSQL. * The migration/6.2.1_to_6.3 file contains a detailed description * of the feature changes in this release, and is recommended reading. -CHANGES IN THE 6.3 RELEASE --------------------------- - Bug Fixes --------- Fix binary cursors broken by MOVE implementation(Vadim) @@ -43,6 +40,8 @@ Allow multiple-argument functions in constraint clauses(Thomas) Check boolean input literals for 'true','false','yes','no','1','0' and throw elog(ERROR) if unrecognized(Thomas) Major large objects fix +Fix for GROUP BY showing duplicates(Vadim) +Fix for index scans in MergeJion(Vadim) Enhancements ------------ diff --git a/doc/FAQ b/doc/FAQ index c51c676f3e..14b9c03628 100644 --- a/doc/FAQ +++ b/doc/FAQ @@ -1,717 +1,597 @@ - -
--Last updated: Wed Feb 25 14:37:07 EST 1998 -
-Current maintainer: Bruce Momjian (maillist@candle.pha.pa.us)
-
-The most recent version of this document can be viewed at -the postgreSQL Web site, http://postgreSQL.org. -
-Linux-specific questions are answered in -http://postgreSQL.org/docs -/faq-linux.shtml. -
-Irix-specific questions are answered in -http://postgreSQL.org/docs/ -faq-irix.shtml. -
-
-
+ Frequently Asked Questions (FAQ) for PostgreSQL + + Last updated: Sat Feb 28 10:04:28 EST 1998 + + Current maintainer: Bruce Momjian (maillist@candle.pha.pa.us) + + The most recent version of this document can be viewed at the + postgreSQL Web site, http://postgreSQL.org. + + Linux-specific questions are answered in + http://postgreSQL.org/docs/faq-linux.shtml. + + Irix-specific questions are answered in + http://postgreSQL.org/docs/faq-irix.shtml. + _________________________________________________________________ + +Questions answered: + + 1) General questions + + 1.1) What is PostgreSQL? + 1.2) What does PostgreSQL run on? + 1.3) Where can I get PostgreSQL? + 1.4) What's the copyright on PostgreSQL? + 1.5) Support for PostgreSQL + 1.6) Latest release of PostgreSQL + 1.7) Is there a commercial version of PostgreSQL? + 1.8) What documentation is available for PostgreSQL? + 1.9) What version of SQL does PostgreSQL use? + 1.10) Does PostgreSQL work with databases from earlier versions of + postgres? + 1.11) Are there ODBC drivers for PostgreSQL? + 1.12) What tools are available for hooking postgres to Web pages? + 1.13) Does PostgreSQL have a graphical user interface? A report + generator? A embedded query language interface? + 1.14) What is a good book to learn SQL? + + 2) Installation/Configuration questions + + 2.1) initdb doesn't run + 2.2) when I start up the postmaster, I get "FindBackend: could not + find a backend to execute..." "postmaster: could not find backend to + execute..." + 2.3) The system seems to be confused about commas, decimal points, and + date formats. + 2.4) How do I install PostgreSQL somewhere other than + /usr/local/pgsql? + 2.5) When I run postmaster, I get a Bad System Call core dumped + message. + 2.6) When I try to start the postmaster, I get IpcMemoryCreate errors. + 2.7) I have changed a source file, but a recompile does not see the + change? + 2.8) How do I prevent other hosts from accessing my PostgreSQL + 2.9) I can't access the database as the 'root' user. + 2.10) All my servers crash under concurrent table access. Why? + 2.11) How do I tune the database engine for better performance? + 2.12) What debugging features are available in PostgreSQL? + 2.13) How do I enable more than 32 concurrent backends? + + 3) Operational questions + + 3.1) Does PostgreSQL support nested subqueries? + 3.2) I've having a lot of problems using rules. + 3.3) I can't seem to write into the middle of large objects reliably. + 3.4) How can I write client applications to PostgreSQL? + 3.5) How do I set up a pg_group? + 3.6) What is the exact difference between binary cursors and normal + cursors? + 3.7) What is a R-tree index and what is it used for? + 3.8) What is the maximum size for a tuple? + 3.9) I defined indices but my queries don't seem to make use of them. + Why? + 3.10) How do I do regular expression searches? case-insensitive regexp + searching? + 3.11) I experienced a server crash during a vacuum. How do I remove + the lock file? + 3.12) What is the difference between the various character types? + 3.13) In a query, how do I detect if a field is NULL? + 3.14) How do I see how the query optimizer is evaluating my query? + 3.15) How do I create a serial field? + 3.16) What are the pg_psort.XXX files in my database directory? + 3.17) Why can't I connect to my database from another machine? + 3.18) How do I find out what indexes or operations are defined in the + database? + 3.19) What is the time-warp feature and how does it relate to vacuum? + 3.20) What is an oid? What is a tid? + 3.21) What is the meaning of some of the terms used in Postgres? + 3.22) What is Genetic Query Optimization? + 3.23) How do you remove a column from a table? + 3.24) How do SELECT only the first few rows of a query? + 3.25) Why can't I create a column named "time"? + 3.26) How much database disk space is required to store data from a + typical flat file? + + 4) Questions about extending PostgreSQL + + 4.1) I wrote a user-defined function and when I run it in psql, it + dumps core. + 4.2) I get messages of the type NOTICE:PortalHeapMemoryFree: + 0x402251d0 + 4.3) I've written some nifty new types and functions for PostgreSQL. + 4.4) How do I write a C function to return a tuple? + + 5) Bugs + + 5.1) How do I make a bug report? + _________________________________________________________________ + +Section 1: General Questions + + 1.1) What is PostgreSQL? + + PostgreSQL is an enhancement of the POSTGRES database management + system, a next-generation DBMS research prototype. While PostgreSQL + retains the powerful data model and rich data types of POSTGRES, it + replaces the PostQuel query language with an extended subset of SQL. + PostgreSQL is free and the complete source is available. + + PostgreSQL development is being performed by a team of Internet + developers who all subscribe to the PostgreSQL development mailing + list. The current coordinator is Marc G. Fournier + (scrappy@postgreSQL.org). (See below on how to join). This team is now + responsible for all current and future development of PostgreSQL. + + The authors of PostgreSQL 1.01 were Andrew Yu and Jolly Chen. Many + others have contributed to the porting, testing, debugging and + enhancement of the code. The original Postgres code, from which + PostgreSQL is derived, was the effort of many graduate students, + undergraduate students, and staff programmers working under the + direction of Professor Michael Stonebraker at the University of + California, Berkeley. + + The original name of the software at Berkeley was Postgres. When SQL + functionality was added in 1995, its name was changed to Postgres95. + The name was changed at the end of 1996 to PostgreSQL. + + 1.2) What does PostgreSQL run on? + + The authors have compiled and tested PostgreSQL on the following + platforms(some of these compiles require gcc 2.7.0): + * aix - IBM on AIX 3.2.5 or 4.x + * alpha - DEC Alpha AXP on Digital Unix 2.0, 3.2, 4.0 + * BSD44_derived - OSs derived from 4.4-lite BSD (NetBSD, FreeBSD) + * bsdi - BSD/OS 2.0, 2.01, 2.1, 3.0 + * dgux - DG/UX 5.4R4.11 + * hpux - HP PA-RISC on HP-UX 9.0, 10 + * i386_solaris - i386 Solaris + * irix5 - SGI MIPS on IRIX 5.3 + * linux - Intel x86 on Linux 2.0 and Linux ELF SPARC on Linux ELF + PPC on Linux Elf (For non-ELF Linux, see LINUX_ELF below). + * sco - SCO 3.2v5 + * sparc_solaris - SUN SPARC on Solaris 2.4, 2.5, 2.5.1 + * sunos4 - SUN SPARC on SunOS 4.1.3 + * svr4 - Intel x86 on Intel SVR4 and MIPS + * ultrix4 - DEC MIPS on Ultrix 4.4 + + The following platforms have known problems/bugs: + * nextstep - Motorola MC68K or Intel x86 on NeXTSTEP 3.2 + + 1.3) Where can I get PostgreSQL? + + The primary anonymous ftp site for PostgreSQL is: + * ftp://ftp.postgreSQL.org/pub + + A mirror site exists at: + * ftp://postgres95.vnet.net/pub/postgres95 + * ftp://ftp.luga.or.at/pub/postgres95 + * ftp://cal011111.student.utwente.nl/pub/postgres95 + * ftp://ftp.uni-trier.de/pub/database/rdbms/postgres/postgres95 + * ftp://rocker.sch.bme.hu + + 1.4) What's the copyright on PostgreSQL? + + PostgreSQL is subject to the following COPYRIGHT. + + PostgreSQL Data Base Management System + + Copyright (c) 1994-6 Regents of the University of California + + Permission to use, copy, modify, and distribute this software and its + documentation for any purpose, without fee, and without a written + agreement is hereby granted, provided that the above copyright notice + and this paragraph and the following two paragraphs appear in all + copies. + + IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY + FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, + INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND + ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN + ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + + THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, + INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE + PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF + CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, + UPDATES, ENHANCEMENTS, OR MODIFICATIONS. + + 1.5) Support for PostgreSQL + + There is no official support for PostgreSQL from the original + maintainers or from University of California, Berkeley. It is + maintained through volunteer effort only. + + The main mailing list is: questions@postgreSQL.org. It is available + for discussion o f matters pertaining to PostgreSQL, including but not + limited to bug reports and fixes. For info on how to subscribe, send a + mail with the lines in the body (not the subject line) + -
-PostgreSQL is an enhancement of the POSTGRES database management system, -a next-generation DBMS research prototype. While PostgreSQL retains the -powerful data model and rich data types of POSTGRES, it replaces the -PostQuel query language with an extended subset of SQL. PostgreSQL is -free and the complete source is available. -
-PostgreSQL development is being performed by a team of Internet -developers who all subscribe to the PostgreSQL development mailing list. -The current coordinator is Marc G. Fournier (scrappy@postgreSQL.org). (See -below on how to join). This team is now responsible for all current and -future development of PostgreSQL. -
-The authors of PostgreSQL 1.01 were Andrew Yu and Jolly Chen. Many -others have contributed to the porting, testing, debugging and -enhancement of the code. The original Postgres code, from which -PostgreSQL is derived, was the effort of many graduate students, -undergraduate students, and staff programmers working under the -direction of Professor Michael Stonebraker at the University of -California, Berkeley. -
-The original name of the software at Berkeley was Postgres. When SQL -functionality was added in 1995, its name was changed to Postgres95. The -name was changed at the end of 1996 to PostgreSQL. -
-
-The authors have compiled and tested PostgreSQL on the following -platforms(some of these compiles require gcc 2.7.0): -
-
The primary anonymous ftp site for PostgreSQL is: -
-A mirror site exists at: -
-PostgreSQL is subject to the following COPYRIGHT. -
-PostgreSQL Data Base Management System -
-Copyright (c) 1994-6 Regents of the University of California -
-Permission to use, copy, modify, and distribute this software and its -documentation for any purpose, without fee, and without a written -agreement is hereby granted, provided that the above copyright notice -and this paragraph and the following two paragraphs appear in all -copies. -
-IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY -FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, -INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS -DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF -THE POSSIBILITY OF SUCH DAMAGE. -
-THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, -INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY -AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER -IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO -OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR -MODIFICATIONS. -
-
-There is no official support for PostgreSQL from the original -maintainers or from University of California, Berkeley. It is -maintained through volunteer effort only. -
-The main mailing list is: questions@postgreSQL.org. It -is available for discussion o f matters pertaining to PostgreSQL, -including but not limited to bug reports and fixes. For info on how to -subscribe, send a mail with the lines in the body (not the subject line) -
-
subscribe
end
-
-
--to questions-request@postgreSQL.org -. -
-There is also a digest list available. To subscribe to this list, send -email to: - -questions-digest-request@postgreSQL.org with a BODY of: -
- - subscribe - end - --Digests are sent out to members of this list whenever the main list has -received around 30k of messages. -
-There is a bugs mailing list available. To subscribe to this -list, send email to bugs-request@postgreSQL.org -with a BODY of: -
-There is also a developers discussion mailing list available. To subscribe to -this -list, send email to hackers-request@postgreSQL.org -with a BODY of: -
-
- - subscribe - end - --
-Additional information about PostgreSQL can be found via the PostgreSQL -WWW home page at: -
- http://postgreSQL.org --
-
-The latest release of PostgreSQL is version 6.2.1, which was released on -October 17th, 1997. We are testing 6.3 beta. For information about -what is new in 6.3, see our TODO list on our WWW page. -
-We plan to have major releases every three months. -
-
-Illustra Information Technology (a wholly owned subsidiary of Informix -Software, Inc.) sells an object-relational DBMS called Illustra that was -originally based on postgres. Illustra has cosmetic similarities to -PostgreSQL but has more features, is more robust, performs better, and -offers real documentation and support. On the flip side, it costs -money. For more information, contact sales@illustra.com -
-
-A user manual, manual pages, and some small test examples are included -in the distribution. The sql and built-in manual pages are particularly -important. -
-The www page contains pointers to an implementation guide and five -papers written about postgres design concepts and features. -
-
-PostgreSQL supports a subset of SQL-92. It has most of the important -constructs but lacks some of the functionality. The most visible -differences are: -
-On the other hand, you get to create user-defined types, functions, -inheritance etc. -
-
-PostgreSQL v1.09 is compatible with databases created with v1.01. -
-Upgrading to 6.3 from earlier releases requires a dump and restore. -
-Upgrading to 6.2.1 from pre-6.2 requires a dump and restore. -
-Upgrading to 6.2.1 from 6.2 does not require a dump, but see the -appropriate /migration file in the distribution. -
-Those ugrading from versions earlier than 1.09 must upgrade to 1.09 -first without a dump/reload, then dump the data from 1.09, and then load -it into 6.2.1 or 6.3 beta. -
-
-There are two ODBC drivers available, PostODBC and OpenLink ODBC. -
-PostODBC is included in the distribution. -For all people being interested in PostODBC, there are now two mailing -lists devoted to the discussion of PostODBC. The mailing lists are: -
--these lists are ordinary majordomo mailing lists. You can subscribe by -sending a mail to: -
--OpenLink ODBC is very popular. You can get it from -http://www.openlinksw.com/postgres.html. It works with our standard -ODBC client software so you'll have Postgres ODBC available on every -client platform we support (Win, Mac, Unix, VMS). -
-We will probably be selling this product to people who need -commercial-quality support, but a freeware version will always be -available. Questions to postgres95@openlink.co.uk. -
-
-A nice introduction to Database-backed Web pages can be seen at: -http://www.webtools.com -
-For web integration, PHP is an excellent interface. The URL for that -is http://www.php.net -
-PHP is great for simple stuff, but for more complex stuff, some still -use the perl interface and CGI.pm. -
-An WWW gatway based on WDB using perl can be downloaded from: -
--We have a nice graphical user interface called pgaccess, which is -shipped as part of the distribtion. Pgaccess also has a report -generator. -
-We also have ecpg, which is an embedded SQL query language interface for -C. This is also included. -
-
-Many of our users like The Practical SQL Handbook, -Bowman et al, Addison Wesley. -
-
-
-
-
-You probably do not have the right path set up. The 'postgres' -executable needs to be in your path. -
-
-Check your locale configuration. PostgreSQL uses the locale settings of -the user that ran the postmaster process. Set those accordingly for -your operating environment. -
-
-You need to edit Makefile.global and change POSTGRESDIR accordingly, or -create a Makefile.custom and define POSTGRESDIR there. -
-
-It could be a variety of problems, but first check to see that you have -system V extensions installed on your kernel. PostgreSQL requires kernel -support for shared memory. -
-
-You either do not have shared memory configured properly in kernel or -you need to enlarge the shared memory available in the kernel. The -exact amount you need depends on your architecture and how many buffers -you configure postmaster to run with. For most systems, with default -buffer sizes, you need a minimum of ~760K. -
-
-The Makefiles do not have the proper dependencies for include files. You -have to do a 'make clean' and then another 'make'. -
-
-By default, PostgreSQL only allows connections from the local machine -using unix domain. You must add the -i flag to the postmaster, and -enable host-based authentication by modifying the file $PGDATA/pg_hba -accordingly. -
-
-You should not create database users with user id 0(root). They will be -unable to access the database. This is a security precaution because -of the ability of any user to dynamically link object modules into the -database engine. -
-
-This problem can be caused by a kernel that is not configured to support -semaphores. -
-
-There are two things that can be done. You can disable fsync() by -starting the postmaster with a '-o -F' option. This -will prevent fsync()'s from flushing to disk after every transaction. -
-You can also use the postmaster -B option to increase the number of -shared memory buffers shared among the backend processes. If you make -this parameter too high, the process will not start or crash -unexpectedly. Each buffer is 8K and the defualt is 64 buffers. -
-You can also use the postgres -S option to increase the maximum -amount of memory used by each backend process for temporary sorts. -Each buffer is 1K and the defualt is 512 buffers. -
-
-PostgreSQL has several features that report status information that can -be valuable for debugging purposes. -
-First, by running configure with the -enable-cassert option, -many assert()'s monitor the progress of the backend and halt the -program when something unexpected occurs. -
-Both postmaster and postgres have several debug options available. -First, whenever you start the postmaster, make sure you send the -standard output and error to a log file, like: -
- + to questions-request@postgreSQL.org. + + There is also a digest list available. To subscribe to this list, send + email to: questions-digest-request@postgreSQL.org with a BODY of: + + + subscribe + end + + Digests are sent out to members of this list whenever the main list + has received around 30k of messages. + + There is a bugs mailing list available. To subscribe to this list, + send email to bugs-request@postgreSQL.org with a BODY of: + + There is also a developers discussion mailing list available. To + subscribe to this list, send email to hackers-request@postgreSQL.org + with a BODY of: + + + subscribe + end + + Additional information about PostgreSQL can be found via the + PostgreSQL WWW home page at: + + http://postgreSQL.org + + 1.6) Latest release of PostgreSQL + + The latest release of PostgreSQL is version 6.3, which was released on + March 1st, 1998. + + We plan to have major releases every three months. + + 1.7) Is there a commercial version of PostgreSQL? + + Illustra Information Technology (a wholly owned subsidiary of Informix + Software, Inc.) sells an object-relational DBMS called Illustra that + was originally based on postgres. Illustra has cosmetic similarities + to PostgreSQL but has more features, is more robust, performs better, + and offers real documentation and support. On the flip side, it costs + money. For more information, contact sales@illustra.com + + 1.8) What documentation is available for PostgreSQL? + + A user manual, manual pages, and some small test examples are included + in the distribution. The sql and built-in manual pages are + particularly important. + + The www page contains pointers to an implementation guide and five + papers written about postgres design concepts and features. + + 1.9) What version of SQL does PostgreSQL use? + + PostgreSQL supports a subset of SQL-92. It has most of the important + constructs but lacks some of the functionality. The most visible + differences are: + * no HAVING clause under a GROUP BY + + On the other hand, you get to create user-defined types, functions, + inheritance etc. + + 1.10) Does PostgreSQL work with databases from earlier versions of postgres? + + PostgreSQL v1.09 is compatible with databases created with v1.01. + + Upgrading to 6.3 from earlier releases requires a dump and restore. + + Upgrading to 6.2.1 from pre-6.2 requires a dump and restore. + + Upgrading to 6.2.1 from 6.2 does not require a dump, but see the + appropriate /migration file in the distribution. + + Those ugrading from versions earlier than 1.09 must upgrade to 1.09 + first without a dump/reload, then dump the data from 1.09, and then + load it into 6.2.1 or 6.3 beta. + + 1.11) Are there ODBC drivers for PostgreSQL? + + There are two ODBC drivers available, PostODBC and OpenLink ODBC. + + PostODBC is included in the distribution. For all people being + interested in PostODBC, there are now two mailing lists devoted to the + discussion of PostODBC. The mailing lists are: + * postodbc-users@listserv.direct. net + * postodbc-developers@listse rv.direct.net + + these lists are ordinary majordomo mailing lists. You can subscribe by + sending a mail to: + * majordomo@listserv.direct.net + + OpenLink ODBC is very popular. You can get it from + http://www.openlinksw.com/postgres.html. It works with our standard + ODBC client software so you'll have Postgres ODBC available on every + client platform we support (Win, Mac, Unix, VMS). + + We will probably be selling this product to people who need + commercial-quality support, but a freeware version will always be + available. Questions to postgres95@openlink.co.uk. + + 1.12) What tools are available for hooking postgres to Web pages? + + A nice introduction to Database-backed Web pages can be seen at: + http://www.webtools.com + + For web integration, PHP is an excellent interface. The URL for that + is http://www.php.net + + PHP is great for simple stuff, but for more complex stuff, some still + use the perl interface and CGI.pm. + + An WWW gatway based on WDB using perl can be downloaded from: + * http://www.eol.ists.ca/~dunlop/wdb -p95 + + 1.13) Does PostgreSQL have a graphical user interface? A report generator? A + embedded query language interface? + + We have a nice graphical user interface called pgaccess, which is + shipped as part of the distribtion. Pgaccess also has a report + generator. + + We also have ecpg, which is an embedded SQL query language interface + for C. This is also included. + + 1.14) What is a good book to learn SQL? + + Many of our users like The Practical SQL Handbook, Bowman et al, + Addison Wesley. + _________________________________________________________________ + +Section 2: Installation Questions + + 2.1) initdb doesn't run + + * check to see that you have the proper paths set + * check that the 'postgres' user owns all the right files + * ensure that there are files in $PGDATA/files, and that they are + non-empty. If they aren't, then "gmake install" failed for some + reason + + 2.2) when I start up the postmaster, I get "FindBackend: could not find a + backend to execute..." "postmaster: could not find backend to execute..." + + You probably do not have the right path set up. The 'postgres' + executable needs to be in your path. + + 2.3) The system seems to be confused about commas, decimal points, and date + formats. + + Check your locale configuration. PostgreSQL uses the locale settings + of the user that ran the postmaster process. Set those accordingly for + your operating environment. + + 2.4) How do I install PostgreSQL somewhere other than /usr/local/pgsql? + + You need to edit Makefile.global and change POSTGRESDIR accordingly, + or create a Makefile.custom and define POSTGRESDIR there. + + 2.5) When I run postmaster, I get a Bad System Call core dumped message. + + It could be a variety of problems, but first check to see that you + have system V extensions installed on your kernel. PostgreSQL requires + kernel support for shared memory. + + 2.6) When I try to start the postmaster, I get IpcMemoryCreate errors. + + You either do not have shared memory configured properly in kernel or + you need to enlarge the shared memory available in the kernel. The + exact amount you need depends on your architecture and how many + buffers you configure postmaster to run with. For most systems, with + default buffer sizes, you need a minimum of ~760K. + + 2.7) I have changed a source file, but a recompile does not see the change? + + The Makefiles do not have the proper dependencies for include files. + You have to do a 'make clean' and then another 'make'. + + 2.8) How do I prevent other hosts from accessing my PostgreSQL backend? + + By default, PostgreSQL only allows connections from the local machine + using unix domain. You must add the -i flag to the postmaster, and + enable host-based authentication by modifying the file $PGDATA/pg_hba + accordingly. + + 2.9) I can't access the database as the 'root' user. + + You should not create database users with user id 0(root). They will + be unable to access the database. This is a security precaution + because of the ability of any user to dynamically link object modules + into the database engine. + + 2.10) All my servers crash under concurrent table access. Why? + + This problem can be caused by a kernel that is not configured to + support semaphores. + + 2.11) How do I tune the database engine for better performance? + + There are two things that can be done. You can disable fsync() by + starting the postmaster with a '-o -F' option. This will prevent + fsync()'s from flushing to disk after every transaction. + + You can also use the postmaster -B option to increase the number of + shared memory buffers shared among the backend processes. If you make + this parameter too high, the process will not start or crash + unexpectedly. Each buffer is 8K and the defualt is 64 buffers. + + You can also use the postgres -S option to increase the maximum amount + of memory used by each backend process for temporary sorts. Each + buffer is 1K and the defualt is 512 buffers. + + 2.12) What debugging features are available in PostgreSQL? + + PostgreSQL has several features that report status information that + can be valuable for debugging purposes. + + First, by running configure with the -enable-cassert option, many + assert()'s monitor the progress of the backend and halt the program + when something unexpected occurs. + + Both postmaster and postgres have several debug options available. + First, whenever you start the postmaster, make sure you send the + standard output and error to a log file, like: + + cd /usr/local/pgsql - ./bin/postmaster >server.log 2>&1 & - --
-This will put a server.log file in the top-level PostgreSQL directory. -This file can contain useful information about problems or errors -encountered by the server. Postmaster has a -d option that allows even -more detailed information to be reported. The -d option takes a number -1-3 that specifies the debug level. Be warned that a debug level -of 3 generates large log files. -
-You can actuall run the postgres backend from the command line, and type -your SQL statement directly. This is recommended ONLY for debugging -purposes. Note that a newline terminates the query, not a semicolon. If -you have compiled with debugging symbols, you can use a debugger -to see what is happening. Because the backend was not started from the -postmaster, it is not running in an identical environment and -locking/backend interaction problems may not be duplicated. Some -operating system can attach to a running backend directly to diagnose -problems. -
-The postgres program has a -s, -A, -t options that can be very usefull -for debugging and performance measurements. -
-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/base/dbname directory. The client profile file will be put -in the current directory. -
-The EXPLAIN command (see this FAQ) allows you to see how PostgreSQL is -interpreting your query. -
-
-Edit include/storage/sinvaladt.h, and change the value of MaxBackendId. -In the future, we plan to make this a configurable prameter. -
+ ./bin/postmaster >server.log 2>&1 & -
-
-Yes. -
-
-Currently, the rule system in PostgreSQL has some limitations. It works -enough to support the view mechanism, but does not handle -Insert/Update/Delete well. -
-
-The Inversion large object system now works perfectly. You should no -longer have problems with large objects. -
-
-PostgreSQL supports a C-callable library interface called libpq as well -as many others. See the /src/interfaces directory. -
-Others have contributed a perl interface and a WWW gateway to -PostgreSQL. See the PostgreSQL home pages for more details. -
-
-Currently, there is no easy interface to set up user groups. You have to -explicitly insert/update the pg_group table. For example: -
-
- jolly=> insert into pg_group (groname, grosysid, grolist)
- jolly=> values ('posthackers', '1234', '{5443, 8261}');
+ This will put a server.log file in the top-level PostgreSQL directory.
+ This file can contain useful information about problems or errors
+ encountered by the server. Postmaster has a -d option that allows even
+ more detailed information to be reported. The -d option takes a number
+ 1-3 that specifies the debug level. Be warned that a debug level of 3
+ generates large log files.
+
+ You can actuall run the postgres backend from the command line, and
+ type your SQL statement directly. This is recommended ONLY for
+ debugging purposes. Note that a newline terminates the query, not a
+ semicolon. If you have compiled with debugging symbols, you can use a
+ debugger to see what is happening. Because the backend was not started
+ from the postmaster, it is not running in an identical environment and
+ locking/backend interaction problems may not be duplicated. Some
+ operating system can attach to a running backend directly to diagnose
+ problems.
+
+ The postgres program has a -s, -A, -t options that can be very usefull
+ for debugging and performance measurements.
+
+ 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/base/dbname directory. The client profile file will be put
+ in the current directory.
+
+ The EXPLAIN command (see this FAQ) allows you to see how PostgreSQL is
+ interpreting your query.
+
+ 2.13) How do I enable more than 32 concurrent backends?
+
+ Edit include/storage/sinvaladt.h, and change the value of
+ MaxBackendId. In the future, we plan to make this a configurable
+ prameter.
+ _________________________________________________________________
+
+Section 3: PostgreSQL Features
+
+ 3.1) Does PostgreSQL support nested subqueries?
+
+ Yes.
+
+ 3.2) I've having a lot of problems using rules.
+
+ Currently, the rule system in PostgreSQL has some limitations. It
+ works enough to support the view mechanism, but does not handle
+ Insert/Update/Delete well.
+
+ 3.3) I can't seem to write into the middle of large objects reliably.
+
+ The Inversion large object system now works perfectly. You should no
+ longer have problems with large objects.
+
+ 3.4) How can I write client applications to PostgreSQL?
+
+ PostgreSQL supports a C-callable library interface called libpq as
+ well as many others. See the /src/interfaces directory.
+
+ Others have contributed a perl interface and a WWW gateway to
+ PostgreSQL. See the PostgreSQL home pages for more details.
+
+ 3.5) How do I set up a pg_group?
+
+ Currently, there is no easy interface to set up user groups. You have
+ to explicitly insert/update the pg_group table. For example:
+
+
+ jolly=> insert into pg_group (groname, grosysid, grolist)
+ jolly=> values ('posthackers', '1234', '{5443, 8261}');
INSERT 548224
- jolly=> grant insert on foo to group posthackers;
+ jolly=> grant insert on foo to group posthackers;
CHANGE
- jolly=>
-
-
-- The fields in pg_group are: -
-
-See the declare manual page for a description. -
-
-An r-tree index is used for indexing spatial data. A hash index can't -handle range searches. A B-tree index only handles range searches in a -single dimension. R-tree's can handle multi-dimensional data. For -example, if a R-tree index can be built on an attribute of type 'point', -the system can more efficient answer queries like select all points -within a bounding rectangle. -
-The canonical paper that describes the original R-Tree design is: -
-Guttman, A. "R-Trees: A Dynamic Index Structure for Spatial Searching." -Proc of the 1984 ACM SIGMOD Int'l Conf on Mgmt of Data, 45-57. -
-You can also find this paper in Stonebraker's "Readings in Database -Systems" -
-Builtin R-Trees can handle polygons and boxes. In theory, R-trees can -be extended to handle higher number of dimensions. In practice, -extending R-trees require a bit of work and we don't currently have any -documentation on how to do it. -
-
-Tuples are limited to 8K bytes. Taking into account system attributes -and other overhead, one should stay well shy of 8,000 bytes to be on the -safe side. To use attributes larger than 8K, try using the large -objects interface. -
-Tuples do not cross 8k boundaries so a 5k tuple will require 8k of -storage. -
-
-PostgreSQL does not automatically maintain statistics. One has to make -an explicit 'vacuum' call to update the statistics. After statistics -are updated, the optimizer has a better shot at using indices. Note -that the optimizer is limited and does not use indices in some -circumstances (such as OR clauses). For column-specific optimization -statistics, use 'vacuum analyze'. -
-If the system still does not see the index, it is probably because you -have created an index on a field with the improper *_ops type. For -example, you have created a CHAR(4) field, but have specified a char_ops -index type_class. -
-See the create_index manual page for information on what type classes -are available. It must match the field type. -
-Postgres does not warn the user when the improper index is created. -
-Indexes not used for ORDER BY operations. -
-
-See the pgbuiltin manual page. Search for regular expression. -
-
-See the vacuum manual page. -
-
+ jolly=> + + The fields in pg_group are: + * groname: the group name. This a char16 and should be purely + alphanumeric. Do not include underscores or other punctuation. + * grosysid: the group id. This is an int4. This should be unique for + each group. + * grolist: the list of pg_user id's that belong in the group. This + is an int4[]. + + 3.6) What is the exact difference between binary cursors and normal cursors? + + See the declare manual page for a description. + + 3.7) What is a R-tree index and what is it used for? + + An r-tree index is used for indexing spatial data. A hash index can't + handle range searches. A B-tree index only handles range searches in a + single dimension. R-tree's can handle multi-dimensional data. For + example, if a R-tree index can be built on an attribute of type + 'point', the system can more efficient answer queries like select all + points within a bounding rectangle. + + The canonical paper that describes the original R-Tree design is: + + Guttman, A. "R-Trees: A Dynamic Index Structure for Spatial + Searching." Proc of the 1984 ACM SIGMOD Int'l Conf on Mgmt of Data, + 45-57. + + You can also find this paper in Stonebraker's "Readings in Database + Systems" + + Builtin R-Trees can handle polygons and boxes. In theory, R-trees can + be extended to handle higher number of dimensions. In practice, + extending R-trees require a bit of work and we don't currently have + any documentation on how to do it. + + 3.8) What is the maximum size for a tuple? + + Tuples are limited to 8K bytes. Taking into account system attributes + and other overhead, one should stay well shy of 8,000 bytes to be on + the safe side. To use attributes larger than 8K, try using the large + objects interface. + + Tuples do not cross 8k boundaries so a 5k tuple will require 8k of + storage. + + 3.9) I defined indices but my queries don't seem to make use of them. Why? + + PostgreSQL does not automatically maintain statistics. One has to make + an explicit 'vacuum' call to update the statistics. After statistics + are updated, the optimizer has a better shot at using indices. Note + that the optimizer is limited and does not use indices in some + circumstances (such as OR clauses). For column-specific optimization + statistics, use 'vacuum analyze'. + + If the system still does not see the index, it is probably because you + have created an index on a field with the improper *_ops type. For + example, you have created a CHAR(4) field, but have specified a + char_ops index type_class. + + See the create_index manual page for information on what type classes + are available. It must match the field type. + + Postgres does not warn the user when the improper index is created. + + Indexes not used for ORDER BY operations. + + 3.10) How do I do regular expression searches? case-insensitive regexp + searching? + + See the pgbuiltin manual page. Search for regular expression. + + 3.11) I experienced a server crash during a vacuum. How do I remove the lock + file? + + See the vacuum manual page. + + 3.12) What is the difference between the various character types? + Type Internal Name Notes -------------------------------------------------- CHAR char 1 character } @@ -723,185 +603,166 @@ CHAR(#) bpchar blank padded to the specified fixed length VARCHAR(#) varchar size specifies maximum length, no padding TEXT text length limited only by maximum tuple length BYTEA bytea variable-length array of bytes --
-You need to use the internal name when doing internal operations. -
-The last four types above are "varlena" types (i.e. the first four bytes -are the length, followed by the data). CHAR(#) allocates the maximum -number of bytes no matter how much data is stored in the field. -TEXT, VARCHAR(#), and BYTEA all have variable length on the disk, and -because of this, there is a small performance penalty for using them. -Specifically, the penalty is for access to any columns after the first -column of this type. -
-
-You test the column with IS NULL and IS NOT NULL. -
-
-See the explain manual page. -
-
-Postgres does not allow the user to specifiy a user column as type -SERIAL. Instead, you can use each row's oid field as a unique value. -However, if you need to dump and reload the database, you need to use -pgdump's -o option or COPY's WITH OIDS option to preserver the oids. -
-We also have a SEQUENCE function that is similar to SERIAL. See the -create_sequence manual page. -
-Another valid way of doing this is to create a function: -
-
+
+ You need to use the internal name when doing internal operations.
+
+ The last four types above are "varlena" types (i.e. the first four
+ bytes are the length, followed by the data). CHAR(#) allocates the
+ maximum number of bytes no matter how much data is stored in the
+ field. TEXT, VARCHAR(#), and BYTEA all have variable length on the
+ disk, and because of this, there is a small performance penalty for
+ using them. Specifically, the penalty is for access to any columns
+ after the first column of this type.
+
+ 3.13) In a query, how do I detect if a field is NULL?
+
+ You test the column with IS NULL and IS NOT NULL.
+
+ 3.14) How do I see how the query optimizer is evaluating my query?
+
+ See the explain manual page.
+
+ 3.15) How do I create a serial field?
+
+ Postgres does not allow the user to specifiy a user column as type
+ SERIAL. Instead, you can use each row's oid field as a unique value.
+ However, if you need to dump and reload the database, you need to use
+ pgdump's -o option or COPY's WITH OIDS option to preserver the oids.
+
+ We also have a SEQUENCE function that is similar to SERIAL. See the
+ create_sequence manual page.
+
+ Another valid way of doing this is to create a function:
+
create table my_oids (f1 int4);
insert into my_oids values (1);
create function new_oid () returns int4 as
'update my_oids set f1 = f1 + 1; select f1 from my_oids; '
language 'sql';
-
-
--then: -
-
+
+ then:
+
create table my_stuff (my_key int4, value text);
insert into my_stuff values (new_oid(), 'hello');
-
-
--However, keep in mind there is a race condition here where one server -could do the update, then another one do an update, and they both could -select the same new id. This statement should be performed within a -transaction. -
-Yet another way is to use general trigger function autoinc() -from contrib/spi/autoinc.c. -
-
-They are temporary sort files generated by the query executor. -For example, if a sort needs to be done to satisfy an ORDER BY, -some temp files are generated as a result of the sort. -
-If you have no transactions or sorts running at the time, it is safe to -delete the pg_psort.XXX files. -
-
-The default configuration allows only unix domain socket connections -from the local machine. To enable TCP/IP connections, use the -postmaster -i option You need to add a host entry to the file -pgsql/data/pg_hba. See the hba_conf manual page. -
-
-psql has a variety of backslash commands to show such information. Use -\? to see them. -
-Also try the file pgsql/src/tutorial/syscat.source. It illustrates many of -the 'select's needed to get information out of the database system -tables. -
-
-PostgreSQL no longer supports this feature. All support code has been -removed. This was done to improve performance and reduce disk storage -overhead. -
-
-Oids are Postgres's answer to unique row ids or serial columns. Every -row that is created in Postgres gets a unique oid. All oids generated -by initdb are less than 16384 (from backend/access/transam.h). All -post-initdb (user-created) oids are equal or greater that this. All -these oids are unique not only within a table, or database, but unique -within the entire postgres installation. -
-Postgres uses oids in its internal system tables to link rows in -separate tables. These oids can be used to identify specific user rows -and used in joins. It is recommended you use column type oid to store -oid values. See the sql(l) manual page to see the other internal -columns. You can create an index on the oid field for faster access. -
-Tids are used to indentify specific physical rows with block and offset -values. Tids change after rows are modified or reloaded. They are used -by index entries to point to physical rows. They can not be accessed -through sql. -
-
-Some of the source code and older documentation use terms that have more -common usage. Here are some: -
-Please let me know if you think of any more. -
-
-The GEQO module in PostgreSQL is intended to solve the query -optimization problem of joining many tables by means of a Genetic -Algorithm (GA). It allows the handling of large join queries through -non-exhaustive search. -
-For further information see README.GEQO <utesch@aut.tu-freiberg.de>. -
-
-
+
+ However, keep in mind there is a race condition here where one server
+ could do the update, then another one do an update, and they both
+ could select the same new id. This statement should be performed
+ within a transaction.
+
+ Yet another way is to use general trigger function autoinc() from
+ contrib/spi/autoinc.c.
+
+ 3.16) What are the pg_psort.XXX files in my database directory?
+
+ They are temporary sort files generated by the query executor. For
+ example, if a sort needs to be done to satisfy an ORDER BY, some temp
+ files are generated as a result of the sort.
+
+ If you have no transactions or sorts running at the time, it is safe
+ to delete the pg_psort.XXX files.
+
+ 3.17) Why can't I connect to my database from another machine?
+
+ The default configuration allows only unix domain socket connections
+ from the local machine. To enable TCP/IP connections, use the
+ postmaster -i option You need to add a host entry to the file
+ pgsql/data/pg_hba. See the hba_conf manual page.
+
+ 3.18) How do I find out what indexes or operations are defined in the
+ database?
+
+ psql has a variety of backslash commands to show such information. Use
+ \? to see them.
+
+ Also try the file pgsql/src/tutorial/syscat.source. It illustrates
+ many of the 'select's needed to get information out of the database
+ system tables.
+
+ 3.19) What is the time-warp feature and how does it relate to vacuum?
+
+ PostgreSQL no longer supports this feature. All support code has been
+ removed. This was done to improve performance and reduce disk storage
+ overhead.
+
+ 3.20) What is an oid? What is a tid?
+
+ Oids are Postgres's answer to unique row ids or serial columns. Every
+ row that is created in Postgres gets a unique oid. All oids generated
+ by initdb are less than 16384 (from backend/access/transam.h). All
+ post-initdb (user-created) oids are equal or greater that this. All
+ these oids are unique not only within a table, or database, but unique
+ within the entire postgres installation.
+
+ Postgres uses oids in its internal system tables to link rows in
+ separate tables. These oids can be used to identify specific user rows
+ and used in joins. It is recommended you use column type oid to store
+ oid values. See the sql(l) manual page to see the other internal
+ columns. You can create an index on the oid field for faster access.
+
+ Tids are used to indentify specific physical rows with block and
+ offset values. Tids change after rows are modified or reloaded. They
+ are used by index entries to point to physical rows. They can not be
+ accessed through sql.
+
+ 3.21) What is the meaning of some of the terms used in Postgres?
+
+ Some of the source code and older documentation use terms that have
+ more common usage. Here are some:
+ * row, record, tuple
+ * attribute, field, column
+ * table, class
+ * retrieve, select
+ * replace, update
+ * append, insert
+ * oid, serial value
+ * portal, cursor
+ * range variable, table name, table alias
+
+ Please let me know if you think of any more.
+
+ 3.22) What is Genetic Query Optimization?
+
+ The GEQO module in PostgreSQL is intended to solve the query
+ optimization problem of joining many tables by means of a Genetic
+ Algorithm (GA). It allows the handling of large join queries through
+ non-exhaustive search.
+
+ For further information see README.GEQO .
+
+ 3.23) How do you remove a column from a table?
+
+ We do not support ALTER TABLE DROP COLUMN, but do this:
+
SELECT ... -- select all columns but the one you want to remove
INTO TABLE new_table
FROM old_table;
DROP TABLE old_table;
ALTER TABLE new_table RENAME TO old_table;
-
-
--
-See the fetch manual page. -
-This only prevents all row results from being transfered to the client. -The entire query must be evaluated, even if you only want just first few -rows. -Consider a query that has and ORDER BY. There is no way to return any -rows until the entire query is evaluated and sorted. -
-
-6.2.1 has added some new restricted keywords as we make PostgreSQL more -ANSI-92 compilant. The next release will have this restriction removed. -There is a patch on ftp.postgresql.org that will allow this feature now. -
-
-Consider a file with 300,000 lines with two integers on each line. -The flat file is 2.4MB. The size of the PostgreSQL database file -containing this data can be estimated: -
+ + 3.24) How do SELECT only the first few rows of a query? + + See the fetch manual page. + + This only prevents all row results from being transfered to the + client. The entire query must be evaluated, even if you only want just + first few rows. Consider a query that has and ORDER BY. There is no + way to return any rows until the entire query is evaluated and sorted. + + 3.25) Why can't I create a column named "time"? + + 6.2.1 has added some new restricted keywords as we make PostgreSQL + more ANSI-92 compilant. The next release will have this restriction + removed. There is a patch on ftp.postgresql.org that will allow this + feature now. + + 3.26)How much database disk space is required to store data from a typical + flat file? + + Consider a file with 300,000 lines with two integers on each line. The + flat file is 2.4MB. The size of the PostgreSQL database file + containing this data can be estimated: + 40 bytes + each row header (approximate) 8 bytes + two int fields @ 4 bytes each 4 bytes + pointer on page to tuple @@ -919,67 +780,52 @@ The data page size in PostgreSQL is 8192(8k) bytes, so: 157 rows per page 1911 database pages * 8192 bytes per page = 15,654,912 or 15.5MB --+ Indexes do not contain as much overhead, but do contain the data that is being indexed, so they can be large also. -
-
-
-The problem could be a number of things. Try testing your user-defined -function in a stand alone test program first. Also, make sure you are -not sending elog NOTICES when the front-end is expecting data, such as -during a type_in() or type_out() functions -
-
-You are pfree'ing something that was not palloc'ed. When writing -user-defined functions, do not include the file "libpq-fe.h". Doing so -will cause your palloc to be a malloc instead of a free. Then, when the -backend pfrees the storage, you get the notice message. -
-
-Please share them with other PostgreSQL users. Send your extensions to -mailing list, and they will eventually end up in the contrib/ -subdirectory. -
-
-This requires extreme wizardry, so extreme that the authors have not -ever tried it, though in principle it can be done. The short answer is -... you can't. This capability is forthcoming in the future. -
+ _________________________________________________________________ + +Section 4: Extending PostgreSQL -
-
-Check the current FAQ at http://postgreSQL.org -
-Also check out our ftp site ftp://ftp.postgreSQL.org/pub to -see if there is a more recent PostgreSQL version. -
-You can also fill out the "bug-template" file and send it to: -
-
-This is the address of the developers mailing list.
-
-
+ 4.1) I wrote a user-defined function and when I run it in psql, it dumps
+ core.
+
+ The problem could be a number of things. Try testing your user-defined
+ function in a stand alone test program first. Also, make sure you are
+ not sending elog NOTICES when the front-end is expecting data, such as
+ during a type_in() or type_out() functions
+
+ 4.2) I get messages of the type NOTICE:PortalHeapMemoryFree: 0x402251d0 not
+ in alloc set!
+
+ You are pfree'ing something that was not palloc'ed. When writing
+ user-defined functions, do not include the file "libpq-fe.h". Doing so
+ will cause your palloc to be a malloc instead of a free. Then, when
+ the backend pfrees the storage, you get the notice message.
+
+ 4.3) I've written some nifty new types and functions for PostgreSQL.
+
+ Please share them with other PostgreSQL users. Send your extensions to
+ mailing list, and they will eventually end up in the contrib/
+ subdirectory.
+
+ 4.4) How do I write a C function to return a tuple?
+
+ This requires extreme wizardry, so extreme that the authors have not
+ ever tried it, though in principle it can be done. The short answer is
+ ... you can't. This capability is forthcoming in the future.
+ _________________________________________________________________
+
+Section 5: Bugs
+ 5.1) How do I make a bug report?
+
+ Check the current FAQ at http://postgreSQL.org
+
+ Also check out our ftp site ftp://ftp.postgreSQL.org/pub to see if
+ there is a more recent PostgreSQL version.
+
+ You can also fill out the "bug-template" file and send it to:
+ * bugs@postgreSQL.org
+
+ This is the address of the developers mailing list.
diff --git a/doc/TODO b/doc/TODO
index 3df2d583ad..82ceb889ba 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -1,8 +1,8 @@
TODO list for PostgreSQL
========================
-Last updated: Fri Feb 27 13:32:53 EST 1998
+Last updated: Sat Feb 28 10:00:29 EST 1998
-Current maintainer: Bruce Momjian (maillist@candle.pha.pa.us)
+Current maintainer: Bruce Momjian (maillist@candle.pha.pa.us)
The most recent version of this document can be viewed at
the PostgreSQL WWW site, http://www.postgreSQL.org.
@@ -13,50 +13,50 @@ A dash(-) marks changes to be in the next release.
Developers who have claimed items are:
-------------------------------------
- * Bruce is Bruce Momjian