+Last updated: Wed Jun 11 10:44:40 EDT 1997
+
+Version: 6.1
+
+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.phtml. +
+Irix-specific questions are answered in +http://postgreSQL.org/docs/FAQ-Irix.phtml. +
+Changes in this version (* = modified, + = new): +
+
+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 6.0, which was released on +January 31, 1997. 6.1 is scheduled for release soon. For information +about what is new in 6.1, see our TODO list on our WWW page. +
+We expect a 7.0 release in several months that will remove time-travel +and reduce by 50% the size of on-disk system columns maintained for each +row in a table. This release will also require a dump and restore. +
+
+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. If you're willing to help with PostgreSQL coding, +eventually we can also add the missing features listed above. +
+
+PostgreSQL v1.09 is compatible with databases created with v1.01. Those +upgrading from 1.0 should read the directions in the +MIGRATION_1.0_TO_1.02 directory. +
+Upgrading to 6.0 requires a dump and restore from previous releases. +
+Upgrading to 6.1 requires a dump and restore from previous releases. +
+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 6.0 or 6.1. +
+
+Since we don't have any licensing or registration scheme, it's +impossible to tell. We do know hundreds copies of PostgreSQL v1.* have +been downloaded, and that there many hundreds of subscribers to the +mailing lists. +
+
+
+
+
+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'. +
+
+
+Column constraints are not supported in PostgreSQL. As a consequence, +the system does not check for duplicates. +
+Under 6.0, create a unique index on the column. Attempts to create +duplicate of that column will report an error. +
+
+Subqueries are not implemented, but they can be simulated using sql +functions. +
+
+PostgreSQL 6.0 supports unique indices. +
+
+Currently, the rule system in PostgreSQL is mostly broken. It works +enough to support the view mechanism, but that's about it. Use +PostgreSQL rules at your own peril. +
+
+The Inversion large object system in PostgreSQL is also mostly broken. +It works well enough for storing large wads of data and reading them +back out, but the implementation has some underlying problems. Use +PostgreSQL large objects at your own peril. +
+
+No. No. No. Not in the official distribution at least. Some users have +reported some success at using 'pgbrowse' and 'onyx' as frontends to +PostgreSQL. Several contributions are working on tk based frontend +tools. Ask on the mailing list. +
+
+PostgreSQL supports a C-callable library interface called libpq as well +as a Tcl-based library interface called libtcl. +
+Others have contributed a perl interface and a WWW gateway to +PostgreSQL. See the PostgreSQL home pages for more details. +
+
+Use host-based authentication by modifying the file $PGDATA/pg_hba +accordingly. +
+
+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;
+ CHANGE
+ jolly=>
+
+
++ The fields in pg_group are: +
+
+Normal cursors return data back in ASCII format. Since data is stored +natively in binary format, the system must do a conversion to produce +the ASCII format. In addition, ASCII formats are often large in size +than binary format. Once the attributes come back in ASCII, often the +client application then has to convert it to a binary format to +manipulate it anyway. +
+Binary cursors give you back the data in the native binary +representation. Thus, binary cursors will tend to be a little faster +since there's less overhead of conversion. +
+However, ASCII is architectural neutral whereas binary representation +can differ between different machine architecture. Thus, if your client +machine uses a different representation than you server machine, getting +back attributes in binary format is probably not what you want. Also, if +your main purpose is displaying the data in ASCII, then getting it back +in ASCII will save you some effort on the client side. +
+
+SQL specifies <> as the inequality operator, and that is what we +have defined for the built-in types. +
+In 6.0, != is equivalent to <>. +
+
+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" +
+
+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). +
+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. +
+
+There are two ODBC drivers available, PostODBC and OpenLink ODBC. +
+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 currently in beta under Linux. 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. +
+
+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. +
+
+PostgreSQL supports the SQL LIKE syntax as well as more general regular +expression searching with the ~ operator. The !~ is the negated regexp +operator. ~* and !~* are the case-insensitive regular expression +operators. +
+
+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. +
+
+If the server crashes during a vacuum command, chances are it will leave +a lock file hanging around. Attempts to re-run the vacuum command +result in +
+ + WARN:can't create lock file -- another vacuum cleaner running? + ++
+If you are sure that no vacuum is actually running, you can remove the +file called "pg_vlock" in your database directory (which is +$PGDATA/base/<dbName>) +
+
Type Internal Name Notes -------------------------------------------------- CHAR char 1 character } @@ -592,343 +676,368 @@ 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 ++
+Remember, you need to use the internal name when creating indexes on +these fields or when doing other internal operations. +
+The last four types above are "varlena" types (i.e. the first four bytes +is the length, followed by the data). CHAR(#) and VARCHAR(#) allocate +the maximum number of bytes no matter how much data is stored in the +field. TEXT and BYTEA are the only character types that have variable +length on the disk. +
+
+PostgreSQL has two builtin keywords, "isnull" and "notnull" (note no +spaces). Version 1.05 and later and 6.* understand IS NULL and IS NOT +NULL. +
+
+Place the word 'EXPLAIN' at the beginning of the query, for example: +
+
+ EXPLAIN SELECT * FROM table1 WHERE age = 23;
+
+
++
+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 be +using postgres version 1.07 or later or 6.* with pgdump's -o option or +COPY's WITH OIDS option to preserver the oids. +
+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: +
+
+ 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. +
+Sequences are implemented in 6.1 +
+
- Remember, you need to use the internal name when creating indexes on
- these fields or when doing other internal operations.
-
- The last four types above are "varlena" types (i.e. the first four
- bytes is the length, followed by the data). CHAR(#) and VARCHAR(#)
- allocate the maximum number of bytes no matter how much data is stored
- in the field. TEXT and BYTEA are the only character types that have
- variable length on the disk.
-
- 3.21) In a query, how do I detect if a field is NULL?
-
- PostgreSQL has two builtin keywords, "isnull" and "notnull" (note no
- spaces). Version 1.05 and later and 6.* understand IS NULL and IS NOT
- NULL.
-
- 3.22) How do I see how the query optimizer is evaluating my query?
-
- Place the word 'EXPLAIN' at the beginning of the query, for example:
-
- EXPLAIN SELECT * FROM table1 WHERE age = 23;
-
- 3.23) 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 be
- using postgres version 1.07 or later or 6.* with pgdump's -o option or
- COPY's WITH OIDS option to preserver the oids.
-
- 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:
-
- 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.
-
- 3.24) How do I create a multi-column index?
-
- In 6.0, you can not directly create a multi-column index using create
- index. You need to define a function which acts on the multiple
- columns, then use create index with that function.
-
- In 6.1, this feature is available.
-
- 3.25) What are the temp_XXX files in my database directory?
-
- They are temp_ 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 temp_ files.
-
- 3.26) Why are my table files not getting any smaller after a delete?
-
- If you run vacuum in pre-6.0, unused rows will be marked for reuse,
- but the file blocks are not released.
-
- In 6.0, vacuum properly shrinks tables.
-
- 3.27) Why can't I connect to my database from another machine?
-
- The default configuration allows only connections from tcp/ip host
- localhost. You need to add a host entry to the file pgsql/data/pg_hba.
-
- 3.28) I get the error 'default index class unsupported' when creating an
- index. How do I do it?
-
- You probably used:
-
- create index idx1 on person using btree (name);
-
- PostgreSQL indexes are extensible, and therefore in pre-6.0, you must
- specify a class_type when creating an index. Read the manual page for
- create index (called create_index).
-
- Version 6.0, if you do not specify a class_type, it defaults to the
- proper type for the column.
-
- 3.29) Why does creating an index crash the backend server?
-
- You have probably defined an incorrect *_ops type class for the field
- you are indexing.
-
- 3.30) How do I specify a decimal constant as a float8, or a string as a text?
- Why am I getting poor precision?
-
- Use the :: operator. It is needed only when the default promotion
- rules fail. i.e.:
-
-
- insert into tab1 values (4.23::float8, '2343'::text)
-
- The default floating-point constant is a float4 in releases prior to
- 1.05. Later releases default to float8.
-
- 3.31) How do I find out what indexes or operations are defined in the
- database?
-
- Run the file pgsql/src/tutorial/syscat.source. It illustrates many of
- the 'select's needed to get information out of the database system
- tables.
-
- 3.32) My database is corrupt. I can't do anything. What should I do?
-
- The 1.02 release has a README file and utility that describes a
- possible cause of the problem and a workaround.
-
- This bug is fixed in 1.02.1.
-
- 3.33) Createdb, destroydb, createuser,destroyuser don't run. Why?
-
- Release 1.02 does not have this problem.
-
- The 1.01 release of PostgreSQL uses a variable called PAGER to filter
- the output of SELECT statements. Unfortunately, this PAGER is used
- even when the standard output is not a terminal.
-
- 3.34) Why do statements require an extra character at the end? Why does
- 'createuser' return 'unexpected last match in input()'? Why does pg_dump
- fail?
-
- You have compile postgres with flex version 2.5.3. There is bug in
- this version of flex. Use flex version 2.5.2 or flex 2.5.4 instead.
- There is a doc/README.flex file which will properly patch the flex
- 2.5.3 source code.
-
- 3.35) All my servers crash under concurrent table access. Why?
-
- This problem can be caused by a kernel that is not configured to
- support semaphores.
-
- 3.36) What tools are available for hooking postgres to Web pages?
-
- For web integration, PHP/FI is an excellent interface. The URL for
- that is http://www.vex.net/php/
-
- PHP is great for simple stuff, but for more complex stuff, some still
- use the perl interface and CGI.pm.
-
- An example of using WWW with C to talk to Postgres is can be tried at:
- * http://postgreSQL.org/~mlc
-
- An WWW gatway based on WDB using perl can be downloaded from:
- * http://www.eol.ists.ca/~dunlop/wdb -p95
-
- 3.37) What is the time-warp feature and how does it relate to vacuum?
-
- PostgreSQL handles data changes differently than most database
- systems. When a row is changed in a table, the original row is marked
- with the time it was changed, and a new row is created with the
- current data. By default, only current rows are used in a table. If
- you specify a date/time after the table name in a FROM clause, you can
- access the data that was current at that time, i.e.
-
-
- SELECT *
- FROM employees ['July 24, 1996 09:00:00']
-
- displays employee rows in the table at the specified time. You can
- specify intervals like [date,date], [date,], [,date], or [,]. This
- last option accesses all rows that ever existed.
-
- INSERTed rows get a timestamp too, so rows that were not in the table
- at the desired time will not appear.
-
- Vacuum removes rows that are no longer current. This time-warp feature
- is used by the engine for rollback and crash recovery. Expiration
- times can be set with purge.
-
- In 6.0, once a table is vacuumed, the creation time of a row may be
- incorrect, causing time-traval to fail.
-
- The time-travel feature will be removed in 7.0.
-
- 3.38) How do I tune the database engine for better performance?
-
- There are two things that can be done. You can use Openlink's option
- to 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.
-
- 3.39) What debugging features are available in PostgreSQL?
-
- PostgreSQL has several features that report status information that
- can be valuable for debugging purposes.
-
- First, by compiling with DEBUG defined, 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. The query plans in a verbose debug
- file can be formatted using the 'indent' program. (You may need to
- remove the '====' lines in 1.* releases.) Be warned that a debug level
- greater than one generates large log files in 1.* releases.
-
- 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
- perhaps 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.
-
- The EXPLAIN command (see this FAQ) allows you to see how PostgreSQL is
- iterpreting your query.
-
- 3.40) 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.
-
- 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.
-
- 3.41) 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.
-
- 3.42) 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
+In 6.1, this feature is available.
+
+
+They are temp_ 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 temp_ files.
+
+
+If you run vacuum in pre-6.0, unused rows will be marked for reuse, but
+the file blocks are not released.
+
+In 6.0, vacuum properly shrinks tables.
+
+
+The default configuration allows only connections from tcp/ip host
+localhost. You need to add a host entry to the file pgsql/data/pg_hba.
+
+
+You probably used:
+
+PostgreSQL indexes are extensible, and therefore in pre-6.0, you must
+specify a class_type when creating an index. Read the manual page for
+create index (called create_index).
+
+Version 6.0, if you do not specify a class_type, it defaults to the
+proper type for the column.
+
+
+You have probably defined an incorrect *_ops type class for the field
+you are indexing.
+
+
+Run the file pgsql/src/tutorial/syscat.source. It illustrates many of
+the 'select's needed to get information out of the database system
+tables.
+
+
+You have compile postgres with flex version 2.5.3. There is bug in this
+version of flex. Use flex version 2.5.2 or flex 2.5.4 instead. There
+is a doc/README.flex file which will properly patch the flex 2.5.3
+source code.
+
+
+This problem can be caused by a kernel that is not configured to support
+semaphores.
+
+
+For web integration, PHP/FI is an excellent interface. The URL for that
+is http://www.vex.net/php/
+
+PHP is great for simple stuff, but for more complex stuff, some still
+use the perl interface and CGI.pm.
+
+An example of using WWW with C to talk to Postgres is can be tried at:
+
+An WWW gatway based on WDB using perl can be downloaded from:
+
+PostgreSQL handles data changes differently than most database systems.
+When a row is changed in a table, the original row is marked with the
+time it was changed, and a new row is created with the current data. By
+default, only current rows are used in a table. If you specify a
+date/time after the table name in a FROM clause, you can access the data
+that was current at that time, i.e.
+
+displays employee rows in the table at the specified time. You can
+specify intervals like [date,date], [date,], [,date], or [,]. This last
+option accesses all rows that ever existed.
+
+INSERTed rows get a timestamp too, so rows that were not in the table at
+the desired time will not appear.
+
+Vacuum removes rows that are no longer current. This time-warp feature
+is used by the engine for rollback and crash recovery. Expiration times
+can be set with purge.
+
+In 6.0, once a table is vacuumed, the creation time of a row may be
+incorrect, causing time-traval to fail.
+
+The time-travel feature will be removed in 7.0.
+
+
+There are two things that can be done. You can use Openlink's option to
+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.
+
+
+PostgreSQL has several features that report status information that can
+be valuable for debugging purposes.
+
+First, by compiling with DEBUG defined, 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:
+
+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. The query plans in a verbose debug
+file can be formatted using the 'indent' program. (You may need to
+remove the '====' lines in 1.* releases.) Be warned that a debug level
+greater than one generates large log files in 1.* releases.
+
+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 perhaps 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.
+
+The EXPLAIN command (see this FAQ) allows you to see how PostgreSQL is
+iterpreting your query.
+
+
+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.
+
+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>.
+
+
+There was a bug in 6.0 that caused this problem under Solaris with -O2
+optimization.
+Upgrade to 6.1.
+
+
+Edit include/storage/sinvaladt.h, and change the value of MaxBackendId.
+In the future, we plan to make this a configurable prameter.
+
+
+
+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.
+
+
+
+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.
+
+
diff --git a/doc/TODO b/doc/TODO
index 519d7903f7c..4257a9cb263 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -122,6 +122,8 @@ add pg_type attribute to identify types that need length (bpchar, varchar)
add UNIQUE capability to non-btree indexes
make pg_dumpall preserve table ownership, not just database ownership
make large objects have their own reltype
+make number of backends a config parameter, storage/sinvaladt.h:MaxBackendId
+certain indexes will not shrink, i.e. oid indexes with many inserts
PERFORMANCE
-----------
3.25) What are the temp_XXX files in my database
+directory?
+3.26) Why are my table files not getting any
+smaller after a delete?
+3.27) Why can't I connect to my database from
+another machine?
+3.28) I get the error 'default index class
+unsupported' when creating an index. How do I do it?
+
+
+
+ create index idx1 on person using btree (name);
+
+3.29) Why does creating an index crash the
+backend server?
+3.30) How do I find out what indexes or
+operations are defined in the database?
+3.31) Why do statements require an extra character at
+the end? Why does 'createuser' return 'unexpected last match in input()'?
+Why does pg_dump fail?
+3.32) All my servers crash under concurrent table
+access. Why?
+3.33) What tools are available for hooking
+postgres to Web pages?
+3.34) What is the time-warp feature and how does
+it relate to vacuum?
+
+
+
+ SELECT *
+ FROM employees ['July 24, 1996 09:00:00']
+
+3.35) How do I tune the database engine for
+better performance?
+3.36) What debugging features are available in
+PostgreSQL?
+
+
+ cd /usr/local/pgsql
+ ./bin/postmaster >server.log 2>&1 &
+
+
+3.37) What is an oid? What is a tid?
+3.38) What is the meaning of some of the terms
+used in Postgres?
+
+
+3.39) What is Genetic Query Optimization?
+3.40) I am running Solaris and my dates
+display wrong. Why?
+3.41) How do I enable more than 32 concurrent
+backends?
+
+ Section 4: 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 not in alloc set!
+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?
+
+ Section 5: Bugs
+
+5.1) How do I make a bug report?
+