From 5458bd2fa55848e5fa0ce1d11b79310669f8ea20 Mon Sep 17 00:00:00 2001
From: Bruce Momjian Last updated: Thu Dec 5 00:47:26 EST 2002 Last updated: Thu Feb 13 23:07:35 EST 2003 Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) The latest release of PostgreSQL is version 7.2.3. The latest release of PostgreSQL is version 7.3.1. We plan to have major releases every four months. We have a nice graphical user interface called PgAccess which can
- also be used as a report generator. The Web page is
- http://www.pgaccess.org/.Frequently Asked Questions (FAQ) for PostgreSQL
-
@@ -318,7 +318,7 @@
1.7) What is the latest release?
- 2.4) What languages are able to communicate with
PostgreSQL?
@@ -757,11 +753,6 @@
the number of allowed backend processes is so your system won't run
out of resources.
In PostgreSQL versions prior to 6.5, the maximum number of - backends was 64, and changing it required a rebuild after altering - the MaxBackendId constant in - include/storage/sinvaladt.h.
-This directory contains temporary files generated by the query @@ -947,6 +938,10 @@ LIMIT 1; +
If you believe the optimizer is incorrect in choosing a
+ sequential scan, use SET enable_seqscan TO 'off'
and
+ run tests to see if an index scan is indeed faster.
When using wild-card operators such as LIKE or ~, indexes can only be used in certain circumstances:
Type Internal Name Notes -------------------------------------------------- -"char" char 1 character -CHAR(n) bpchar blank padded to the specified fixed length VARCHAR(n) varchar size specifies maximum length, no padding +CHAR(n) bpchar blank padded to the specified fixed length TEXT text no specific upper limit on length +"char" char one character BYTEA bytea variable-length byte array (null-byte safe)@@ -1056,11 +1051,13 @@ BYTEA bytea variable-length byte array (null-byte safe) stored out-of-line by TOAST, so the space on disk might also be less than expected. -
CHAR(n) is best when storing strings that are - usually the same length. VARCHAR(n) is best when - storing variable-length strings but it limits how long a string can - be. TEXT is for strings of unlimited length, maximum - 1 gigabyte. BYTEA is for storing binary data, + VARCHAR(n) is best when storing variable-length + strings and it limits how long a string can be. TEXT + is for strings of unlimited length, with a maximum of one gigabyte. +
CHAR(n) is for storing strings that are all the + same length. CHAR(n) pads with blanks to the specified + length, while VARCHAR(n) only stores the characters + supplied. BYTEA is for storing binary data, particularly values that include NULL bytes. These types have similar performance characteristics.
@@ -1286,7 +1283,7 @@ BYTEA bytea variable-length byte array (null-byte safe) For this to be fast,subcol
should be an indexed column.
- We hope to fix this limitation in a future release.
+ This preformance problem will be fixed in 7.4.