Update FAQ.

doc/FAQ

 
                 Frequently Asked Questions (FAQ) for PostgreSQL
                                        
-   Last updated: Mon Jan 27 01:24:42 EST 2003
+   Last updated: Thu Feb 13 23:07:35 EST 2003
    
    Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
    

doc/src/FAQ/FAQ.html

@@ -10,7 +10,7 @@
   alink="#0000ff">
     <H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
 
-    <P>Last updated: Thu Dec  5 00:47:26 EST 2002</P>
+    <P>Last updated: Thu Feb 13 23:07:35 EST 2003</P>
 
     <P>Current maintainer: Bruce Momjian (<A href=
     "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
@@ -318,7 +318,7 @@
 
     <H4><A name="1.7">1.7</A>) What is the latest release?</H4>
 
-    <P>The latest release of PostgreSQL is version 7.2.3.</P>
+    <P>The latest release of PostgreSQL is version 7.3.1.</P>
 
     <P>We plan to have major releases every four months.</P>
 
@@ -536,8 +536,8 @@
     interface?</H4>
 
     Yes, there are several graphical interfaces to PostgreSQL available.
-    These include PgAccess <a href="http://www.pgaccess.com">
-    http://www.pgaccess.com</a>), PgAdmin II (<a
+    These include PgAccess <a href="http://www.pgaccess.org">
+    http://www.pgaccess.org</a>), PgAdmin II (<a
     href="http://www.pgadmin.org">http://www.pgadmin.org</a>,
     Win32-only), RHDB Admin (<a
     href="http://sources.redhat.com/rhdb/">http://sources.redhat.com/rhdb/
@@ -547,10 +547,6 @@
     http://phppgadmin.sourceforge.net/ </a>), a web-based interface to 
     PostgreSQL.
 
-    <P>We have a nice graphical user interface called PgAccess which can
-    also be used as a report generator. The Web page is
-    <A href="http://www.pgaccess.org/">http://www.pgaccess.org/</A>.</P>
-
     <H4><A name="2.4">2.4</A>) What languages are able to communicate with 
     PostgreSQL?</H4>
 
@@ -757,11 +753,6 @@
     the number of allowed backend processes is so your system won't run
     out of resources.</P>
 
-    <P>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
-    <I>include/storage/sinvaladt.h</I>.</P>
-
     <H4><A name="3.9">3.9</A>) What is in the <I>pgsql_tmp</I> directory?</H4>
 
     <P>This directory contains temporary files generated by the query 
@@ -947,6 +938,10 @@
     LIMIT 1;
 </PRE>
 
+    <P>If you believe the optimizer is incorrect in choosing a
+    sequential scan, use <CODE>SET enable_seqscan TO 'off'</CODE> and
+    run tests to see if an index scan is indeed faster.</P>
+
     <P>When using wild-card operators such as <SMALL>LIKE</SMALL> or
     <I>~</I>, indexes can only be used in certain circumstances:</P>
     <UL>
@@ -1039,10 +1034,10 @@
 <PRE>
 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)
 </PRE>
 
@@ -1056,11 +1051,13 @@ BYTEA           bytea           variable-length byte array (null-byte safe)
     stored out-of-line by <SMALL>TOAST</SMALL>, so the space on disk
     might also be less than expected.</P>
 
-    <P><SMALL>CHAR(n)</SMALL> is best when storing strings that are
-    usually the same length. <SMALL>VARCHAR(n)</SMALL> is best when
-    storing variable-length strings but it limits how long a string can
-    be. <SMALL>TEXT</SMALL> is for strings of unlimited length, maximum
-    1 gigabyte. <SMALL>BYTEA</SMALL> is for storing binary data,
+    <SMALL>VARCHAR(n)</SMALL> is best when storing variable-length
+    strings and it limits how long a string can be. <SMALL>TEXT</SMALL>
+    is for strings of unlimited length, with a maximum of one gigabyte.
+    <P><SMALL>CHAR(n)</SMALL> is for storing strings that are all the
+    same length. <SMALL>CHAR(n)</SMALL> pads with blanks to the specified
+    length, while <SMALL>VARCHAR(n)</SMALL> only stores the characters
+    supplied.  <SMALL>BYTEA</SMALL> is for storing binary data,
     particularly values that include <SMALL>NULL</SMALL> bytes. These
     types have similar performance characteristics.</P>
 
@@ -1286,7 +1283,7 @@ BYTEA           bytea           variable-length byte array (null-byte safe)
 </PRE>
 
     For this to be fast, <CODE>subcol</CODE> should be an indexed column.
-    We hope to fix this limitation in a future release.
+    This preformance problem will be fixed in 7.4.
 
     <H4><A name="4.23">4.23</A>) How do I perform an outer join?</H4>