10
10
alink ="#0000ff ">
11
11
< H1 > Frequently Asked Questions (FAQ) for PostgreSQL</ H1 >
12
12
13
- < P > Last updated: Thu Dec 5 00:47:26 EST 2002 </ P >
13
+ < P > Last updated: Thu Feb 13 23:07:35 EST 2003 </ P >
14
14
15
15
< P > Current maintainer: Bruce Momjian (< A href =
16
16
"mailto:pgman@candle.pha.pa.us "> pgman@candle.pha.pa.us</ A > )< BR >
@@ -318,7 +318,7 @@ <H4><A name="1.6">1.6</A>) Where can I get support?</H4>
318
318
319
319
< H4 > < A name ="1.7 "> 1.7</ A > ) What is the latest release?</ H4 >
320
320
321
- < P > The latest release of PostgreSQL is version 7.2.3 .</ P >
321
+ < P > The latest release of PostgreSQL is version 7.3.1 .</ P >
322
322
323
323
< P > We plan to have major releases every four months.</ P >
324
324
@@ -536,8 +536,8 @@ <H4><A name="2.3">2.3</A>) Does PostgreSQL have a graphical user
536
536
interface?</ H4 >
537
537
538
538
Yes, there are several graphical interfaces to PostgreSQL available.
539
- These include PgAccess < a href ="http://www.pgaccess.com ">
540
- http://www.pgaccess.com </ a > ), PgAdmin II (< a
539
+ These include PgAccess < a href ="http://www.pgaccess.org ">
540
+ http://www.pgaccess.org </ a > ), PgAdmin II (< a
541
541
href ="http://www.pgadmin.org "> http://www.pgadmin.org</ a > ,
542
542
Win32-only), RHDB Admin (< a
543
543
href ="http://sources.redhat.com/rhdb/ "> http://sources.redhat.com/rhdb/
@@ -547,10 +547,6 @@ <H4><A name="2.3">2.3</A>) Does PostgreSQL have a graphical user
547
547
http://phppgadmin.sourceforge.net/ </ a > ), a web-based interface to
548
548
PostgreSQL.
549
549
550
- < P > We have a nice graphical user interface called PgAccess which can
551
- also be used as a report generator. The Web page is
552
- < A href ="http://www.pgaccess.org/ "> http://www.pgaccess.org/</ A > .</ P >
553
-
554
550
< H4 > < A name ="2.4 "> 2.4</ A > ) What languages are able to communicate with
555
551
PostgreSQL?</ H4 >
556
552
@@ -757,11 +753,6 @@ <H4><A name="3.8">3.8</A>) Why do I get <I>"Sorry, too many
757
753
the number of allowed backend processes is so your system won't run
758
754
out of resources.</ P >
759
755
760
- < P > In PostgreSQL versions prior to 6.5, the maximum number of
761
- backends was 64, and changing it required a rebuild after altering
762
- the MaxBackendId constant in
763
- < I > include/storage/sinvaladt.h</ I > .</ P >
764
-
765
756
< H4 > < A name ="3.9 "> 3.9</ A > ) What is in the < I > pgsql_tmp</ I > directory?</ H4 >
766
757
767
758
< P > This directory contains temporary files generated by the query
@@ -947,6 +938,10 @@ <H4><A name="4.8">4.8</A>) My queries are slow or don't make use of
947
938
LIMIT 1;
948
939
</ PRE >
949
940
941
+ < P > If you believe the optimizer is incorrect in choosing a
942
+ sequential scan, use < CODE > SET enable_seqscan TO 'off'</ CODE > and
943
+ run tests to see if an index scan is indeed faster.</ P >
944
+
950
945
< P > When using wild-card operators such as < SMALL > LIKE</ SMALL > or
951
946
< I > ~</ I > , indexes can only be used in certain circumstances:</ P >
952
947
< UL >
@@ -1039,10 +1034,10 @@ <H4><A name="4.14">4.14</A>) What is the difference between the
1039
1034
< PRE >
1040
1035
Type Internal Name Notes
1041
1036
--------------------------------------------------
1042
- "char" char 1 character
1043
- CHAR(n) bpchar blank padded to the specified fixed length
1044
1037
VARCHAR(n) varchar size specifies maximum length, no padding
1038
+ CHAR(n) bpchar blank padded to the specified fixed length
1045
1039
TEXT text no specific upper limit on length
1040
+ "char" char one character
1046
1041
BYTEA bytea variable-length byte array (null-byte safe)
1047
1042
</ PRE >
1048
1043
@@ -1056,11 +1051,13 @@ <H4><A name="4.14">4.14</A>) What is the difference between the
1056
1051
stored out-of-line by < SMALL > TOAST</ SMALL > , so the space on disk
1057
1052
might also be less than expected.</ P >
1058
1053
1059
- < P > < SMALL > CHAR(n)</ SMALL > is best when storing strings that are
1060
- usually the same length. < SMALL > VARCHAR(n)</ SMALL > is best when
1061
- storing variable-length strings but it limits how long a string can
1062
- be. < SMALL > TEXT</ SMALL > is for strings of unlimited length, maximum
1063
- 1 gigabyte. < SMALL > BYTEA</ SMALL > is for storing binary data,
1054
+ < SMALL > VARCHAR(n)</ SMALL > is best when storing variable-length
1055
+ strings and it limits how long a string can be. < SMALL > TEXT</ SMALL >
1056
+ is for strings of unlimited length, with a maximum of one gigabyte.
1057
+ < P > < SMALL > CHAR(n)</ SMALL > is for storing strings that are all the
1058
+ same length. < SMALL > CHAR(n)</ SMALL > pads with blanks to the specified
1059
+ length, while < SMALL > VARCHAR(n)</ SMALL > only stores the characters
1060
+ supplied. < SMALL > BYTEA</ SMALL > is for storing binary data,
1064
1061
particularly values that include < SMALL > NULL</ SMALL > bytes. These
1065
1062
types have similar performance characteristics.</ P >
1066
1063
@@ -1286,7 +1283,7 @@ <H4><A name="4.22">4.22</A>) Why are my subqueries using
1286
1283
</ PRE >
1287
1284
1288
1285
For this to be fast, < CODE > subcol</ CODE > should be an indexed column.
1289
- We hope to fix this limitation in a future release .
1286
+ This preformance problem will be fixed in 7.4 .
1290
1287
1291
1288
< H4 > < A name ="4.23 "> 4.23</ A > ) How do I perform an outer join?</ H4 >
1292
1289
0 commit comments