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Update FAQ's in head and 7.3.X.

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doc/FAQ
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@ -1,15 +1,15 @@
Frequently Asked Questions (FAQ) for PostgreSQL Frequently Asked Questions (FAQ) for PostgreSQL
Last updated: Tue Dec 17 23:56:27 EST 2002 Last updated: Fri Feb 14 09:03:00 EST 2003
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
The most recent version of this document can be viewed at The most recent version of this document can be viewed at
http://www.PostgreSQL.org/docs/faq-english.html. http://www.ca.PostgreSQL.org/docs/faq-english.html.
Platform-specific questions are answered at Platform-specific questions are answered at
http://www.PostgreSQL.org/users-lounge/docs/faq.html. http://www.ca.PostgreSQL.org/users-lounge/docs/faq.html.
_________________________________________________________________ _________________________________________________________________
General Questions General Questions
@ -242,11 +242,11 @@
Unix command irc -c '#PostgreSQL' "$USER" irc.phoenix.net. Unix command irc -c '#PostgreSQL' "$USER" irc.phoenix.net.
A list of commercial support companies is available at A list of commercial support companies is available at
http://www.PostgreSQL.org/users-lounge/commercial-support.html. http://www.ca.PostgreSQL.org/users-lounge/commercial-support.html.
1.7) What is the latest release? 1.7) What is the latest release?
The latest release of PostgreSQL is version 7.3.1. The latest release of PostgreSQL is version 7.3.2.
We plan to have major releases every four months. We plan to have major releases every four months.
@ -255,7 +255,7 @@
Several manuals, manual pages, and some small test examples are Several manuals, manual pages, and some small test examples are
included in the distribution. See the /doc directory. You can also included in the distribution. See the /doc directory. You can also
browse the manual online at browse the manual online at
http://www.PostgreSQL.org/users-lounge/docs/. http://www.ca.PostgreSQL.org/users-lounge/docs/.
There are two PostgreSQL books available online at There are two PostgreSQL books available online at
http://www.PostgreSQL.org/docs/awbook.html and http://www.PostgreSQL.org/docs/awbook.html and
@ -586,10 +586,6 @@
that PostgreSQL has a limit on the number of allowed backend processes that PostgreSQL has a limit on the number of allowed backend processes
is so your system won't run out of resources. 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.
3.9) What is in the pgsql_tmp directory? 3.9) What is in the pgsql_tmp directory?
This directory contains temporary files generated by the query This directory contains temporary files generated by the query
@ -749,6 +745,10 @@
ORDER BY col [ DESC ] ORDER BY col [ DESC ]
LIMIT 1; 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 When using wild-card operators such as LIKE or ~, indexes can only be
used in certain circumstances: used in certain circumstances:
* The beginning of the search string must be anchored to the start * The beginning of the search string must be anchored to the start
@ -820,10 +820,10 @@
Type Internal Name Notes 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 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 TEXT text no specific upper limit on length
"char" char one character
BYTEA bytea variable-length byte array (null-byte safe) BYTEA bytea variable-length byte array (null-byte safe)
You will see the internal name when examining system catalogs and in You will see the internal name when examining system catalogs and in
@ -834,13 +834,15 @@ BYTEA bytea variable-length byte array (null-byte safe)
space used is slightly greater than the declared size. However, these space used is slightly greater than the declared size. However, these
data types are also subject to compression or being stored out-of-line data types are also subject to compression or being stored out-of-line
by TOAST, so the space on disk might also be less than expected. by TOAST, so the space on disk might also be less than expected.
VARCHAR(n) is best when storing variable-length strings and it limits
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, how long a string can be. TEXT is for strings of unlimited length,
maximum 1 gigabyte. BYTEA is for storing binary data, particularly with a maximum of one gigabyte.
values that include NULL bytes. These types have similar performance
characteristics. 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.
4.15.1) How do I create a serial/auto-incrementing field? 4.15.1) How do I create a serial/auto-incrementing field?
@ -1009,8 +1011,8 @@ CREATE TABLE test (x int, modtime timestamp DEFAULT CURRENT_TIMESTAMP );
FROM tab FROM tab
WHERE EXISTS (SELECT subcol FROM subtab WHERE subcol = col); WHERE EXISTS (SELECT subcol FROM subtab WHERE subcol = col);
For this to be fast, subcol should be an indexed column. We hope to For this to be fast, subcol should be an indexed column. This
fix this limitation in a future release. preformance problem will be fixed in 7.4.
4.23) How do I perform an outer join? 4.23) How do I perform an outer join?

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From: Zeugswetter Andreas <ZeugswetterA@spardat.at> From: Zeugswetter Andreas <ZeugswetterA@spardat.at>
$Date: 2002/12/18 20:39:31 $ $Date: 2003/02/14 14:05:51 $
On AIX 4.3.2 PostgreSQL compiled with the native IBM compiler xlc On AIX 4.3.2 PostgreSQL compiled with the native IBM compiler xlc
(vac.C 5.0.1) passes all regression tests. Other versions of OS and (vac.C 5.0.1) passes all regression tests. Other versions of OS and

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doc/FAQ_DEV
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Developer's Frequently Asked Questions (FAQ) for PostgreSQL Developer's Frequently Asked Questions (FAQ) for PostgreSQL
Last updated: Tue Nov 5 16:52:46 EST 2002 Last updated: Fri Feb 14 08:59:10 EST 2003
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
@ -643,9 +643,8 @@ List *i, *list;
return the i'th element in list. return the i'th element in list.
lconsi, ... lconsi, ...
There are integer versions of these: lconsi, lappendi, nthi. There are integer versions of these: lconsi, lappendi, etc.
List's containing integers instead of Node pointers are used to Also versions for OID lists: lconso, lappendo, etc.
hold list of relation object id's and other integer quantities.
You can print nodes easily inside gdb. First, to disable output You can print nodes easily inside gdb. First, to disable output
truncation when you use the gdb print command: truncation when you use the gdb print command:

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doc/FAQ_HPUX
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@ -3,7 +3,7 @@ Frequently Asked Questions (FAQ) for PostgreSQL 7.3
HP-UX Specific HP-UX Specific
TO BE READ IN CONJUNCTION WITH THE NORMAL FAQ TO BE READ IN CONJUNCTION WITH THE NORMAL FAQ
======================================================= =======================================================
last updated: $Date: 2002/12/18 20:39:31 $ last updated: $Date: 2003/02/14 14:05:51 $
current maintainer: Tom Lane (tgl@sss.pgh.pa.us) current maintainer: Tom Lane (tgl@sss.pgh.pa.us)
original author: Tom Lane (tgl@sss.pgh.pa.us) original author: Tom Lane (tgl@sss.pgh.pa.us)

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doc/FAQ_IRIX
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@ -3,7 +3,7 @@ Frequently Asked Questions (FAQ) for PostgreSQL
IRIX Specific IRIX Specific
TO BE READ IN CONJUNCTION WITH THE NORMAL FAQ TO BE READ IN CONJUNCTION WITH THE NORMAL FAQ
======================================================= =======================================================
last updated: $Date: 2002/12/18 20:39:31 $ last updated: $Date: 2003/02/14 14:05:52 $
current maintainer: Luis Amigo (lamigo@atc.unican.es) current maintainer: Luis Amigo (lamigo@atc.unican.es)
original author: Luis Amigo (lamigo@atc.unican.es) original author: Luis Amigo (lamigo@atc.unican.es)

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doc/FAQ_MSWIN
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How to install PostgreSQL on Windows How to install PostgreSQL on Windows
==================================== ====================================
$Date: 2002/12/18 20:39:31 $ $Date: 2003/02/14 14:05:52 $
1. Install the latest Cygwin package, available at http://cygwin.com/. 1. Install the latest Cygwin package, available at http://cygwin.com/.
The Cygwin package provides a UNIX-like API on top of the Win32 The Cygwin package provides a UNIX-like API on top of the Win32

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doc/FAQ_SCO
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@ -3,7 +3,7 @@ Frequently Asked Questions (FAQ) for PostgreSQL 7.3
SCO UnixWare and OpenServer specific SCO UnixWare and OpenServer specific
to be read in conjunction with the installation instructions to be read in conjunction with the installation instructions
============================================================ ============================================================
last updated: $Date: 2002/12/18 20:39:31 $ last updated: $Date: 2003/02/14 14:05:52 $
current maintainer: Billy G. Allie (Bill.Allie@mug.org) current maintainer: Billy G. Allie (Bill.Allie@mug.org)
original author: Andrew Merrill (andrew@compclass.com) original author: Andrew Merrill (andrew@compclass.com)

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doc/FAQ_Solaris
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@ -3,7 +3,7 @@ Frequently Asked Questions (FAQ) for PostgreSQL
Sun Solaris specific Sun Solaris specific
to be read in conjunction with the installation instructions to be read in conjunction with the installation instructions
============================================================ ============================================================
last updated: $Date: 2002/12/18 20:39:31 $ last updated: $Date: 2003/02/14 14:05:52 $
current maintainer: Peter Eisentraut <peter_e@gmx.net> current maintainer: Peter Eisentraut <peter_e@gmx.net>

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doc/FAQ_russian
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Otvety na chasto zadavaemye voprosy po PostgreSQL Otvety na chasto zadavaemye voprosy po PostgreSQL
Data poslednego obnovleniya: CHetverg 5 Dekabrya 00:47:26 EDT 2002 Data poslednego obnovleniya: CHetverg 13 Fevralya 23:07:35 EDT 2002
Anglijskij variant soprovozhdaet: Bryus Mom'yan (Bruce Momjian) Anglijskij variant soprovozhdaet: Bryus Mom'yan (Bruce Momjian)
(pgman@candle.pha.pa.us) (pgman@candle.pha.pa.us)
@ -275,7 +275,7 @@
1.7) Kakaya poslednyaya versiya? 1.7) Kakaya poslednyaya versiya?
Poslednij vypusk PostgreSQL - `eto versiya 7.2.3. Poslednij vypusk PostgreSQL - `eto versiya 7.3.1.
My planiruem vypuskat' novye versii kazhdye chetyre mesyaca. My planiruem vypuskat' novye versii kazhdye chetyre mesyaca.
@ -469,17 +469,13 @@
2.3) Est' li u PostgreSQL graficheskij interfejs pol'zovatelya? 2.3) Est' li u PostgreSQL graficheskij interfejs pol'zovatelya?
Da, suschestvuet neskol'ko graficheskih interfejsov dlya PostgreSQL. Da, suschestvuet neskol'ko graficheskih interfejsov dlya PostgreSQL.
`Eto PgAccess (http://www.pgaccess.com, PgAdmin II `Eto PgAccess (http://www.pgaccess.org, PgAdmin II
(http://www.pgadmin.org, Win32-only), RHDB Admin ( (http://www.pgadmin.org, Win32-only), RHDB Admin (
http://sources.redhat.com/rhdb/) i Rekall ( http://sources.redhat.com/rhdb/) i Rekall (
http://www.thekompany.com/products/rekall/, kommercheskij). Takzhe http://www.thekompany.com/products/rekall/, kommercheskij). Takzhe
est' PHPPgAdmin ( http://phppgadmin.sourceforge.net/) - interfejs k est' PHPPgAdmin ( http://phppgadmin.sourceforge.net/) - interfejs k
PostgreSQL, osnovannyj na Web. PostgreSQL, osnovannyj na Web.
U nas est' prekrasnyj goraficheskij interfejs, nazyvaemyj PgAccess,
kotoryj takzhe mozhno ispol'zovat' kak generator otchetov. Ego
stranichka http://www.pgaccess.org/
2.4) Kakie yazyki mogut vzaimodejstvovat' s PostgreSQL? 2.4) Kakie yazyki mogut vzaimodejstvovat' s PostgreSQL?
Kakie-libo interfejsy dlya PostgreSQL suschestvuyut dlya bol'shinstva Kakie-libo interfejsy dlya PostgreSQL suschestvuyut dlya bol'shinstva
@ -669,10 +665,6 @@
sozdaniya ogranicheniya na kolichestvo backend processov kak raz i sozdaniya ogranicheniya na kolichestvo backend processov kak raz i
sostoit v tom, chtoby vashej sisteme hvatilo resursov. sostoit v tom, chtoby vashej sisteme hvatilo resursov.
V PostgreSQL do versii 6.5, maksimal'noe kolichestvo backend processov
bylo 64, i izmenenie `etogo kolichestva trebovalo perekompilyacii
posle ustanovki konstanty MaxBackendId v include/storage/sinvaladt.h.
3.9) CHto nahoditsya v kataloge pgsql_tmp? 3.9) CHto nahoditsya v kataloge pgsql_tmp?
Dannyj katalog soderzhit vremennye fajly, generiruemye obrabotchikom Dannyj katalog soderzhit vremennye fajly, generiruemye obrabotchikom
@ -853,6 +845,11 @@ pa
ORDER BY col [ DESC ] ORDER BY col [ DESC ]
LIMIT 1; LIMIT 1;
Esli vam kazhetsya, chto optimizator nekorretno vybiraet
posledovatel'nyj perebor, ispol'zujte SET enable_seqscan TO 'off' i
zapustite testy, chtoby uvidet', ne stalo-li skanirovanie indeksov
bystree.
Kogda ispol'zuyutsya operacii s shablonami, naprimer LIKE ili ~, Kogda ispol'zuyutsya operacii s shablonami, naprimer LIKE ili ~,
indeksy mogut byt' ispol'zovany v sleduyuschih sluchayah: indeksy mogut byt' ispol'zovany v sleduyuschih sluchayah:
* Nachalo stroki poiska dolzhno sovpadat' s nachalom iskomoj stroki, * Nachalo stroki poiska dolzhno sovpadat' s nachalom iskomoj stroki,
@ -929,12 +926,12 @@ pa
Tip Vnutrennee imya Zamechaniya Tip Vnutrennee imya Zamechaniya
-------------------------------------------------- --------------------------------------------------
"char" char 1 simvol
CHAR(n) bpchar zapolnyaetsya pustotoj do fiksirovannoj dliny
VARCHAR(n) varchar razmer zadaet maksimal'nuyu dlinu, net zapolnen VARCHAR(n) varchar razmer zadaet maksimal'nuyu dlinu, net zapolnen
iya iya
CHAR(n) bpchar zapolnyaetsya pustotoj do fiksirovannoj dliny
TEXT text net zadavaemogo verhnego ogranicheniya ili dlin TEXT text net zadavaemogo verhnego ogranicheniya ili dlin
y y
"char" char odin simvol
BYTEA bytea massiv bajt peremennoj dliny (mozhno ispol'zova BYTEA bytea massiv bajt peremennoj dliny (mozhno ispol'zova
t' null-bajt bez opaski) t' null-bajt bez opaski)
@ -948,15 +945,17 @@ t' null-bajt bez opaski)
szhatiyu ili mogut byt' sohraneny ne v strokom vide cherez TOAST, tak szhatiyu ili mogut byt' sohraneny ne v strokom vide cherez TOAST, tak
chto zanimaemoe diskovoe prostranstvo mozhet takzhe byt' i men'she, chto zanimaemoe diskovoe prostranstvo mozhet takzhe byt' i men'she,
chem ozhidalos'. chem ozhidalos'.
VARCHAR(n) - `eto luchshee reshenie, kogda nuzhno hranit' stroki
peremennoj dliny, ne prevyshayuschie opredelennogo razmera. TEXT -
`eto luchshee reshenie dlya strok neogranichennoj dliny, s maksimal'no
dopustimoj dlinoj v 1 gigabajt.
CHAR(n) - `eto luchshee reshenie dlya hraneniya strok, kotorye obychno CHAR(n) - `eto luchshee reshenie dlya hraneniya strok, kotorye obychno
imeyut odinakovuyu dlinu. VARCHAR(n) - `eto luchshee reshenie, kogda imeyut odinakovuyu dlinu. CHAR(n) zapolnyaetsya pustotoj do zadannoj
nuzhno hranit' stroki peremennoj dliny, no ne prevyshayuschie dliny, v to vremya kak VARCHAR(n) hranit tol'ko simvoly, iz kotoryh
opredelennogo razmera. TEXT - `eto luchshee reshenie dlya strok sostoit stroka. BYTEA ispol'zuetsya dlya hraneniya binarnyh dannyh,
neogranichennoj dliny, s maksimal'no dopustimoj dlinoj v 1 gigabajt. znacheniya kotoryh mogut vklyuchat' NULL bajty. `Eti tipy imeyut
BYTEA dlya hraneniya binarnyh dannyh, znacheniya kotoryh mogut shodnye harakteristiki proizvoditel'nosti.
vklyuchat' NULL bajty. `Eti tipy imeyut shodnye harakteristiki
proizvoditel'nosti.
4.15.1) Kak mne sozdat' pole serial/s-avto-uvelicheniem? 4.15.1) Kak mne sozdat' pole serial/s-avto-uvelicheniem?
@ -1146,8 +1145,8 @@ CREATE TABLE test (x int, modtime timestamp DEFAULT CURRENT_TIMESTAMP );
WHERE EXISTS (SELECT subcol FROM subtab WHERE subcol = col); WHERE EXISTS (SELECT subcol FROM subtab WHERE subcol = col);
CHtoby takaya konstrukciya rabotala bystro, kolonka subcol dolzhna CHtoby takaya konstrukciya rabotala bystro, kolonka subcol dolzhna
byt' proindeksirovana. My nadeemsya ubrat' `eto ogranichenie v byt' proindeksirovana. `Eta problema proizvoditel'nosti budet
buduschem vypuske. ustranena v versii 7.4.
4.23) Kak mne vypolnit' vneshnee svyazyvanie? 4.23) Kak mne vypolnit' vneshnee svyazyvanie?

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doc/src/FAQ/FAQ.html
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@ -10,7 +10,7 @@
alink="#0000ff"> alink="#0000ff">
<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1> <H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
<P>Last updated: Thu Dec 5 00:47:26 EST 2002</P> <P>Last updated: Fri Feb 14 09:03:00 EST 2003</P>
<P>Current maintainer: Bruce Momjian (<A href= <P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR> "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
@ -18,10 +18,10 @@
<P>The most recent version of this document can be viewed at <A <P>The most recent version of this document can be viewed at <A
href= href=
"http://www.PostgreSQL.org/docs/faq-english.html">http://www.PostgreSQL.org/docs/faq-english.html</A>.</P> "http://www.ca.PostgreSQL.org/docs/faq-english.html">http://www.ca.PostgreSQL.org/docs/faq-english.html</A>.</P>
<P>Platform-specific questions are answered at <A href= <P>Platform-specific questions are answered at <A href=
"http://www.PostgreSQL.org/users-lounge/docs/faq.html">http://www.PostgreSQL.org/users-lounge/docs/faq.html</A>.</P> "http://www.ca.PostgreSQL.org/users-lounge/docs/faq.html">http://www.ca.PostgreSQL.org/users-lounge/docs/faq.html</A>.</P>
<HR> <HR>
<H2 align="center">General Questions</H2> <H2 align="center">General Questions</H2>
@ -314,11 +314,11 @@
'#PostgreSQL' "$USER" irc.phoenix.net.</CODE></P> '#PostgreSQL' "$USER" irc.phoenix.net.</CODE></P>
<P>A list of commercial support companies is available at <A href= <P>A list of commercial support companies is available at <A href=
"http://www.PostgreSQL.org/users-lounge/commercial-support.html">http://www.PostgreSQL.org/users-lounge/commercial-support.html</A>.</P> "http://www.ca.PostgreSQL.org/users-lounge/commercial-support.html">http://www.ca.PostgreSQL.org/users-lounge/commercial-support.html</A>.</P>
<H4><A name="1.7">1.7</A>) What is the latest release?</H4> <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 7.3.2.</P>
<P>We plan to have major releases every four months.</P> <P>We plan to have major releases every four months.</P>
@ -327,7 +327,7 @@
<P>Several manuals, manual pages, and some small test examples are <P>Several manuals, manual pages, and some small test examples are
included in the distribution. See the <I>/doc</I> directory. You included in the distribution. See the <I>/doc</I> directory. You
can also browse the manual online at <A href= can also browse the manual online at <A href=
"http://www.PostgreSQL.org/users-lounge/docs/">http://www.PostgreSQL.org/users-lounge/docs/</A>.</P> "http://www.ca.PostgreSQL.org/users-lounge/docs/">http://www.ca.PostgreSQL.org/users-lounge/docs/</A>.</P>
<P>There are two PostgreSQL books available online at <A href= <P>There are two PostgreSQL books available online at <A href=
"http://www.PostgreSQL.org/docs/awbook.html">http://www.PostgreSQL.org/docs/awbook.html</A> "http://www.PostgreSQL.org/docs/awbook.html">http://www.PostgreSQL.org/docs/awbook.html</A>
@ -536,8 +536,8 @@
interface?</H4> interface?</H4>
Yes, there are several graphical interfaces to PostgreSQL available. Yes, there are several graphical interfaces to PostgreSQL available.
These include PgAccess <a href="http://www.pgaccess.com"> These include PgAccess <a href="http://www.pgaccess.org">
http://www.pgaccess.com</a>), PgAdmin II (<a http://www.pgaccess.org</a>), PgAdmin II (<a
href="http://www.pgadmin.org">http://www.pgadmin.org</a>, href="http://www.pgadmin.org">http://www.pgadmin.org</a>,
Win32-only), RHDB Admin (<a Win32-only), RHDB Admin (<a
href="http://sources.redhat.com/rhdb/">http://sources.redhat.com/rhdb/ 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 http://phppgadmin.sourceforge.net/ </a>), a web-based interface to
PostgreSQL. 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 <H4><A name="2.4">2.4</A>) What languages are able to communicate with
PostgreSQL?</H4> PostgreSQL?</H4>
@ -757,11 +753,6 @@
the number of allowed backend processes is so your system won't run the number of allowed backend processes is so your system won't run
out of resources.</P> 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> <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 <P>This directory contains temporary files generated by the query
@ -947,6 +938,10 @@
LIMIT 1; LIMIT 1;
</PRE> </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 <P>When using wild-card operators such as <SMALL>LIKE</SMALL> or
<I>~</I>, indexes can only be used in certain circumstances:</P> <I>~</I>, indexes can only be used in certain circumstances:</P>
<UL> <UL>
@ -1039,10 +1034,10 @@
<PRE> <PRE>
Type Internal Name Notes 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 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 TEXT text no specific upper limit on length
"char" char one character
BYTEA bytea variable-length byte array (null-byte safe) BYTEA bytea variable-length byte array (null-byte safe)
</PRE> </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 stored out-of-line by <SMALL>TOAST</SMALL>, so the space on disk
might also be less than expected.</P> might also be less than expected.</P>
<P><SMALL>CHAR(n)</SMALL> is best when storing strings that are <SMALL>VARCHAR(n)</SMALL> is best when storing variable-length
usually the same length. <SMALL>VARCHAR(n)</SMALL> is best when strings and it limits how long a string can be. <SMALL>TEXT</SMALL>
storing variable-length strings but it limits how long a string can is for strings of unlimited length, with a maximum of one gigabyte.
be. <SMALL>TEXT</SMALL> is for strings of unlimited length, maximum <P><SMALL>CHAR(n)</SMALL> is for storing strings that are all the
1 gigabyte. <SMALL>BYTEA</SMALL> is for storing binary data, 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 particularly values that include <SMALL>NULL</SMALL> bytes. These
types have similar performance characteristics.</P> types have similar performance characteristics.</P>
@ -1286,7 +1283,7 @@ BYTEA bytea variable-length byte array (null-byte safe)
</PRE> </PRE>
For this to be fast, <CODE>subcol</CODE> should be an indexed column. 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> <H4><A name="4.23">4.23</A>) How do I perform an outer join?</H4>

8
doc/src/FAQ/FAQ_DEV.html
View File

@ -12,7 +12,7 @@
<H1>Developer's Frequently Asked Questions (FAQ) for <H1>Developer's Frequently Asked Questions (FAQ) for
PostgreSQL</H1> PostgreSQL</H1>
<P>Last updated: Tue Nov 5 16:52:46 EST 2002</P> <P>Last updated: Fri Feb 14 08:59:10 EST 2003</P>
<P>Current maintainer: Bruce Momjian (<A href= <P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR> "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
@ -779,10 +779,8 @@
<DT>lconsi, ...</DT> <DT>lconsi, ...</DT>
<DD>There are integer versions of these: <I>lconsi, lappendi, <DD>There are integer versions of these: <I>lconsi, lappendi</I>,
nthi.</I> <I>List's</I> containing integers instead of Node etc. Also versions for OID lists: <I>lconso, lappendo</I>, etc.</DD>
pointers are used to hold list of relation object id's and
other integer quantities.</DD>
</DL> </DL>
</BLOCKQUOTE> </BLOCKQUOTE>
You can print nodes easily inside <I>gdb.</I> First, to disable You can print nodes easily inside <I>gdb.</I> First, to disable

44
doc/src/FAQ/FAQ_russian.html
View File

@ -13,7 +13,7 @@
alink="#0000ff"> alink="#0000ff">
<H1>Ответы на часто задаваемые вопросы по PostgreSQL</H1> <H1>Ответы на часто задаваемые вопросы по PostgreSQL</H1>
<P>Дата последнего обновления: Четверг 5 Декабря 00:47:26 EDT 2002</P> <P>Дата последнего обновления: Четверг 13 Февраля 23:07:35 EDT 2002</P>
<P>Английский вариант сопровождает: Брюс Момьян (Bruce Momjian) (<A href= <P>Английский вариант сопровождает: Брюс Момьян (Bruce Momjian) (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR> "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
@ -323,7 +323,7 @@
<H4><A name="1.7">1.7</A>) Какая последняя версия?</H4> <H4><A name="1.7">1.7</A>) Какая последняя версия?</H4>
<P>Последний выпуск PostgreSQL - это версия 7.2.3.</P> <P>Последний выпуск PostgreSQL - это версия 7.3.1.</P>
<P>Мы планируем выпускать новые версии каждые четыре месяца.</P> <P>Мы планируем выпускать новые версии каждые четыре месяца.</P>
@ -550,7 +550,7 @@
пользователя?</H4> пользователя?</H4>
<P>Да, существует несколько графических интерфейсов для PostgreSQL. <P>Да, существует несколько графических интерфейсов для PostgreSQL.
Это PgAccess (<A href="http://www.pgaccess.com/">http://www.pgaccess.com</A>, Это 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>, PgAdmin II (<A href="http://www.pgadmin.org/">http://www.pgadmin.org</A>,
Win32-only), RHDB Admin (<A href="http://sources.redhat.com/rhdb/"> Win32-only), RHDB Admin (<A href="http://sources.redhat.com/rhdb/">
http://sources.redhat.com/rhdb/</A>) и Rekall http://sources.redhat.com/rhdb/</A>) и Rekall
@ -558,11 +558,7 @@
http://www.thekompany.com/products/rekall/</A>, коммерческий). Также есть http://www.thekompany.com/products/rekall/</A>, коммерческий). Также есть
PHPPgAdmin (<A href="http://phppgadmin.sourceforge.net/"> PHPPgAdmin (<A href="http://phppgadmin.sourceforge.net/">
http://phppgadmin.sourceforge.net/</A>) - интерфейс к PostgreSQL, основанный http://phppgadmin.sourceforge.net/</A>) - интерфейс к PostgreSQL, основанный
на Web. на Web.</p>
<P>У нас есть прекрасный горафический интерфейс, называемый
PgAccess, который также можно использовать как генератор отчетов.
Его страничка <A href="http://www.pgaccess.org">http://www.pgaccess.org/</A></P>
<H4><A name="2.4">2.4</A>) Какие языки могут взаимодействовать с PostgreSQL?</H4> <H4><A name="2.4">2.4</A>) Какие языки могут взаимодействовать с PostgreSQL?</H4>
@ -772,10 +768,6 @@
Причина создания ограничения на количество backend процессов как Причина создания ограничения на количество backend процессов как
раз и состоит в том, чтобы вашей системе хватило ресурсов.</P> раз и состоит в том, чтобы вашей системе хватило ресурсов.</P>
<P>В PostgreSQL до версии 6.5, максимальное количество backend процессов
было 64, и изменение этого количества требовало перекомпиляции после
установки константы MaxBackendId в <I>include/storage/sinvaladt.h</I>.</P>
<H4><A name="3.9">3.9</A>) Что находится в каталоге <I>pgsql_tmp</I>?</H4> <H4><A name="3.9">3.9</A>) Что находится в каталоге <I>pgsql_tmp</I>?</H4>
<P>Данный каталог содержит временные файлы, генерируемые обработчиком <P>Данный каталог содержит временные файлы, генерируемые обработчиком
@ -969,6 +961,11 @@
LIMIT 1; LIMIT 1;
</pre> </pre>
<P>Если вам кажется, что оптимизатор некорретно выбирает последовательный
перебор, используйте <CODE>SET enable_seqscan TO 'off'</CODE> и
запустите тесты, чтобы увидеть, не стало-ли сканирование индексов быстрее.
</P>
<P>Когда используются операции с шаблонами, например <SMALL>LIKE</SMALL> <P>Когда используются операции с шаблонами, например <SMALL>LIKE</SMALL>
или <I>~</I>, индексы могут быть использованы в следующих случаях:</P> или <I>~</I>, индексы могут быть использованы в следующих случаях:</P>
<UL> <UL>
@ -1058,10 +1055,10 @@
<PRE> <PRE>
Тип Внутреннее имя Замечания Тип Внутреннее имя Замечания
-------------------------------------------------- --------------------------------------------------
"char" char 1 символ
CHAR(n) bpchar заполняется пустотой до фиксированной длины
VARCHAR(n) varchar размер задает максимальную длину, нет заполнения VARCHAR(n) varchar размер задает максимальную длину, нет заполнения
CHAR(n) bpchar заполняется пустотой до фиксированной длины
TEXT text нет задаваемого верхнего ограничения или длины TEXT text нет задаваемого верхнего ограничения или длины
"char" char один символ
BYTEA bytea массив байт переменной длины (можно использовать null-байт без опаски) BYTEA bytea массив байт переменной длины (можно использовать null-байт без опаски)
</PRE> </PRE>
@ -1076,13 +1073,16 @@ BYTEA bytea
так что занимаемое дисковое пространство может также быть и меньше, так что занимаемое дисковое пространство может также быть и меньше,
чем ожидалось.</P> чем ожидалось.</P>
<SMALL>VARCHAR(n)</SMALL> - это лучшее решение, когда нужно хранить
строки переменной длины, не превышающие определенного размера.
<SMALL>TEXT</SMALL> - это лучшее решение для строк неограниченной длины,
с максимально допустимой длиной в 1 гигабайт.
<P><SMALL>CHAR(n)</SMALL> - это лучшее решение для хранения строк, которые <P><SMALL>CHAR(n)</SMALL> - это лучшее решение для хранения строк, которые
обычно имеют одинаковую длину. <SMALL>VARCHAR(n)</SMALL> - это лучшее обычно имеют одинаковую длину. <SMALL>CHAR(n)</SMALL> заполняется
решение, когда нужно хранить строки переменной длины, но не превышающие пустотой до заданной длины, в то время как <SMALL>VARCHAR(n)</SMALL>
определенного размера. <SMALL>TEXT</SMALL> - это лучшее решение для строк хранит только символы, из которых состоит строка.
неограниченной длины, с максимально допустимой длиной в 1 гигабайт. <SMALL>BYTEA</SMALL> используется для хранения бинарных данных, значения
<SMALL>BYTEA</SMALL> для хранения бинарных данных, значения которых которых могут включать <SMALL>NULL</SMALL> байты. Эти типы имеют сходные
могут включать <SMALL>NULL</SMALL> байты. Эти типы имеют сходные
характеристики производительности.</P> характеристики производительности.</P>
<H4><A name="4.15.1">4.15.1</A>) Как мне создать поле <H4><A name="4.15.1">4.15.1</A>) Как мне создать поле
@ -1321,8 +1321,8 @@ BYTEA bytea
</PRE> </PRE>
Чтобы такая конструкция работала быстро, колонка <CODE>subcol</CODE> Чтобы такая конструкция работала быстро, колонка <CODE>subcol</CODE>
должна быть проиндексирована. должна быть проиндексирована. Эта проблема производительности будет
Мы надеемся убрать это ограничение в будущем выпуске. устранена в версии 7.4.
<H4><A name="4.23">4.23</A>) Как мне выполнить внешнее связывание?</H4> <H4><A name="4.23">4.23</A>) Как мне выполнить внешнее связывание?</H4>