aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorBruce Momjian <bruce@momjian.us>2002-10-14 03:15:33 +0000
committerBruce Momjian <bruce@momjian.us>2002-10-14 03:15:33 +0000
commitdaaf999fcbfaab378e4ac2800d26cc04f12f1500 (patch)
treeecf115834627b2f5f6e806437ff7ff3e6b6924d0
parent0896707ef612d69263838551ee9af526235f50dd (diff)
downloadpostgresql-daaf999fcbfaab378e4ac2800d26cc04f12f1500.tar.gz
postgresql-daaf999fcbfaab378e4ac2800d26cc04f12f1500.zip
Improvements to Ian Barwick patch.
-rw-r--r--doc/FAQ36
-rw-r--r--doc/src/FAQ/FAQ.html59
2 files changed, 49 insertions, 46 deletions
diff --git a/doc/FAQ b/doc/FAQ
index 9092c0a49af..56d907042dd 100644
--- a/doc/FAQ
+++ b/doc/FAQ
@@ -1,7 +1,7 @@
Frequently Asked Questions (FAQ) for PostgreSQL
- Last updated: Sun Oct 13 22:49:56 EDT 2002
+ Last updated: Sun Oct 13 23:15:09 EDT 2002
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
@@ -52,7 +52,7 @@
3.6) How do I tune the database engine for better performance?
3.7) What debugging features are available?
3.8) Why do I get "Sorry, too many clients" when trying to connect?
- 3.9) What are the pg_sorttempNNN.NN files in my database directory?
+ 3.9) What is in the pgsql_tmp directory?
3.10) Why do I need to do a dump and restore to upgrade PostgreSQL
releases?
@@ -197,8 +197,7 @@
distribution or the MS Windows FAQ at
http://www.PostgreSQL.org/docs/faq-mswin.html.
- A native port to some Microsoft platforms is currently being worked
- upon.
+ A native port to MS Win NT/2000/XP is currently being worked on.
1.5) Where can I get PostgreSQL?
@@ -368,7 +367,7 @@
1.15) How can I financially assist PostgreSQL?
PostgreSQL has had a first-class infrastructure since we started in
- 1994. This is all thanks to Marc Fournier, who has created and managed
+ 1996. This is all thanks to Marc Fournier, who has created and managed
this infrastructure over the years.
Quality infrastructure is very important to an open-source project. It
@@ -419,9 +418,9 @@
2.3) Does PostgreSQL have a graphical user interface? A report generator?
An embedded query language interface?
- We have a nice graphical user interface called PgAccess, which is
- shipped as part of the distribution. PgAccess also has a report
- generator. The Web page is http://www.pgaccess.org/.
+ 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/.
We also include ecpg, which is an embedded SQL query language
interface for C.
@@ -433,7 +432,7 @@
* C++ (libpq++)
* Embedded C (ecpg)
* Java (jdbc)
- * Perl (DBD::Pg)
+ * Perl (DBD::Pg and perl5)
* ODBC (odbc)
* Python (PyGreSQL)
* TCL (libpgtcl)
@@ -441,7 +440,8 @@
* PHP ('pg_' functions, Pear::DB)
Additional interfaces are available at
- http://www.PostgreSQL.org/interfaces.html.
+ http://www.PostgreSQL.org/interfaces.html and
+ http://gborg.PostgreSQL.org.
_________________________________________________________________
Administrative Questions
@@ -596,16 +596,16 @@
was 64, and changing it required a rebuild after altering the
MaxBackendId constant in include/storage/sinvaladt.h.
- 3.9) What are the pg_tempNNN.NN files in my database directory?
+ 3.9) What are the pgsql_tmp directory?
They are temporary files generated by the query executor. For example,
if a sort needs to be done to satisfy an ORDER BY, and the sort
requires more space than the backend's -S parameter allows, then
temporary files are created to hold the extra data.
- The temporary files should be deleted automatically, but might not if
- a backend crashes during a sort. If you have no backends running at
- the time, it is safe to delete the pg_tempNNN.NN files.
+ The temporary files are usually deleted automatically, but might
+ remain if a backend crashes during a sort. A stop and restart of the
+ postmaster will remove files from those directories.
3.10) Why do I need to do a dump and restore to upgrade between major
PostgreSQL releases?
@@ -649,8 +649,8 @@
4.4) How do you remove a column from a table?
- Prior to version 7.3, ALTER TABLE DROP COLUMN is not supported. You
- can do this instead:
+ This functionality was added in release 7.3 with ALTER TABLE DROP
+ COLUMN. In earlier versions, you can do this:
BEGIN;
LOCK TABLE old_table;
SELECT ... -- select all columns but the one you want to remove
@@ -815,11 +815,11 @@
Case-insensitive equality comparisons are normally expressed as:
SELECT *
FROM tab
- WHERE LOWER(col) = 'abc';
+ WHERE lower(col) = 'abc';
This will not use an standard index. However, if you create a
functional index, it will be used:
- CREATE INDEX tabindex ON tab (LOWER(col));
+ CREATE INDEX tabindex ON tab (lower(col));
4.13) In a query, how do I detect if a field is NULL?
diff --git a/doc/src/FAQ/FAQ.html b/doc/src/FAQ/FAQ.html
index 042a4984ee4..b8b24ccae02 100644
--- a/doc/src/FAQ/FAQ.html
+++ b/doc/src/FAQ/FAQ.html
@@ -14,7 +14,7 @@
alink="#0000ff">
<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
- <P>Last updated: Sun Oct 13 22:49:56 EDT 2002</P>
+ <P>Last updated: Sun Oct 13 23:15:09 EDT 2002</P>
<P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
@@ -78,8 +78,8 @@
<A href="#3.7">3.7</A>) What debugging features are available?<BR>
<A href="#3.8">3.8</A>) Why do I get <I>"Sorry, too many
clients"</I> when trying to connect?<BR>
- <A href="#3.9">3.9</A>) What are the <I>pg_sorttempNNN.NN</I>
- files in my database directory?<BR>
+ <A href="#3.9">3.9</A>) What is in the <I>pgsql_tmp</I>
+ directory?<BR>
<A href="#3.10">3.10</A>) Why do I need to do a dump and restore
to upgrade PostgreSQL releases?<BR>
@@ -250,10 +250,11 @@
<P>The database server can run on Windows NT and Win2k using
Cygwin, the Cygnus Unix/NT porting library. See
<I>pgsql/doc/FAQ_MSWIN</I> in the distribution or the MS Windows FAQ
- at <A href="http://www.PostgreSQL.org/docs/faq-mswin.html">http://www.PostgreSQL.org/docs/faq-mswin.html</A>.</P>
+ at <A href="http://www.PostgreSQL.org/docs/faq-mswin.html">
+ http://www.PostgreSQL.org/docs/faq-mswin.html</A>.</P>
- <p>A native port to some Microsoft platforms is currently being worked
- upon.</p>
+ <p>A native port to MS Win NT/2000/XP is currently being worked
+ on.</p>
<H4><A name="1.5">1.5</A>) Where can I get PostgreSQL?</H4>
@@ -484,7 +485,7 @@
PostgreSQL?</H4>
<P>PostgreSQL has had a first-class infrastructure since we started
- in 1994. This is all thanks to Marc Fournier, who has created
+ in 1996. This is all thanks to Marc Fournier, who has created
and managed this infrastructure over the years.</P>
<P>Quality infrastructure is very important to an open-source
@@ -545,9 +546,9 @@
interface? A report generator? An embedded query language
interface?</H4>
- <P>We have a nice graphical user interface called PgAccess, which is
- shipped as part of the distribution. PgAccess also has a report
- generator. The Web page is <A href="http://www.pgaccess.org/">http://www.pgaccess.org/</A>.</P>
+ <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>
<P>We also include <I>ecpg</I>, which is an embedded SQL query
language interface for C.</P>
@@ -565,7 +566,7 @@
<LI>Java (jdbc)</LI>
- <LI>Perl (DBD::Pg)</LI>
+ <LI>Perl (DBD::Pg and perl5)</LI>
<LI>ODBC (odbc)</LI>
@@ -578,7 +579,9 @@
<LI>PHP ('pg_' functions, Pear::DB)</LI>
</UL>
<P>Additional interfaces are available at
- <a href="http://www.PostgreSQL.org/interfaces.html">http://www.PostgreSQL.org/interfaces.html</A>.
+ <a href="http://www.PostgreSQL.org/interfaces.html">http://www.PostgreSQL.org/interfaces.html</A>
+ and
+ <a href="http://gborg.PostgreSQL.org">http://gborg.PostgreSQL.org</A>.
</P>
<HR>
@@ -765,8 +768,8 @@
the MaxBackendId constant in
<I>include/storage/sinvaladt.h</I>.</P>
- <H4><A name="3.9">3.9</A>) What are the <I>pg_tempNNN.NN</I>
- files in my database directory?</H4>
+ <H4><A name="3.9">3.9</A>) What are the <I>pgsql_tmp</I>
+ directory?</H4>
<P>They are temporary files generated by the query executor. For
example, if a sort needs to be done to satisfy an <SMALL>ORDER
@@ -774,10 +777,9 @@
<I>-S</I> parameter allows, then temporary files are created to
hold the extra data.</P>
- <P>The temporary files should be deleted automatically, but might
- not if a backend crashes during a sort. If you have no backends
- running at the time, it is safe to delete the pg_tempNNN.NN
- files.</P>
+ <P>The temporary files are usually deleted automatically, but might
+ remain if a backend crashes during a sort. A stop and restart of the
+ <I>postmaster</I> will remove files from those directories.</P>
<H4><A name="3.10">3.10</A>) Why do I need to do a dump and restore
to upgrade between major PostgreSQL releases?</H4>
@@ -790,10 +792,10 @@
data in a generic format that can then be loaded in using the new internal
format.</P>
- <p>In releases where the on-disk format does not change, the
- <i>pg_upgrade</i> script can be used to upgrade without a dump/restore.
- The release notes mention whether <i>pg_upgrade</i> is available for the
- release.</p>
+ <P>In releases where the on-disk format does not change, the
+ <I>pg_upgrade</I> script can be used to upgrade without a dump/restore.
+ The release notes mention whether <I>pg_upgrade</I> is available for the
+ release.</P>
<HR>
@@ -831,8 +833,9 @@
<H4><A name="4.4">4.4</A>) How do you remove a column from a
table?</H4>
- <P>Prior to version 7.3, <SMALL>ALTER TABLE DROP COLUMN</SMALL> is not supported.
- You can do this instead:</P>
+ <P>This functionality was added in release 7.3 with
+ <SMALL>ALTER TABLE DROP COLUMN</SMALL>. In earlier versions,
+ you can do this:</P>
<PRE>
BEGIN;
LOCK TABLE old_table;
@@ -1023,13 +1026,13 @@
<PRE>
SELECT *
FROM tab
- WHERE LOWER(col) = 'abc';
+ WHERE lower(col) = 'abc';
</PRE>
This will not use an standard index. However, if you create a
functional index, it will be used:
<PRE>
- CREATE INDEX tabindex ON tab (LOWER(col));
+ CREATE INDEX tabindex ON tab (lower(col));
</PRE>
<H4><A name="4.13">4.13</A>) In a query, how do I detect if a field
@@ -1118,7 +1121,7 @@ BYTEA bytea variable-length byte array (null-byte safe)
and your <SMALL>SERIAL</SMALL> column, respectively.
<P>Alternatively, you could retrieve the assigned
- <SMALL>SERIAL</SMALL> value with the <I>currval</I>() function
+ <SMALL>SERIAL</SMALL> value with the <I>currval()</I> function
<I>after</I> it was inserted by default, e.g.,</P>
<PRE>
execute("INSERT INTO person (name) VALUES ('Blaise Pascal')");
@@ -1135,7 +1138,7 @@ BYTEA bytea variable-length byte array (null-byte safe)
<H4><A name="4.15.3">4.15.3</A>) Don't <I>currval()</I> and
<I>nextval()</I> lead to a race condition with other users?</H4>
- <P>No. <i>currval</i>() returns the current value assigned by your
+ <P>No. <I>currval()</I> returns the current value assigned by your
backend, not by all users.</P>
<H4><A name="4.15.4">4.15.4</A>) Why aren't my sequence numbers