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Brand 7.2.3.

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This commit is contained in:
Bruce Momjian
2002-10-01 03:34:29 +00:00
parent 9227bc5e5b
commit 4526d2183f
9 changed files with 235 additions and 111 deletions
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2
configure vendored
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@@ -615,7 +615,7 @@ ac_config_sub=$ac_aux_dir/config.sub
ac_configure=$ac_aux_dir/configure # This should be Cygnus configure. ac_configure=$ac_aux_dir/configure # This should be Cygnus configure.
VERSION='7.2.2' VERSION='7.2.3'
cat >> confdefs.h <<EOF cat >> confdefs.h <<EOF
#define PG_VERSION "$VERSION" #define PG_VERSION "$VERSION"

2
configure.in
View File

@@ -28,7 +28,7 @@ AC_CONFIG_HEADER(src/include/pg_config.h)
AC_PREREQ(2.13) AC_PREREQ(2.13)
AC_CONFIG_AUX_DIR(config) AC_CONFIG_AUX_DIR(config)
VERSION='7.2.2' VERSION='7.2.3'
AC_SUBST(VERSION) AC_SUBST(VERSION)
AC_DEFINE_UNQUOTED(PG_VERSION, "$VERSION") AC_DEFINE_UNQUOTED(PG_VERSION, "$VERSION")

142
doc/FAQ
View File

@@ -1,7 +1,7 @@
Frequently Asked Questions (FAQ) for PostgreSQL Frequently Asked Questions (FAQ) for PostgreSQL
Last updated: Mon Mar 18 14:34:57 EST 2002 Last updated: Mon Sep 30 23:28:35 EDT 2002
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
@@ -53,6 +53,8 @@
3.7) What debugging features are available? 3.7) What debugging features are available?
3.8) Why do I get "Sorry, too many clients" when trying to connect? 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 are the pg_sorttempNNN.NN files in my database directory?
3.10) Why do I need to do a dump and restore to upgrade PostgreSQL
releases?
Operational Questions Operational Questions
@@ -63,8 +65,8 @@
4.5) What is the maximum size for a row, a table, and a database? 4.5) What is the maximum size for a row, a table, and a database?
4.6) How much database disk space is required to store data from a 4.6) How much database disk space is required to store data from a
typical text file? typical text file?
4.7) How do I find out what tables or indexes are defined in the 4.7) How do I find out what tables, indexes, databases, and users are
database? defined?
4.8) My queries are slow or don't make use of the indexes. Why? 4.8) My queries are slow or don't make use of the indexes. Why?
4.9) How do I see how the query optimizer is evaluating my query? 4.9) How do I see how the query optimizer is evaluating my query?
4.10) What is an R-tree index? 4.10) What is an R-tree index?
@@ -91,6 +93,9 @@
4.22) Why are my subqueries using IN so slow? 4.22) Why are my subqueries using IN so slow?
4.23) How do I perform an outer join? 4.23) How do I perform an outer join?
4.24) How do I perform queries using multiple databases? 4.24) How do I perform queries using multiple databases?
4.25) How do I return multiple rows or columns from a function?
4.26) Why can't I reliably create/drop temporary tables in PL/PgSQL
functions?
Extending PostgreSQL Extending PostgreSQL
@@ -237,7 +242,7 @@
1.7) What is the latest release? 1.7) What is the latest release?
The latest release of PostgreSQL is version 7.2.1. The latest release of PostgreSQL is version 7.2.3.
We plan to have major releases every four months. We plan to have major releases every four months.
@@ -320,29 +325,15 @@
reduce lock contention. reduce lock contention.
Performance Performance
PostgreSQL runs in two modes. Normal fsync mode flushes every PostgreSQL has performance similar to other commercial and open
completed transaction to disk, guaranteeing that if the OS source databases. it is faster for some things, slower for
crashes or loses power in the next few seconds, all your data others. In comparison to MySQL or leaner database systems, we
is safely stored on disk. In this mode, we are slower than most are slower on inserts/updates because of transaction overhead.
commercial databases, partly because few of them do such
conservative flushing to disk in their default modes. In
no-fsync mode, we are usually faster than commercial databases,
though in this mode, an OS crash could cause data corruption.
We are working to provide an intermediate mode that suffers
less performance overhead than full fsync mode, and will allow
data integrity within 30 seconds of an OS crash.
In comparison to MySQL or leaner database systems, we are
slower on inserts/updates because we have transaction overhead.
Of course, MySQL does not have any of the features mentioned in Of course, MySQL does not have any of the features mentioned in
the Features section above. We are built for flexibility and the Features section above. We are built for reliability and
features, though we continue to improve performance through features, though we continue to improve performance in every
profiling and source code analysis. There is an interesting Web release. There is an interesting Web page comparing PostgreSQL
page comparing PostgreSQL to MySQL at to MySQL at http://openacs.org/why-not-mysql.html
http://openacs.org/why-not-mysql.html
We handle each user connection by creating a Unix process.
Backend processes share data buffers and locking information.
With multiple CPUs, multiple backends can easily run on
different CPUs.
Reliability Reliability
We realize that a DBMS must be reliable, or it is worthless. We We realize that a DBMS must be reliable, or it is worthless. We
@@ -380,7 +371,8 @@
Of course, this infrastructure is not cheap. There are a variety of Of course, this infrastructure is not cheap. There are a variety of
monthly and one-time expenses that are required to keep it going. If monthly and one-time expenses that are required to keep it going. If
you or your company has money it can donate to help fund this effort, you or your company has money it can donate to help fund this effort,
please go to http://www.pgsql.com/pg_goodies and make a donation. please go to https://store.pgsql.com/shopping/index.php?id=1 and make
a donation.
Although the web page mentions PostgreSQL, Inc, the "contributions" Although the web page mentions PostgreSQL, Inc, the "contributions"
item is solely to support the PostgreSQL project and does not fund any item is solely to support the PostgreSQL project and does not fund any
@@ -443,6 +435,9 @@
* TCL (libpgtcl) * TCL (libpgtcl)
* C Easy API (libpgeasy) * C Easy API (libpgeasy)
* Embedded HTML (PHP from http://www.php.net) * Embedded HTML (PHP from http://www.php.net)
Additional interfaces are available at
http://www.postgresql.org/interfaces.html.
_________________________________________________________________ _________________________________________________________________
Administrative Questions Administrative Questions
@@ -570,7 +565,8 @@
You can also compile with profiling to see what functions are taking You can also compile with profiling to see what functions are taking
execution time. The backend profile files will be deposited in the execution time. The backend profile files will be deposited in the
pgsql/data/base/dbname directory. The client profile file will be put pgsql/data/base/dbname directory. The client profile file will be put
in the client's current directory. in the client's current directory. Linux requires a compile with
-DLINUX_PROFILE for proper profiling.
3.8) Why do I get "Sorry, too many clients" when trying to connect? 3.8) Why do I get "Sorry, too many clients" when trying to connect?
@@ -606,6 +602,21 @@
The temporary files should be deleted automatically, but might not if The temporary files should be deleted automatically, but might not if
a backend crashes during a sort. If you have no backends running at 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 time, it is safe to delete the pg_tempNNN.NN files.
3.10) Why do I need to do a dump and restore to upgrade between major
PostgreSQL releases?
The PostgreSQL team makes only small changes between minor releases,
so upgrading from 7.2 to 7.2.1 does not require a dump and restore.
However, major releases often change the internal format of system
tables and data files. These changes are often complex, so we don't
maintain backward compatability for data files. A dump outputs data in
a generic format that can then be loaded in using the new internal
format.
In releases where the on-disk format does not change, the pg_upgrade
script can be used to upgrade without a dump/restore. The release
notes mention whether pg_upgrade is available for the release.
_________________________________________________________________ _________________________________________________________________
Operational Questions Operational Questions
@@ -635,19 +646,22 @@
4.4) How do you remove a column from a table? 4.4) How do you remove a column from a table?
We do not support ALTER TABLE DROP COLUMN, but do this: We do not support ALTER TABLE DROP COLUMN, but do this:
BEGIN;
LOCK TABLE old_table;
SELECT ... -- select all columns but the one you want to remove SELECT ... -- select all columns but the one you want to remove
INTO TABLE new_table INTO TABLE new_table
FROM old_table; FROM old_table;
DROP TABLE old_table; DROP TABLE old_table;
ALTER TABLE new_table RENAME TO old_table; ALTER TABLE new_table RENAME TO old_table;
COMMIT;
4.5) What is the maximum size for a row, a table, and a database? 4.5) What is the maximum size for a row, a table, and a database?
These are the limits: These are the limits:
Maximum size for a database? unlimited (500 GB databases exist) Maximum size for a database? unlimited (1 TB databases exist)
Maximum size for a table? 16 TB Maximum size for a table? 16 TB
Maximum size for a row? unlimited in 7.1 and later Maximum size for a row? 1.6TB
Maximum size for a field? 1 GB in 7.1 and later Maximum size for a field? 1 GB
Maximum number of rows in a table? unlimited Maximum number of rows in a table? unlimited
Maximum number of columns in a table? 250-1600 depending on column types Maximum number of columns in a table? 250-1600 depending on column types
Maximum number of indexes on a table? unlimited Maximum number of indexes on a table? unlimited
@@ -695,10 +709,14 @@
Indexes do not require as much overhead, but do contain the data that Indexes do not require as much overhead, but do contain the data that
is being indexed, so they can be large also. is being indexed, so they can be large also.
4.7) How do I find out what tables or indexes are defined in the database? NULLs are stored in bitmaps, so they use very little space.
4.7) How do I find out what tables, indexes, databases, and users are
defined?
psql has a variety of backslash commands to show such information. Use psql has a variety of backslash commands to show such information. Use
\? to see them. \? to see them. There are also system tables beginning with pg_ that
describe these too. Also, psql -l will list all databases.
Also try the file pgsql/src/tutorial/syscat.source. It illustrates Also try the file pgsql/src/tutorial/syscat.source. It illustrates
many of the SELECTs needed to get information from the database system many of the SELECTs needed to get information from the database system
@@ -709,7 +727,7 @@
Indexes are not automatically used by every query. Indexes are only Indexes are not automatically used by every query. Indexes are only
used if the table is larger than a minimum size, and the query selects used if the table is larger than a minimum size, and the query selects
only a small percentage of the rows in the table. This is because the only a small percentage of the rows in the table. This is because the
random disk access caused by an index scan is sometimes slower than a random disk access caused by an index scan can be slower than a
straight read through the table, or sequential scan. straight read through the table, or sequential scan.
To determine if an index should be used, PostgreSQL must have To determine if an index should be used, PostgreSQL must have
@@ -724,12 +742,29 @@
sequential scan followed by an explicit sort is usually faster than an sequential scan followed by an explicit sort is usually faster than an
index scan of a large table. index scan of a large table.
However, LIMIT combined with ORDER BY often will use an index because However, LIMIT combined with ORDER BY often will use an index because
only a small portion of the table is returned. only a small portion of the table is returned. In fact, though MAX()
and MIN() don't use indexes, it is possible to retrieve such values
using an index with ORDER BY and LIMIT:
SELECT col
FROM tab
ORDER BY col [ DESC ]
LIMIT 1
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 if the beginning of the search is anchored to the start of the used in certain circumstances:
string. Therefore, to use indexes, LIKE patterns must not start with * The beginning of the search string must be anchored to the start
%, and ~(regular expression) patterns must start with ^. of the string, i.e.:
* LIKE patterns must not start with %.
* ~ (regular expression) patterns must start with ^.
The search string can not start with a character class, e.g. [a-e].
Case-insensitive searches like ILIKE and ~* can not be used.
Instead, use functional indexes, which are described later in this
FAQ.
The default C local must be used during initdb.
4.9) How do I see how the query optimizer is evaluating my query? 4.9) How do I see how the query optimizer is evaluating my query?
@@ -770,7 +805,7 @@
The ~ operator does regular expression matching, and ~* does The ~ operator does regular expression matching, and ~* does
case-insensitive regular expression matching. The case-insensitive case-insensitive regular expression matching. The case-insensitive
variant of LIKE is called ILIKE in PostgreSQL 7.1 and later. variant of LIKE is called ILIKE.
Case-insensitive equality comparisons are normally expressed as: Case-insensitive equality comparisons are normally expressed as:
SELECT * SELECT *
@@ -923,10 +958,9 @@ BYTEA bytea variable-length byte array (null-byte safe)
4.18) Why do I get the error "ERROR: Memory exhausted in AllocSetAlloc()"? 4.18) Why do I get the error "ERROR: Memory exhausted in AllocSetAlloc()"?
If you are running a version older than 7.1, an upgrade may fix the You probably have run out of virtual memory on your system, or your
problem. Also it is possible you have run out of virtual memory on kernel has a low limit for certain resources. Try this before starting
your system, or your kernel has a low limit for certain resources. Try postmaster:
this before starting postmaster:
ulimit -d 262144 ulimit -d 262144
limit datasize 256m limit datasize 256m
@@ -979,8 +1013,8 @@ SELECT *
4.23) How do I perform an outer join? 4.23) How do I perform an outer join?
PostgreSQL 7.1 and later supports outer joins using the SQL standard PostgreSQL supports outer joins using the SQL standard syntax. Here
syntax. Here are two examples: are two examples:
SELECT * SELECT *
FROM t1 LEFT OUTER JOIN t2 ON (t1.col = t2.col); FROM t1 LEFT OUTER JOIN t2 ON (t1.col = t2.col);
@@ -1015,6 +1049,24 @@ SELECT *
Of course, a client can make simultaneous connections to different Of course, a client can make simultaneous connections to different
databases and merge the information that way. databases and merge the information that way.
4.25) How do I return multiple rows or columns from a function?
You can return result sets from PL/pgSQL functions using refcursors.
See
http://developer.postgresql.org/docs/postgres/plpgsql-cursors.html,
section 23.7.3.3.
4.26) Why can't I reliably create/drop temporary tables in PL/PgSQL
functions?
PL/PgSQL caches function contents, and an unfortunate side effect is
that if a PL/PgSQL function accesses a temporary table, and that table
is later dropped and recreated, and the function called again, the
function will fail because the cached function contents still point to
the old temporary table. The solution is to use EXECUTE for temporary
table access in PL/PgSQL. This will cause the query to be reparsed
every time.
_________________________________________________________________ _________________________________________________________________
Extending PostgreSQL Extending PostgreSQL

2
doc/bug.template
View File

@@ -27,7 +27,7 @@ System Configuration
Operating System (example: Linux 2.0.26 ELF) : Operating System (example: Linux 2.0.26 ELF) :
PostgreSQL version (example: PostgreSQL-7.2.2): PostgreSQL-7.2.2 PostgreSQL version (example: PostgreSQL-7.2.3): PostgreSQL-7.2.3
Compiler used (example: gcc 2.95.2) : Compiler used (example: gcc 2.95.2) :

174
doc/src/FAQ/FAQ.html
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@@ -14,7 +14,7 @@
alink="#0000ff"> alink="#0000ff">
<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1> <H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
<P>Last updated: Mon Mar 18 14:34:57 EST 2002</P> <P>Last updated: Mon Sep 30 23:28:35 EDT 2002</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>
@@ -81,6 +81,8 @@
clients"</I> when trying to connect?<BR> clients"</I> when trying to connect?<BR>
<A href="#3.9">3.9</A>) What are the <I>pg_sorttempNNN.NN</I> <A href="#3.9">3.9</A>) What are the <I>pg_sorttempNNN.NN</I>
files in my database directory?<BR> files in my database directory?<BR>
<A href="#3.10">3.10</A>) Why do I need to do a dump and restore
to upgrade PostgreSQL releases?<BR>
<H2 align="center">Operational Questions</H2> <H2 align="center">Operational Questions</H2>
@@ -96,8 +98,8 @@
table, and a database?<BR> table, and a database?<BR>
<A href="#4.6">4.6</A>) How much database disk space is required <A href="#4.6">4.6</A>) How much database disk space is required
to store data from a typical text file?<BR> to store data from a typical text file?<BR>
<A href="#4.7">4.7</A>) How do I find out what tables or indexes <A href="#4.7">4.7</A>) How do I find out what tables, indexes,
are defined in the database?<BR> databases, and users are defined?<BR>
<A href="#4.8">4.8</A>) My queries are slow or don't make use of <A href="#4.8">4.8</A>) My queries are slow or don't make use of
the indexes. Why?<BR> the indexes. Why?<BR>
<A href="#4.9">4.9</A>) How do I see how the query optimizer is <A href="#4.9">4.9</A>) How do I see how the query optimizer is
@@ -137,6 +139,10 @@
<A href="#4.23">4.23</A>) How do I perform an outer join?<BR> <A href="#4.23">4.23</A>) How do I perform an outer join?<BR>
<A href="#4.24">4.24</A>) How do I perform queries using multiple <A href="#4.24">4.24</A>) How do I perform queries using multiple
databases?<BR> databases?<BR>
<A href="#4.25">4.25</A>) How do I return multiple rows or columns
from a function?<BR>
<A href="#4.26">4.26</A>) Why can't I reliably create/drop
temporary tables in PL/PgSQL functions?<BR>
<H2 align="center">Extending PostgreSQL</H2> <H2 align="center">Extending PostgreSQL</H2>
@@ -276,6 +282,7 @@
subscribe subscribe
end end
</PRE> </PRE>
Digests are sent out to members of this list whenever the main list Digests are sent out to members of this list whenever the main list
has received around 30k of messages. has received around 30k of messages.
@@ -287,6 +294,7 @@
subscribe subscribe
end end
</PRE> </PRE>
There is also a developers discussion mailing list available. To There is also a developers discussion mailing list available. To
subscribe to this list, send email to <A href= subscribe to this list, send email to <A href=
"mailto:pgsql-hackers-request@PostgreSQL.org">pgsql-hackers-request@PostgreSQL.org</A> "mailto:pgsql-hackers-request@PostgreSQL.org">pgsql-hackers-request@PostgreSQL.org</A>
@@ -312,7 +320,7 @@
<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 7.2.1.</P> <P>The latest release of PostgreSQL is version 7.2.3.</P>
<P>We plan to have major releases every four months.</P> <P>We plan to have major releases every four months.</P>
@@ -421,32 +429,18 @@
<DT><B>Performance</B></DT> <DT><B>Performance</B></DT>
<DD>PostgreSQL runs in two modes. Normal <I>fsync</I> mode <DD>PostgreSQL has performance similar to other commercial and
flushes every completed transaction to disk, guaranteeing that if open source databases. it is faster for some things, slower for
the OS crashes or loses power in the next few seconds, all your others. In comparison to MySQL or leaner database systems, we are
data is safely stored on disk. In this mode, we are slower than slower on inserts/updates because of transaction overhead. Of
most commercial databases, partly because few of them do such
conservative flushing to disk in their default modes. In
<I>no-fsync</I> mode, we are usually faster than commercial
databases, though in this mode, an OS crash could cause data
corruption. We are working to provide an intermediate mode that
suffers less performance overhead than full fsync mode, and will
allow data integrity within 30 seconds of an OS crash.<BR>
<BR>
In comparison to MySQL or leaner database systems, we are slower
on inserts/updates because we have transaction overhead. Of
course, MySQL does not have any of the features mentioned in the course, MySQL does not have any of the features mentioned in the
<I>Features</I> section above. We are built for flexibility and <I>Features</I> section above. We are built for reliability and
features, though we continue to improve performance through features, though we continue to improve performance in every
profiling and source code analysis. There is an interesting Web release. There is an interesting Web page comparing PostgreSQL to
page comparing PostgreSQL to MySQL at <A href= MySQL at <A href= "http://openacs.org/why-not-mysql.html">
"http://openacs.org/why-not-mysql.html">http://openacs.org/why-not-mysql.html</A><BR>
http://openacs.org/why-not-mysql.html</A><BR>
<BR>
We handle each user connection by creating a Unix process.
Backend processes share data buffers and locking information.
With multiple CPUs, multiple backends can easily run on different
CPUs.<BR>
<BR> <BR>
</DD> </DD>
@@ -499,7 +493,8 @@
of monthly and one-time expenses that are required to keep it of monthly and one-time expenses that are required to keep it
going. If you or your company has money it can donate to help fund going. If you or your company has money it can donate to help fund
this effort, please go to <A href= this effort, please go to <A href=
"http://www.pgsql.com/pg_goodies">http://www.pgsql.com/pg_goodies</A> "https://store.pgsql.com/shopping/index.php?id=1">
https://store.pgsql.com/shopping/index.php?id=1</A>
and make a donation.</P> and make a donation.</P>
<P>Although the web page mentions PostgreSQL, Inc, the <P>Although the web page mentions PostgreSQL, Inc, the
@@ -588,6 +583,10 @@
<LI>Embedded <SMALL>HTML</SMALL> (<A href= <LI>Embedded <SMALL>HTML</SMALL> (<A href=
"http://www.php.net">PHP from http://www.php.net</A>)</LI> "http://www.php.net">PHP from http://www.php.net</A>)</LI>
</UL> </UL>
<P>Additional interfaces are available at <a
href="http://www.postgresql.org/interfaces.html">
http://www.postgresql.org/interfaces.html.</A>
</P>
<HR> <HR>
<H2 align="center">Administrative Questions</H2> <H2 align="center">Administrative Questions</H2>
@@ -740,7 +739,8 @@
<P>You can also compile with profiling to see what functions are <P>You can also compile with profiling to see what functions are
taking execution time. The backend profile files will be deposited taking execution time. The backend profile files will be deposited
in the <I>pgsql/data/base/dbname</I> directory. The client profile in the <I>pgsql/data/base/dbname</I> directory. The client profile
file will be put in the client's current directory.</P> file will be put in the client's current directory. Linux requires
a compile with <I>-DLINUX_PROFILE</I> for proper profiling.</P>
<H4><A name="3.8">3.8</A>) Why do I get <I>"Sorry, too many <H4><A name="3.8">3.8</A>) Why do I get <I>"Sorry, too many
clients"</I> when trying to connect?</H4> clients"</I> when trying to connect?</H4>
@@ -785,6 +785,23 @@
not if a backend crashes during a sort. If you have no backends 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 running at the time, it is safe to delete the pg_tempNNN.NN
files.</P> files.</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>
<P>The PostgreSQL team makes only small changes between minor releases,
so upgrading from 7.2 to 7.2.1 does not require a dump and restore.
However, major releases often change the internal format of system
tables and data files. These changes are often complex, so we don't
maintain backward compatability for data files. A dump outputs data
in a generic format that can then be loaded in using the new internal
format.
<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.
<HR> <HR>
<H2 align="center">Operational Questions</H2> <H2 align="center">Operational Questions</H2>
@@ -824,11 +841,14 @@
<P>We do not support <SMALL>ALTER TABLE DROP COLUMN,</SMALL> but do <P>We do not support <SMALL>ALTER TABLE DROP COLUMN,</SMALL> but do
this:</P> this:</P>
<PRE> <PRE>
BEGIN;
LOCK TABLE old_table;
SELECT ... -- select all columns but the one you want to remove SELECT ... -- select all columns but the one you want to remove
INTO TABLE new_table INTO TABLE new_table
FROM old_table; FROM old_table;
DROP TABLE old_table; DROP TABLE old_table;
ALTER TABLE new_table RENAME TO old_table; ALTER TABLE new_table RENAME TO old_table;
COMMIT;
</PRE> </PRE>
<H4><A name="4.5">4.5</A>) What is the maximum size for a row, a <H4><A name="4.5">4.5</A>) What is the maximum size for a row, a
@@ -836,14 +856,15 @@
<P>These are the limits:</P> <P>These are the limits:</P>
<PRE> <PRE>
Maximum size for a database? unlimited (500 GB databases exist) Maximum size for a database? unlimited (1 TB databases exist)
Maximum size for a table? 16 TB Maximum size for a table? 16 TB
Maximum size for a row? unlimited in 7.1 and later Maximum size for a row? 1.6TB
Maximum size for a field? 1 GB in 7.1 and later Maximum size for a field? 1 GB
Maximum number of rows in a table? unlimited Maximum number of rows in a table? unlimited
Maximum number of columns in a table? 250-1600 depending on column types Maximum number of columns in a table? 250-1600 depending on column types
Maximum number of indexes on a table? unlimited Maximum number of indexes on a table? unlimited
</PRE> </PRE>
Of course, these are not actually unlimited, but limited to Of course, these are not actually unlimited, but limited to
available disk space and memory/swap space. Performance may suffer available disk space and memory/swap space. Performance may suffer
when these values get unusually large. when these values get unusually large.
@@ -890,11 +911,16 @@
<P>Indexes do not require as much overhead, but do contain the data <P>Indexes do not require as much overhead, but do contain the data
that is being indexed, so they can be large also.</P> that is being indexed, so they can be large also.</P>
<H4><A name="4.7">4.7</A>) How do I find out what tables or indexes <P><SMALL>NULL</SMALL>s are stored in bitmaps, so they
are defined in the database?</H4> use very little space.</P>
<H4><A name="4.7">4.7</A>) How do I find out what tables, indexes,
databases, and users are defined?</H4>
<P><I>psql</I> has a variety of backslash commands to show such <P><I>psql</I> has a variety of backslash commands to show such
information. Use \? to see them.</P> information. Use \? to see them. There are also system tables
beginning with <I>pg_</I> that describe these too. Also, <I>psql
-l</I> will list all databases.</P>
<P>Also try the file <I>pgsql/src/tutorial/syscat.source</I>. It <P>Also try the file <I>pgsql/src/tutorial/syscat.source</I>. It
illustrates many of the <SMALL>SELECT</SMALL>s needed to get illustrates many of the <SMALL>SELECT</SMALL>s needed to get
@@ -905,7 +931,7 @@
Indexes are not automatically used by every query. Indexes are only Indexes are not automatically used by every query. Indexes are only
used if the table is larger than a minimum size, and the query used if the table is larger than a minimum size, and the query
selects only a small percentage of the rows in the table. This is selects only a small percentage of the rows in the table. This is
because the random disk access caused by an index scan is sometimes because the random disk access caused by an index scan can be
slower than a straight read through the table, or sequential scan. slower than a straight read through the table, or sequential scan.
<P>To determine if an index should be used, PostgreSQL must have <P>To determine if an index should be used, PostgreSQL must have
@@ -922,13 +948,35 @@
usually faster than an index scan of a large table.</P> usually faster than an index scan of a large table.</P>
However, <SMALL>LIMIT</SMALL> combined with <SMALL>ORDER BY</SMALL> However, <SMALL>LIMIT</SMALL> combined with <SMALL>ORDER BY</SMALL>
often will use an index because only a small portion of the table often will use an index because only a small portion of the table
is returned. is returned. In fact, though MAX() and MIN() don't use indexes,
it is possible to retrieve such values using an index with ORDER BY
and LIMIT:
<PRE>
SELECT col
FROM tab
ORDER BY col [ DESC ]
LIMIT 1
</PRE>
<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 if the beginning of the search <I>~</I>, indexes can only be used in certain circumstances:
is anchored to the start of the string. Therefore, to use indexes, <UL>
<SMALL>LIKE</SMALL> patterns must not start with <I>%</I>, and <LI>The beginning of the search string must be anchored to the start
<I>~</I>(regular expression) patterns must start with <I>^</I>.</P> of the string, i.e.:</LI>
<UL>
<LI><SMALL>LIKE</SMALL> patterns must not start with <I>%.</I></LI>
<LI><I>~</I> (regular expression) patterns must start with
<I>^.</I></LI>
</UL>
<LI>The search string can not start with a character class,
e.g. [a-e].</LI>
<LI>Case-insensitive searches like <SMALL>ILIKE</SMALL> and
<I>~*</I> can not be used. Instead, use functional
indexes, which are described later in this FAQ.</LI>
<LI>The default <I>C</I> local must be used during
<i>initdb.</i></LI>
</UL>
<P>
<H4><A name="4.9">4.9</A>) How do I see how the query optimizer is <H4><A name="4.9">4.9</A>) How do I see how the query optimizer is
evaluating my query?</H4> evaluating my query?</H4>
@@ -975,7 +1023,7 @@
<P>The <I>~</I> operator does regular expression matching, and <P>The <I>~</I> operator does regular expression matching, and
<I>~*</I> does case-insensitive regular expression matching. The <I>~*</I> does case-insensitive regular expression matching. The
case-insensitive variant of <SMALL>LIKE</SMALL> is called case-insensitive variant of <SMALL>LIKE</SMALL> is called
<SMALL>ILIKE</SMALL> in PostgreSQL 7.1 and later.</P> <SMALL>ILIKE</SMALL>.</P>
<P>Case-insensitive equality comparisons are normally expressed <P>Case-insensitive equality comparisons are normally expressed
as:</P> as:</P>
@@ -983,13 +1031,12 @@
SELECT * SELECT *
FROM tab FROM tab
WHERE lower(col) = 'abc' WHERE lower(col) = 'abc'
</PRE> </PRE>
This will not use an standard index. However, if you create a This will not use an standard index. However, if you create a
functional index, it will be used: functional index, it will be used:
<PRE> <PRE>
CREATE INDEX tabindex on tab (lower(col)); CREATE INDEX tabindex on tab (lower(col));
</PRE> </PRE>
<H4><A name="4.13">4.13</A>) In a query, how do I detect if a field <H4><A name="4.13">4.13</A>) In a query, how do I detect if a field
@@ -1039,6 +1086,7 @@ BYTEA bytea variable-length byte array (null-byte safe)
name TEXT name TEXT
); );
</PRE> </PRE>
is automatically translated into this: is automatically translated into this:
<PRE> <PRE>
CREATE SEQUENCE person_id_seq; CREATE SEQUENCE person_id_seq;
@@ -1048,6 +1096,7 @@ BYTEA bytea variable-length byte array (null-byte safe)
); );
CREATE UNIQUE INDEX person_id_key ON person ( id ); CREATE UNIQUE INDEX person_id_key ON person ( id );
</PRE> </PRE>
See the <I>create_sequence</I> manual page for more information See the <I>create_sequence</I> manual page for more information
about sequences. You can also use each row's <I>OID</I> field as a about sequences. You can also use each row's <I>OID</I> field as a
unique value. However, if you need to dump and reload the database, unique value. However, if you need to dump and reload the database,
@@ -1066,6 +1115,7 @@ BYTEA bytea variable-length byte array (null-byte safe)
new_id = output of "SELECT nextval('person_id_seq')" new_id = output of "SELECT nextval('person_id_seq')"
INSERT INTO person (id, name) VALUES (new_id, 'Blaise Pascal'); INSERT INTO person (id, name) VALUES (new_id, 'Blaise Pascal');
</PRE> </PRE>
You would then also have the new value stored in You would then also have the new value stored in
<CODE>new_id</CODE> for use in other queries (e.g., as a foreign <CODE>new_id</CODE> for use in other queries (e.g., as a foreign
key to the <CODE>person</CODE> table). Note that the name of the key to the <CODE>person</CODE> table). Note that the name of the
@@ -1081,6 +1131,7 @@ BYTEA bytea variable-length byte array (null-byte safe)
INSERT INTO person (name) VALUES ('Blaise Pascal'); INSERT INTO person (name) VALUES ('Blaise Pascal');
new_id = output of "SELECT currval('person_id_seq')"; new_id = output of "SELECT currval('person_id_seq')";
</PRE> </PRE>
Finally, you could use the <A href="#4.16"><SMALL>OID</SMALL></A> Finally, you could use the <A href="#4.16"><SMALL>OID</SMALL></A>
returned from the <SMALL>INSERT</SMALL> statement to look up the returned from the <SMALL>INSERT</SMALL> statement to look up the
default value, though this is probably the least portable approach. default value, though this is probably the least portable approach.
@@ -1180,14 +1231,14 @@ BYTEA bytea variable-length byte array (null-byte safe)
<H4><A name="4.18">4.18</A>) Why do I get the error <I>"ERROR: <H4><A name="4.18">4.18</A>) Why do I get the error <I>"ERROR:
Memory exhausted in AllocSetAlloc()"</I>?</H4> Memory exhausted in AllocSetAlloc()"</I>?</H4>
<P>If you are running a version older than 7.1, an upgrade may fix <P>You probably have run out of virtual memory on your system,
the problem. Also it is possible you have run out of virtual memory or your kernel has a low limit for certain resources. Try this
on your system, or your kernel has a low limit for certain before starting <I>postmaster</I>:</P>
resources. Try this before starting <I>postmaster</I>:</P>
<PRE> <PRE>
ulimit -d 262144 ulimit -d 262144
limit datasize 256m limit datasize 256m
</PRE> </PRE>
Depending on your shell, only one of these may succeed, but it will Depending on your shell, only one of these may succeed, but it will
set your process data segment limit much higher and perhaps allow set your process data segment limit much higher and perhaps allow
the query to complete. This command applies to the current process, the query to complete. This command applies to the current process,
@@ -1246,12 +1297,13 @@ BYTEA bytea variable-length byte array (null-byte safe)
WHERE EXISTS (SELECT col2 FROM TAB2 WHERE col1 = col2) WHERE EXISTS (SELECT col2 FROM TAB2 WHERE col1 = col2)
</CODE> </CODE>
</PRE> </PRE>
We hope to fix this limitation in a future release. We hope to fix this limitation in a future release.
<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>
<P>PostgreSQL 7.1 and later supports outer joins using the SQL <P>PostgreSQL supports outer joins using the SQL standard syntax.
standard syntax. Here are two examples:</P> Here are two examples:</P>
<PRE> <PRE>
SELECT * SELECT *
FROM t1 LEFT OUTER JOIN t2 ON (t1.col = t2.col); FROM t1 LEFT OUTER JOIN t2 ON (t1.col = t2.col);
@@ -1297,6 +1349,26 @@ BYTEA bytea variable-length byte array (null-byte safe)
<P>Of course, a client can make simultaneous connections to <P>Of course, a client can make simultaneous connections to
different databases and merge the information that way.</P> different databases and merge the information that way.</P>
<H4><A name="4.25">4.25</A>) How do I return multiple rows or
columns from a function?</H4>
<P>You can return result sets from PL/pgSQL functions using
<I>refcursors</I>. See <A href=
"http://developer.postgresql.org/docs/postgres/plpgsql-cursors.html">
http://developer.postgresql.org/docs/postgres/plpgsql-cursors.html,</A>
section 23.7.3.3.</P>
<H4><A name="4.26">4.26</A>) Why can't I reliably create/drop
temporary tables in PL/PgSQL functions?</H4>
PL/PgSQL caches function contents, and an unfortunate side effect
is that if a PL/PgSQL function accesses a temporary table, and that
table is later dropped and recreated, and the function called
again, the function will fail because the cached function contents
still point to the old temporary table. The solution is to use
<SMALL>EXECUTE</SMALL> for temporary table access in PL/PgSQL. This
will cause the query to be reparsed every time.
<HR> <HR>
<H2 align="center">Extending PostgreSQL</H2> <H2 align="center">Extending PostgreSQL</H2>

2
doc/src/sgml/version.sgml
View File

@@ -3,5 +3,5 @@ Update this file to propagate correct current version numbers to the
documentation. In text, use for example &version; to refer to them. documentation. In text, use for example &version; to refer to them.
--> -->
<!entity version "7.2.2"> <!entity version "7.2.3">
<!entity majorversion "7.2"> <!entity majorversion "7.2">

4
src/include/pg_config.h.win32
View File

@@ -3,8 +3,8 @@
/* /*
* Parts of pg_config.h that you get with autoconf on other systems * Parts of pg_config.h that you get with autoconf on other systems
*/ */
#define PG_VERSION "7.2.2" #define PG_VERSION "7.2.3"
#define PG_VERSION_STR "7.2.2 (win32)" #define PG_VERSION_STR "7.2.3 (win32)"
#define SYSCONFDIR "" #define SYSCONFDIR ""

8
src/interfaces/libpq++/libpq++dll.rc
View File

@@ -1,8 +1,8 @@
#include <winver.h> #include <winver.h>
VS_VERSION_INFO VERSIONINFO VS_VERSION_INFO VERSIONINFO
FILEVERSION 7,2,2,0 FILEVERSION 7,2,3,0
PRODUCTVERSION 7,2,2,0 PRODUCTVERSION 7,2,3,0
FILEFLAGSMASK 0x3fL FILEFLAGSMASK 0x3fL
FILEFLAGS 0x0L FILEFLAGS 0x0L
FILEOS 0x40004L FILEOS 0x40004L
@@ -16,14 +16,14 @@ BEGIN
VALUE "Comments", "\0" VALUE "Comments", "\0"
VALUE "CompanyName", " \0" VALUE "CompanyName", " \0"
VALUE "FileDescription", "PostgreSQL C++ Access Library\0" VALUE "FileDescription", "PostgreSQL C++ Access Library\0"
VALUE "FileVersion", "7, 2, 2, 0\0" VALUE "FileVersion", "7, 2, 3, 0\0"
VALUE "InternalName", "libpq++\0" VALUE "InternalName", "libpq++\0"
VALUE "LegalCopyright", "Copyright <20> 2000\0" VALUE "LegalCopyright", "Copyright <20> 2000\0"
VALUE "LegalTrademarks", "\0" VALUE "LegalTrademarks", "\0"
VALUE "OriginalFilename", "libpq++.dll\0" VALUE "OriginalFilename", "libpq++.dll\0"
VALUE "PrivateBuild", "\0" VALUE "PrivateBuild", "\0"
VALUE "ProductName", "PostgreSQL\0" VALUE "ProductName", "PostgreSQL\0"
VALUE "ProductVersion", "7, 2, 2, 0\0" VALUE "ProductVersion", "7, 2, 3, 0\0"
VALUE "SpecialBuild", "\0" VALUE "SpecialBuild", "\0"
END END
END END

8
src/interfaces/libpq/libpq.rc
View File

@@ -1,8 +1,8 @@
#include <winver.h> #include <winver.h>
VS_VERSION_INFO VERSIONINFO VS_VERSION_INFO VERSIONINFO
FILEVERSION 7,2,2,0 FILEVERSION 7,2,3,0
PRODUCTVERSION 7,2,2,0 PRODUCTVERSION 7,2,3,0
FILEFLAGSMASK 0x3fL FILEFLAGSMASK 0x3fL
FILEFLAGS 0 FILEFLAGS 0
FILEOS VOS__WINDOWS32 FILEOS VOS__WINDOWS32
@@ -15,13 +15,13 @@ BEGIN
BEGIN BEGIN
VALUE "CompanyName", "\0" VALUE "CompanyName", "\0"
VALUE "FileDescription", "PostgreSQL Access Library\0" VALUE "FileDescription", "PostgreSQL Access Library\0"
VALUE "FileVersion", "7, 2, 2, 0\0" VALUE "FileVersion", "7, 2, 3, 0\0"
VALUE "InternalName", "libpq\0" VALUE "InternalName", "libpq\0"
VALUE "LegalCopyright", "Copyright (C) 2000\0" VALUE "LegalCopyright", "Copyright (C) 2000\0"
VALUE "LegalTrademarks", "\0" VALUE "LegalTrademarks", "\0"
VALUE "OriginalFilename", "libpq.dll\0" VALUE "OriginalFilename", "libpq.dll\0"
VALUE "ProductName", "PostgreSQL\0" VALUE "ProductName", "PostgreSQL\0"
VALUE "ProductVersion", "7, 2, 2, 0\0" VALUE "ProductVersion", "7, 2, 3, 0\0"
END END
END END
BLOCK "VarFileInfo" BLOCK "VarFileInfo"