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postgresql/doc/src/sgml/catalogs.sgml

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Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<!--
Documentation of the system catalogs, directed toward PostgreSQL developers
This patch includes a lot of minor cleanups to the SGML documentation, including: - replacing all the appropriate usages of <citetitle>PostgreSQL ...</citetitle> with &cite-user;, &cite-admin;, and so on - fix an omission in the EXECUTE documentation - add some more text to the EXPLAIN documentation - improve the PL/PgSQL RETURN NEXT documentation (more work to do here) - minor markup fixes Neil Conway
2003-01-19 01:13:31 +01:00
$Header: /cvsroot/pgsql/doc/src/sgml/catalogs.sgml,v 2.65 2003/01/19 00:13:28 momjian Exp $
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
-->
<chapter id="catalogs">
<title>System Catalogs</title>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
<sect1 id="catalogs-overview">
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<title>Overview</title>
<para>
The system catalogs are the place where a relational database
management system stores schema metadata, such as information about
tables and columns, and internal bookkeeping information.
<productname>PostgreSQL</productname>'s system catalogs are regular
tables. You can drop and recreate the tables, add columns, insert
and update values, and severely mess up your system that way.
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
Normally one should not change the system catalogs by hand, there
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
are always SQL commands to do that. (For example, <command>CREATE
DATABASE</command> inserts a row into the
<structname>pg_database</structname> catalog -- and actually
creates the database on disk.) There are some exceptions for
Rewrite xindex.sgml for CREATE OPERATOR CLASS. catalogs.sgml finally contains descriptions of every single system table. Update 'complex' tutorial example too.
2002-07-30 07:24:56 +02:00
especially esoteric operations, such as adding index access methods.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</para>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<para>
Most system catalogs are copied from the template database during
database creation, and are thereafter database-specific. A few
catalogs are physically shared across all databases in an installation;
these are marked in the descriptions of the individual catalogs.
</para>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<table>
<title>System Catalogs</title>
<tgroup cols="2">
<thead>
<row>
<entry>Catalog Name</entry>
<entry>Purpose</entry>
</row>
</thead>
<tbody>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-aggregate">
<database class="table">pg_aggregate</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>aggregate functions</entry>
</row>
<row>
<entry>pg_am</entry>
<entry>index access methods</entry>
</row>
<row>
<entry>pg_amop</entry>
<entry>access method operators</entry>
</row>
<row>
<entry>pg_amproc</entry>
<entry>access method support procedures</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-attrdef">
<database class="table">pg_attrdef</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>column default values</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-attribute">
<database class="table">pg_attribute</database></link></entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<entry>table columns (<quote>attributes</quote>, <quote>fields</quote>)</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
Add unique index on pg_cast.oid, and document pg_cast table.
2002-07-22 22:23:19 +02:00
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-cast">
<database class="table">pg_cast</database></link></entry>
Add unique index on pg_cast.oid, and document pg_cast table.
2002-07-22 22:23:19 +02:00
<entry>casts (data type conversions)</entry>
</row>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-class">
<database class="table">pg_class</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>tables, indexes, sequences (<quote>relations</quote>)</entry>
</row>
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
2002-07-12 20:43:19 +02:00
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-constraint">
<database class="table">pg_constraint</database></link></entry>
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
2002-07-12 20:43:19 +02:00
<entry>check constraints, unique / primary key constraints, foreign key constraints</entry>
</row>
Add pg_conversion system catalog. Update description for multibyte support.
2002-07-24 07:51:56 +02:00
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-conversion">
<database class="table">pg_conversion</database></link></entry>
Add pg_conversion system catalog. Update description for multibyte support.
2002-07-24 07:51:56 +02:00
<entry>encoding conversion information</entry>
</row>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-database">
<database class="table">pg_database</database></link></entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<entry>databases within this database cluster</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
2002-07-12 20:43:19 +02:00
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-depend">
<database class="table">pg_depend</database></link></entry>
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
2002-07-12 20:43:19 +02:00
<entry>dependencies between database objects</entry>
</row>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-description">
<database class="table">pg_description</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>descriptions or comments on database objects</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-group">
<database class="table">pg_group</database></link></entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<entry>groups of database users</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-index">
<database class="table">pg_index</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>additional index information</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-inherits">
<database class="table">pg_inherits</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>table inheritance hierarchy</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-language">
<database class="table">pg_language</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>languages for writing functions</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-largeobject">
<database class="table">pg_largeobject</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>large objects</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-listener">
<database class="table">pg_listener</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>asynchronous notification</entry>
</row>
Create the pg_namespace system catalog. Doesn't do much yet, but it's there and CREATE SCHEMA will make entries in it...
2002-03-22 22:34:44 +01:00
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-namespace">
<database class="table">pg_namespace</database></link></entry>
Create the pg_namespace system catalog. Doesn't do much yet, but it's there and CREATE SCHEMA will make entries in it...
2002-03-22 22:34:44 +01:00
<entry>namespaces (schemas)</entry>
</row>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-opclass">
<database class="table">pg_opclass</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>index access method operator classes</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-operator">
<database class="table">pg_operator</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>operators</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-proc">
<database class="table">pg_proc</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>functions and procedures</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-rewrite">
<database class="table">pg_rewrite</database></link></entry>
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<entry>query rewriter rules</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-shadow">
<database class="table">pg_shadow</database></link></entry>
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<entry>database users</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-statistic">
<database class="table">pg_statistic</database></link></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
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<entry>optimizer statistics</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-trigger">
<database class="table">pg_trigger</database></link></entry>
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<entry>triggers</entry>
</row>
<row>
- Link the entries in the table to the catalog heading - Wrap them in the <database class="table"> tags, since thats what they are (no markup rules for this, so it inherits from parent -- no style change) - Mention that pg_database, pg_shadow, and pg_group are global, and the rest are local to the specific DB. (I believe this is correct). > Works for me, though I suppose we could explain what the exceptions are > like in general terms. Perhaps something like > > 'Most system catalogs are copied from the template database during > database creation, and are thereafter database-specific. A few > catalogs are physically shared across all databases in an installation; > these are marked in the descriptions of the individual catalogs.' Ok, new patch. Rod Taylor
2002-10-14 06:29:23 +02:00
<entry><link linkend="catalog-pg-type">
<database class="table">pg_type</database></link></entry>
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<entry>data types</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
Rewrite xindex.sgml for CREATE OPERATOR CLASS. catalogs.sgml finally contains descriptions of every single system table. Update 'complex' tutorial example too.
2002-07-30 07:24:56 +02:00
More detailed documentation of each catalog follows below.
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</para>
Use <sect1> rather than <section> to simplify formatting.
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</sect1>
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Use <sect1> rather than <section> to simplify formatting.
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<sect1 id="catalog-pg-aggregate">
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<title>pg_aggregate</title>
<para>
<structname>pg_aggregate</structname> stores information about
aggregate functions. An aggregate function is a function that
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
operates on a set of values (typically one column from each row
Rewrite system catalog documentation man page in DocBook with more recent information.
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that matches a query condition) and returns a single value computed
from all these values. Typical aggregate functions are
<function>sum</function>, <function>count</function>, and
Restructure representation of aggregate functions so that they have pg_proc entries, per pghackers discussion. This fixes aggregates to live in namespaces, and also simplifies/speeds up lookup in parse_func.c. Also, add a 'proimplicit' flag to pg_proc that controls whether a type coercion function may be invoked implicitly, or only explicitly. The current settings of these flags are more permissive than I would like, but we will need to debate and refine the behavior; for now, I avoided breaking regression tests as much as I could.
2002-04-11 22:00:18 +02:00
<function>max</function>. Each entry in
<structname>pg_aggregate</structname> is an extension of an entry
in <structname>pg_proc</structname>. The <structname>pg_proc</structname>
entry carries the aggregate's name, input and output datatypes, and
other information that is similar to ordinary functions.
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</para>
<table>
<title>pg_aggregate Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
Restructure representation of aggregate functions so that they have pg_proc entries, per pghackers discussion. This fixes aggregates to live in namespaces, and also simplifies/speeds up lookup in parse_func.c. Also, add a 'proimplicit' flag to pg_proc that controls whether a type coercion function may be invoked implicitly, or only explicitly. The current settings of these flags are more permissive than I would like, but we will need to debate and refine the behavior; for now, I avoided breaking regression tests as much as I could.
2002-04-11 22:00:18 +02:00
<entry>aggfnoid</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry>pg_proc OID of the aggregate function</entry>
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</row>
<row>
<entry>aggtransfn</entry>
Restructure representation of aggregate functions so that they have pg_proc entries, per pghackers discussion. This fixes aggregates to live in namespaces, and also simplifies/speeds up lookup in parse_func.c. Also, add a 'proimplicit' flag to pg_proc that controls whether a type coercion function may be invoked implicitly, or only explicitly. The current settings of these flags are more permissive than I would like, but we will need to debate and refine the behavior; for now, I avoided breaking regression tests as much as I could.
2002-04-11 22:00:18 +02:00
<entry><type>regproc</type></entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<entry>pg_proc.oid</entry>
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<entry>Transition function</entry>
</row>
<row>
<entry>aggfinalfn</entry>
Restructure representation of aggregate functions so that they have pg_proc entries, per pghackers discussion. This fixes aggregates to live in namespaces, and also simplifies/speeds up lookup in parse_func.c. Also, add a 'proimplicit' flag to pg_proc that controls whether a type coercion function may be invoked implicitly, or only explicitly. The current settings of these flags are more permissive than I would like, but we will need to debate and refine the behavior; for now, I avoided breaking regression tests as much as I could.
2002-04-11 22:00:18 +02:00
<entry><type>regproc</type></entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<entry>pg_proc.oid</entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<entry>Final function (zero if none)</entry>
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</row>
<row>
<entry>aggtranstype</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>The type of the aggregate function's internal transition (state) data</entry>
</row>
<row>
<entry>agginitval</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry>
The initial value of the transition state. This is a text
Fix handling of pg_type.typdefault per bug report from Dave Blasby. If there's anyone out there who's actually using datatype-defined default values, this will be an incompatible change in behavior ... but the old behavior was so broken that I doubt anyone was using it.
2001-09-06 04:07:42 +02:00
field containing the initial value in its external string
representation. If the field is NULL, the transition state
value starts out NULL.
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</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
New aggregate functions are registered with the <command>CREATE
This patch includes a lot of minor cleanups to the SGML documentation, including: - replacing all the appropriate usages of <citetitle>PostgreSQL ...</citetitle> with &cite-user;, &cite-admin;, and so on - fix an omission in the EXECUTE documentation - add some more text to the EXPLAIN documentation - improve the PL/PgSQL RETURN NEXT documentation (more work to do here) - minor markup fixes Neil Conway
2003-01-19 01:13:31 +01:00
AGGREGATE</command> command. See the &cite-programmer; for more
information about writing aggregate functions and the meaning of
the transition functions, etc.
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</para>
Use <sect1> rather than <section> to simplify formatting.
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</sect1>
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Rewrite xindex.sgml for CREATE OPERATOR CLASS. catalogs.sgml finally contains descriptions of every single system table. Update 'complex' tutorial example too.
2002-07-30 07:24:56 +02:00
<sect1 id="catalog-pg-am">
<title>pg_am</title>
<para>
<structname>pg_am</structname> stores information about index access
methods. There is one row for each index access method supported by
the system.
</para>
<table>
<title>pg_am Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>amname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>name of the access method</entry>
</row>
<row>
<entry>amowner</entry>
<entry><type>int4</type></entry>
<entry>pg_shadow.usesysid</entry>
<entry>user ID of the owner (currently not used)</entry>
</row>
<row>
<entry>amstrategies</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>number of operator strategies for this access method</entry>
</row>
<row>
<entry>amsupport</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>number of support routines for this access method</entry>
</row>
<row>
<entry>amorderstrategy</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>zero if the index offers no sort order, otherwise the strategy
number of the strategy operator that describes the sort order</entry>
</row>
<row>
<entry>amcanunique</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>does AM support unique indexes?</entry>
</row>
<row>
<entry>amcanmulticol</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>does AM support multicolumn indexes?</entry>
</row>
<row>
<entry>amindexnulls</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>does AM support NULL index entries?</entry>
</row>
<row>
<entry>amconcurrent</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>does AM support concurrent updates?</entry>
</row>
<row>
<entry>amgettuple</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry><quote>next valid tuple</quote> function</entry>
</row>
<row>
<entry>aminsert</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry><quote>insert this tuple</quote> function</entry>
</row>
<row>
<entry>ambeginscan</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry><quote>start new scan</quote> function</entry>
</row>
<row>
<entry>amrescan</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry><quote>restart this scan</quote> function</entry>
</row>
<row>
<entry>amendscan</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry><quote>end this scan</quote> function</entry>
</row>
<row>
<entry>ammarkpos</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry><quote>mark current scan position</quote> function</entry>
</row>
<row>
<entry>amrestrpos</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry><quote>restore marked scan position</quote> function</entry>
</row>
<row>
<entry>ambuild</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry><quote>build new index</quote> function</entry>
</row>
<row>
<entry>ambulkdelete</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry>bulk-delete function</entry>
</row>
<row>
<entry>amcostestimate</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry>estimate cost of an indexscan</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
An index AM that supports multiple columns (has
<structfield>amcanmulticol</structfield> true) <emphasis>must</>
support indexing nulls in columns after the first, because the planner
will assume the index can be used for queries on just the first
column(s). For example, consider an index on (a,b) and a query
WHERE a = 4. The system will assume the index can be used to scan for
rows with a = 4, which is wrong if the index omits rows where b is null.
However it is okay to omit rows where the first indexed column is null.
(GiST currently does so.)
<structfield>amindexnulls</structfield> should be set true only if the
index AM indexes all rows, including arbitrary combinations of nulls.
</para>
</sect1>
<sect1 id="catalog-pg-amop">
<title>pg_amop</title>
<para>
<structname>pg_amop</structname> stores information about operators
associated with index access method operator classes. There is one
row for each operator that is a member of an operator class.
</para>
<table>
<title>pg_amop Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>amopclaid</entry>
<entry><type>oid</type></entry>
<entry>pg_opclass.oid</entry>
<entry>the index opclass this entry is for</entry>
</row>
<row>
<entry>amopstrategy</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>operator strategy number</entry>
</row>
<row>
<entry>amopreqcheck</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>index hit must be rechecked</entry>
</row>
<row>
<entry>amopopr</entry>
<entry><type>oid</type></entry>
<entry>pg_operator.oid</entry>
<entry>the operator's pg_operator OID</entry>
</row>
</tbody>
</tgroup>
</table>
</sect1>
<sect1 id="catalog-pg-amproc">
<title>pg_amproc</title>
<para>
<structname>pg_amproc</structname> stores information about support
procedures
associated with index access method operator classes. There is one
row for each support procedure belonging to an operator class.
</para>
<table>
<title>pg_amproc Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>amopclaid</entry>
<entry><type>oid</type></entry>
<entry>pg_opclass.oid</entry>
<entry>the index opclass this entry is for</entry>
</row>
<row>
<entry>amprocnum</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>support procedure index</entry>
</row>
<row>
<entry>amproc</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry>OID of the proc</entry>
</row>
</tbody>
</tgroup>
</table>
</sect1>
Use <sect1> rather than <section> to simplify formatting.
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<sect1 id="catalog-pg-attrdef">
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<title>pg_attrdef</title>
<para>
This catalog stores column default values. The main information
about columns is stored in <structname>pg_attribute</structname>
(see below). Only columns that explicitly specify a default value
(when the table is created or the column is added) will have an
entry here.
</para>
<table>
<title>pg_attrdef Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>adrelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>The table this column belongs to</entry>
</row>
<row>
<entry>adnum</entry>
<entry><type>int2</type></entry>
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
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<entry>pg_attribute.attnum</entry>
<entry>The number of the column</entry>
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</row>
<row>
<entry>adbin</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry>An internal representation of the column default value</entry>
</row>
<row>
<entry>adsrc</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry>A human-readable representation of the default value</entry>
</row>
</tbody>
</tgroup>
</table>
Use <sect1> rather than <section> to simplify formatting.
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</sect1>
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<sect1 id="catalog-pg-attribute">
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<title>pg_attribute</title>
<para>
<structname>pg_attribute</structname> stores information about
table columns. There will be exactly one
<structname>pg_attribute</structname> row for every column in every
table in the database. (There will also be attribute entries for
indexes and other objects. See <structname>pg_class</structname>.)
</para>
<para>
The term attribute is equivalent to column and is used for
historical reasons.
</para>
<table>
<title>pg_attribute Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>attrelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>The table this column belongs to</entry>
</row>
<row>
<entry>attname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Column name</entry>
</row>
<row>
<entry>atttypid</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>The data type of this column</entry>
</row>
<row>
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
<entry>attstattarget</entry>
<entry><type>int4</type></entry>
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<entry></entry>
<entry>
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
<structfield>attstattarget</structfield> controls the level of detail
of statistics accumulated for this column by
<command>ANALYZE</command>.
A zero value indicates that no statistics should be collected.
Instead of having a configure-time DEFAULT_ATTSTATTARGET, store -1 in attstattarget to indicate 'use the default'. The default is now a GUC variable default_statistics_target, and so may be changed on the fly. Along the way we gain the ability to have pg_dump dump the per-column statistics target when it's not the default. Patch by Neil Conway, with some kibitzing from Tom Lane.
2002-07-31 19:19:54 +02:00
A negative value says to use the system default statistics target.
The exact meaning of positive values is datatype-dependent.
For scalar datatypes, <structfield>attstattarget</structfield>
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
is both the target number of <quote>most common values</quote>
to collect, and the target number of histogram bins to create.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>attlen</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
This is a copy of
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<structname>pg_type</structname>.<structfield>typlen</structfield>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
of this column's type.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>attnum</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>
The number of the column. Ordinary columns are numbered from 1
up. System columns, such as <structfield>oid</structfield>,
have (arbitrary) negative numbers.
</entry>
</row>
<row>
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
<entry>attndims</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry><type>int4</type></entry>
<entry></entry>
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
<entry>
Clean up wrong, misleading, or obsolete documentation about array types, particularly in the CREATE TYPE reference page. Fix some other errors in the CREATE TYPE page, too.
2001-11-03 22:42:47 +01:00
Number of dimensions, if the column is an array type; otherwise 0.
(Presently, the number of dimensions of an array is not enforced,
so any nonzero value effectively means <quote>it's an array</>.)
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>attcacheoff</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>
Always -1 in storage, but when loaded into a tuple descriptor
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
in memory this may be updated to cache the offset of the attribute
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
within the tuple.
</entry>
</row>
<row>
<entry>atttypmod</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>
<structfield>atttypmod</structfield> records type-specific data
supplied at table creation time (for example, the maximum
length of a <type>varchar</type> column). It is passed to
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
type-specific input functions and length coercion functions.
The value will generally be -1 for types that do not need typmod.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>attbyval</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
A copy of
<structname>pg_type</structname>.<structfield>typbyval</structfield>
of this column's type
</entry>
</row>
<row>
<entry>attstorage</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
Normally a copy of
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<structname>pg_type</structname>.<structfield>typstorage</structfield>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
of this column's type. For TOASTable datatypes, this can be altered
after column creation to control storage policy.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>attisset</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
If true, this attribute is a set. In that case, what is really
stored in the attribute is the OID of a tuple in the
<structname>pg_proc</structname> catalog. The
<structname>pg_proc</structname> tuple contains the query
Replace incorrect uses of 'which' with 'that'. (so-called "wicked which")
2000-12-22 19:57:50 +01:00
string that defines this set - i.e., the query to run to get
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
the set. So the <structfield>atttypid</structfield> (see
above) refers to the type returned by this query, but the
actual length of this attribute is the length (size) of an
<type>oid</type>. --- At least this is the theory. All this
is probably quite broken these days.
</entry>
</row>
<row>
<entry>attalign</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>
A copy of
<structname>pg_type</structname>.<structfield>typalign</structfield>
of this column's type
</entry>
</row>
<row>
<entry>attnotnull</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
This represents a NOT NULL constraint. It is possible to
change this field to enable or disable the constraint.
</entry>
</row>
<row>
<entry>atthasdef</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
This column has a default value, in which case there will be a
corresponding entry in the <structname>pg_attrdef</structname>
catalog that actually defines the value.
</entry>
</row>
ALTER TABLE DROP COLUMN works. Patch by Christopher Kings-Lynne, code review by Tom Lane. Remaining issues: functions that take or return tuple types are likely to break if one drops (or adds!) a column in the table defining the type. Need to think about what to do here. Along the way: some code review for recent COPY changes; mark system columns attnotnull = true where appropriate, per discussion a month ago.
2002-08-02 20:15:10 +02:00
<row>
<entry>attisdropped</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
This column has been dropped and is no longer valid. A dropped
column is still physically present in the table, but is
ignored by the parser and so cannot be accessed via SQL.
</entry>
</row>
Add attisinherited column to pg_attribute; use it to guard against column additions, deletions, and renames that would let a child table get out of sync with its parent. Patch by Alvaro Herrera, with some kibitzing by Tom Lane.
2002-08-30 21:23:20 +02:00
<row>
Replace pg_attribute.attisinherited with attislocal and attinhcount columns, to allow more correct behavior in multiple-inheritance cases. Patch by Alvaro Herrera, review by Tom Lane.
2002-09-22 21:42:52 +02:00
<entry>attislocal</entry>
Add attisinherited column to pg_attribute; use it to guard against column additions, deletions, and renames that would let a child table get out of sync with its parent. Patch by Alvaro Herrera, with some kibitzing by Tom Lane.
2002-08-30 21:23:20 +02:00
<entry><type>bool</type></entry>
<entry></entry>
<entry>
Replace pg_attribute.attisinherited with attislocal and attinhcount columns, to allow more correct behavior in multiple-inheritance cases. Patch by Alvaro Herrera, review by Tom Lane.
2002-09-22 21:42:52 +02:00
This column is defined locally in the relation. Note that a column may
be locally defined and inherited simultaneously.
</entry>
</row>
<row>
<entry>attinhcount</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>
The number of direct ancestors this column has. A column with a
nonzero number of ancestors cannot be dropped nor renamed.
Add attisinherited column to pg_attribute; use it to guard against column additions, deletions, and renames that would let a child table get out of sync with its parent. Patch by Alvaro Herrera, with some kibitzing by Tom Lane.
2002-08-30 21:23:20 +02:00
</entry>
</row>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</tbody>
</tgroup>
</table>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
</sect1>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
Add unique index on pg_cast.oid, and document pg_cast table.
2002-07-22 22:23:19 +02:00
<sect1 id="catalog-pg-cast">
<title>pg_cast</title>
<para>
Extend pg_cast castimplicit column to a three-way value; this allows us to be flexible about assignment casts without introducing ambiguity in operator/function resolution. Introduce a well-defined promotion hierarchy for numeric datatypes (int2->int4->int8->numeric->float4->float8). Change make_const to initially label numeric literals as int4, int8, or numeric (never float8 anymore). Explicitly mark Func and RelabelType nodes to indicate whether they came from a function call, explicit cast, or implicit cast; use this to do reverse-listing more accurately and without so many heuristics. Explicit casts to char, varchar, bit, varbit will truncate or pad without raising an error (the pre-7.2 behavior), while assigning to a column without any explicit cast will still raise an error for wrong-length data like 7.3. This more nearly follows the SQL spec than 7.2 behavior (we should be reporting a 'completion condition' in the explicit-cast cases, but we have no mechanism for that, so just do silent truncation). Fix some problems with enforcement of typmod for array elements; it didn't work at all in 'UPDATE ... SET array[n] = foo', for example. Provide a generalized array_length_coerce() function to replace the specialized per-array-type functions that used to be needed (and were missing for NUMERIC as well as all the datetime types). Add missing conversions int8<->float4, text<->numeric, oid<->int8. initdb forced.
2002-09-18 23:35:25 +02:00
<structname>pg_cast</structname> stores data type conversion paths,
both built-in paths and those defined with <command>CREATE CAST</command>.
Add unique index on pg_cast.oid, and document pg_cast table.
2002-07-22 22:23:19 +02:00
</para>
<table>
<title>pg_cast Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>castsource</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>OID of the source data type</entry>
</row>
<row>
<entry>casttarget</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>OID of the target data type</entry>
</row>
<row>
<entry>castfunc</entry>
<entry><type>oid</type></entry>
<entry>pg_proc.oid</entry>
<entry>
Extend pg_cast castimplicit column to a three-way value; this allows us to be flexible about assignment casts without introducing ambiguity in operator/function resolution. Introduce a well-defined promotion hierarchy for numeric datatypes (int2->int4->int8->numeric->float4->float8). Change make_const to initially label numeric literals as int4, int8, or numeric (never float8 anymore). Explicitly mark Func and RelabelType nodes to indicate whether they came from a function call, explicit cast, or implicit cast; use this to do reverse-listing more accurately and without so many heuristics. Explicit casts to char, varchar, bit, varbit will truncate or pad without raising an error (the pre-7.2 behavior), while assigning to a column without any explicit cast will still raise an error for wrong-length data like 7.3. This more nearly follows the SQL spec than 7.2 behavior (we should be reporting a 'completion condition' in the explicit-cast cases, but we have no mechanism for that, so just do silent truncation). Fix some problems with enforcement of typmod for array elements; it didn't work at all in 'UPDATE ... SET array[n] = foo', for example. Provide a generalized array_length_coerce() function to replace the specialized per-array-type functions that used to be needed (and were missing for NUMERIC as well as all the datetime types). Add missing conversions int8<->float4, text<->numeric, oid<->int8. initdb forced.
2002-09-18 23:35:25 +02:00
The OID of the function to use to perform this cast. Zero is
stored if the data types are binary coercible (that is, no
run-time operation is needed to perform the cast).
Add unique index on pg_cast.oid, and document pg_cast table.
2002-07-22 22:23:19 +02:00
</entry>
</row>
<row>
Extend pg_cast castimplicit column to a three-way value; this allows us to be flexible about assignment casts without introducing ambiguity in operator/function resolution. Introduce a well-defined promotion hierarchy for numeric datatypes (int2->int4->int8->numeric->float4->float8). Change make_const to initially label numeric literals as int4, int8, or numeric (never float8 anymore). Explicitly mark Func and RelabelType nodes to indicate whether they came from a function call, explicit cast, or implicit cast; use this to do reverse-listing more accurately and without so many heuristics. Explicit casts to char, varchar, bit, varbit will truncate or pad without raising an error (the pre-7.2 behavior), while assigning to a column without any explicit cast will still raise an error for wrong-length data like 7.3. This more nearly follows the SQL spec than 7.2 behavior (we should be reporting a 'completion condition' in the explicit-cast cases, but we have no mechanism for that, so just do silent truncation). Fix some problems with enforcement of typmod for array elements; it didn't work at all in 'UPDATE ... SET array[n] = foo', for example. Provide a generalized array_length_coerce() function to replace the specialized per-array-type functions that used to be needed (and were missing for NUMERIC as well as all the datetime types). Add missing conversions int8<->float4, text<->numeric, oid<->int8. initdb forced.
2002-09-18 23:35:25 +02:00
<entry>castcontext</entry>
<entry><type>char</type></entry>
Add unique index on pg_cast.oid, and document pg_cast table.
2002-07-22 22:23:19 +02:00
<entry></entry>
Extend pg_cast castimplicit column to a three-way value; this allows us to be flexible about assignment casts without introducing ambiguity in operator/function resolution. Introduce a well-defined promotion hierarchy for numeric datatypes (int2->int4->int8->numeric->float4->float8). Change make_const to initially label numeric literals as int4, int8, or numeric (never float8 anymore). Explicitly mark Func and RelabelType nodes to indicate whether they came from a function call, explicit cast, or implicit cast; use this to do reverse-listing more accurately and without so many heuristics. Explicit casts to char, varchar, bit, varbit will truncate or pad without raising an error (the pre-7.2 behavior), while assigning to a column without any explicit cast will still raise an error for wrong-length data like 7.3. This more nearly follows the SQL spec than 7.2 behavior (we should be reporting a 'completion condition' in the explicit-cast cases, but we have no mechanism for that, so just do silent truncation). Fix some problems with enforcement of typmod for array elements; it didn't work at all in 'UPDATE ... SET array[n] = foo', for example. Provide a generalized array_length_coerce() function to replace the specialized per-array-type functions that used to be needed (and were missing for NUMERIC as well as all the datetime types). Add missing conversions int8<->float4, text<->numeric, oid<->int8. initdb forced.
2002-09-18 23:35:25 +02:00
<entry>
Indicates what contexts the cast may be invoked in.
<literal>e</> means only as an explicit cast (using
<literal>CAST</>, <literal>::</>, or function-call syntax).
<literal>a</> means implicitly in assignment
to a target column, as well as explicitly.
<literal>i</> means implicitly in expressions, as well as the
other cases.
</entry>
Add unique index on pg_cast.oid, and document pg_cast table.
2002-07-22 22:23:19 +02:00
</row>
</tbody>
</tgroup>
</table>
</sect1>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
<sect1 id="catalog-pg-class">
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<title>pg_class</title>
<para>
Update info about relkind and pg_type entries for composite-types patch.
2002-08-28 17:02:55 +02:00
<structname>pg_class</structname> catalogs tables and most
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
everything else that has columns or is otherwise similar to a
Make OIDs optional, per discussions in pghackers. WITH OIDS is still the default, but OIDS are removed from many system catalogs that don't need them. Some interesting side effects: TOAST pointers are 20 bytes not 32 now; pg_description has a three-column key instead of one. Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey has some usefulness; pg_dump dumps comments on indexes, rules, and triggers in a valid order. initdb forced.
2001-08-10 20:57:42 +02:00
table. This includes indexes (but see also
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<structname>pg_index</structname>), sequences, views, and some
Update info about relkind and pg_type entries for composite-types patch.
2002-08-28 17:02:55 +02:00
kinds of special relation; see <structfield>relkind</>.
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
Below, when we mean all of these
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
kinds of objects we speak of <quote>relations</quote>. Not all
fields are meaningful for all relation types.
</para>
<table>
<title>pg_class Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>relname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Name of the table, index, view, etc.</entry>
</row>
pg_class has a relnamespace column. You can create and access tables in schemas other than the system namespace; however, there's no search path yet, and not all operations work yet on tables outside the system namespace.
2002-03-26 20:17:02 +01:00
<row>
<entry>relnamespace</entry>
<entry><type>oid</type></entry>
<entry>pg_namespace.oid</entry>
<entry>
The OID of the namespace that contains this relation
</entry>
</row>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<row>
<entry>reltype</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>
Make OIDs optional, per discussions in pghackers. WITH OIDS is still the default, but OIDS are removed from many system catalogs that don't need them. Some interesting side effects: TOAST pointers are 20 bytes not 32 now; pg_description has a three-column key instead of one. Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey has some usefulness; pg_dump dumps comments on indexes, rules, and triggers in a valid order. initdb forced.
2001-08-10 20:57:42 +02:00
The OID of the data type that corresponds to this table, if any
(zero for indexes, which have no pg_type entry)
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>relowner</entry>
<entry><type>int4</type></entry>
<entry>pg_shadow.usesysid</entry>
<entry>Owner of the relation</entry>
</row>
<row>
<entry>relam</entry>
<entry><type>oid</type></entry>
<entry>pg_am.oid</entry>
Spell checking and markup additions
2002-03-22 20:20:45 +01:00
<entry>If this is an index, the access method used (B-tree, hash, etc.)</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>relfilenode</entry>
<entry><type>oid</type></entry>
<entry></entry>
Update info about relkind and pg_type entries for composite-types patch.
2002-08-28 17:02:55 +02:00
<entry>Name of the on-disk file of this relation; 0 if none</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>relpages</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>
Size of the on-disk representation of this table in pages (size
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
<symbol>BLCKSZ</symbol>).
This is only an estimate used by the planner.
It is updated by <command>VACUUM</command>,
<command>ANALYZE</command>, and <command>CREATE INDEX</command>.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>reltuples</entry>
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
<entry><type>float4</type></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry></entry>
<entry>
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
Number of tuples in the table.
This is only an estimate used by the planner.
It is updated by <command>VACUUM</command>,
<command>ANALYZE</command>, and <command>CREATE INDEX</command>.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>reltoastrelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>
Spell checking and markup additions
2002-03-22 20:20:45 +01:00
OID of the TOAST table associated with this table, 0 if none.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
The TOAST table stores large attributes <quote>out of
line</quote> in a secondary table.
</entry>
</row>
<row>
<entry>reltoastidxid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
Make OIDs optional, per discussions in pghackers. WITH OIDS is still the default, but OIDS are removed from many system catalogs that don't need them. Some interesting side effects: TOAST pointers are 20 bytes not 32 now; pg_description has a three-column key instead of one. Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey has some usefulness; pg_dump dumps comments on indexes, rules, and triggers in a valid order. initdb forced.
2001-08-10 20:57:42 +02:00
<entry>
For a TOAST table, the OID of its index. 0 if not a TOAST table.
</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>relhasindex</entry>
<entry><type>bool</type></entry>
<entry></entry>
Improvement to CREATE TRIGGER and catalog documentation. Neil Conway
2002-12-17 18:41:30 +01:00
<entry>
True if this is a table and it has (or recently had) any
indexes. This is set by <command>CREATE INDEX</command>, but
not cleared immediately by <command>DROP INDEX</command>.
<command>VACUUM</command> clears relhasindex if it finds the
table has no indexes.
Make OIDs optional, per discussions in pghackers. WITH OIDS is still the default, but OIDS are removed from many system catalogs that don't need them. Some interesting side effects: TOAST pointers are 20 bytes not 32 now; pg_description has a three-column key instead of one. Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey has some usefulness; pg_dump dumps comments on indexes, rules, and triggers in a valid order. initdb forced.
2001-08-10 20:57:42 +02:00
</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>relisshared</entry>
<entry><type>bool</type></entry>
<entry></entry>
Clean up various to-do items associated with system indexes: pg_database now has unique indexes on oid and on datname. pg_shadow now has unique indexes on usename and on usesysid. pg_am now has unique index on oid. pg_opclass now has unique index on oid. pg_amproc now has unique index on amid+amopclaid+amprocnum. Remove pg_rewrite's unnecessary index on oid, delete unused RULEOID syscache. Remove index on pg_listener and associated syscache for performance reasons (caching rows that are certain to change before you need 'em again is rather pointless). Change pg_attrdef's nonunique index on adrelid into a unique index on adrelid+adnum. Fix various incorrect settings of pg_class.relisshared, make that the primary reference point for whether a relation is shared or not. IsSharedSystemRelationName() is now only consulted to initialize relisshared during initial creation of tables and indexes. In theory we might now support shared user relations, though it's not clear how one would get entries for them into pg_class &etc of multiple databases. Fix recently reported bug that pg_attribute rows created for an index all have the same OID. (Proof that non-unique OID doesn't matter unless it's actually used to do lookups ;-)) There's no need to treat pg_trigger, pg_attrdef, pg_relcheck as bootstrap relations. Convert them into plain system catalogs without hardwired entries in pg_class and friends. Unify global.bki and template1.bki into a single init script postgres.bki, since the alleged distinction between them was misleading and pointless. Not to mention that it didn't work for setting up indexes on shared system relations. Rationalize locking of pg_shadow, pg_group, pg_attrdef (no need to use AccessExclusiveLock where ExclusiveLock or even RowExclusiveLock will do). Also, hold locks until transaction commit where necessary.
2001-06-12 07:55:50 +02:00
<entry>True if this table is shared across all databases in the
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
cluster. Only certain system catalogs (such as
<structname>pg_database</structname>) are shared.</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>relkind</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>
'r' = ordinary table, 'i' = index, 'S' = sequence, 'v' = view,
Update info about relkind and pg_type entries for composite-types patch.
2002-08-28 17:02:55 +02:00
'c' = composite type, 's' = special, 't' = TOAST table
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>relnatts</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>
Make OIDs optional, per discussions in pghackers. WITH OIDS is still the default, but OIDS are removed from many system catalogs that don't need them. Some interesting side effects: TOAST pointers are 20 bytes not 32 now; pg_description has a three-column key instead of one. Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey has some usefulness; pg_dump dumps comments on indexes, rules, and triggers in a valid order. initdb forced.
2001-08-10 20:57:42 +02:00
Number of user columns in the relation (system columns not counted).
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
There must be this many corresponding entries in
<structname>pg_attribute</structname>. See also
<structname>pg_attribute</structname>.<structfield>attnum</structfield>.
</entry>
</row>
<row>
<entry>relchecks</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>
Number of check constraints on the table; see
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
2002-07-12 20:43:19 +02:00
<structname>pg_constraint</structname> catalog
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>reltriggers</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>
Number of triggers on the table; see
<structname>pg_trigger</structname> catalog
</entry>
</row>
<row>
<entry>relukeys</entry>
<entry><type>int2</type></entry>
<entry></entry>
Make OIDs optional, per discussions in pghackers. WITH OIDS is still the default, but OIDS are removed from many system catalogs that don't need them. Some interesting side effects: TOAST pointers are 20 bytes not 32 now; pg_description has a three-column key instead of one. Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey has some usefulness; pg_dump dumps comments on indexes, rules, and triggers in a valid order. initdb forced.
2001-08-10 20:57:42 +02:00
<entry>unused (<emphasis>Not</emphasis> the number of unique keys)</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>relfkeys</entry>
<entry><type>int2</type></entry>
<entry></entry>
Make OIDs optional, per discussions in pghackers. WITH OIDS is still the default, but OIDS are removed from many system catalogs that don't need them. Some interesting side effects: TOAST pointers are 20 bytes not 32 now; pg_description has a three-column key instead of one. Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey has some usefulness; pg_dump dumps comments on indexes, rules, and triggers in a valid order. initdb forced.
2001-08-10 20:57:42 +02:00
<entry>unused (<emphasis>Not</emphasis> the number of foreign keys on the table)</entry>
</row>
<row>
<entry>relrefs</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>unused</entry>
</row>
<row>
<entry>relhasoids</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
True if we generate an OID for each row of the relation.
</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>relhaspkey</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
Make OIDs optional, per discussions in pghackers. WITH OIDS is still the default, but OIDS are removed from many system catalogs that don't need them. Some interesting side effects: TOAST pointers are 20 bytes not 32 now; pg_description has a three-column key instead of one. Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey has some usefulness; pg_dump dumps comments on indexes, rules, and triggers in a valid order. initdb forced.
2001-08-10 20:57:42 +02:00
True if the table has (or once had) a primary key.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>relhasrules</entry>
<entry><type>bool</type></entry>
<entry></entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<entry>Table has rules; see
<structname>pg_rewrite</structname> catalog
</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>relhassubclass</entry>
<entry><type>bool</type></entry>
<entry></entry>
Make OIDs optional, per discussions in pghackers. WITH OIDS is still the default, but OIDS are removed from many system catalogs that don't need them. Some interesting side effects: TOAST pointers are 20 bytes not 32 now; pg_description has a three-column key instead of one. Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey has some usefulness; pg_dump dumps comments on indexes, rules, and triggers in a valid order. initdb forced.
2001-08-10 20:57:42 +02:00
<entry>At least one table inherits from this one</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>relacl</entry>
<entry><type>aclitem[]</type></entry>
<entry></entry>
<entry>
Access permissions. See the descriptions of
<command>GRANT</command> and <command>REVOKE</command> for
details.
</entry>
</row>
</tbody>
</tgroup>
</table>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
</sect1>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
2002-07-12 20:43:19 +02:00
<sect1 id="catalog-pg-constraint">
<title>pg_constraint</title>
<para>
This system catalog stores CHECK, PRIMARY KEY, UNIQUE, and FOREIGN KEY
constraints on tables. (Column
constraints are not treated specially. Every column constraint is
equivalent to some table constraint.) See under <command>CREATE
TABLE</command> for more information.
</para>
<note>
<para>
NOT NULL constraints are represented in the <structname>pg_attribute</>
catalog.
</para>
</note>
<para>
CHECK constraints on domains are stored here, too. Global ASSERTIONS
(a currently-unsupported SQL feature) may someday appear here as well.
</para>
<table>
<title>pg_constraint Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>conname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Constraint name (not necessarily unique!)</entry>
</row>
<row>
<entry>connamespace</entry>
<entry><type>oid</type></entry>
<entry>pg_namespace.oid</entry>
<entry>
The OID of the namespace that contains this constraint
</entry>
</row>
<row>
<entry>contype</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>
'c' = check constraint,
Replace pg_attribute.attisinherited with attislocal and attinhcount columns, to allow more correct behavior in multiple-inheritance cases. Patch by Alvaro Herrera, review by Tom Lane.
2002-09-22 21:42:52 +02:00
'f' = foreign key constraint,
'p' = primary key constraint,
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
2002-07-12 20:43:19 +02:00
'u' = unique constraint
</entry>
</row>
<row>
<entry>condeferrable</entry>
<entry><type>boolean</type></entry>
<entry></entry>
<entry>Is the constraint deferrable?</entry>
</row>
<row>
<entry>condeferred</entry>
<entry><type>boolean</type></entry>
<entry></entry>
<entry>Is the constraint deferred by default?</entry>
</row>
<row>
<entry>conrelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>The table this constraint is on; 0 if not a table constraint</entry>
</row>
<row>
<entry>contypid</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>The domain this constraint is on; 0 if not a domain constraint</entry>
</row>
<row>
<entry>confrelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>If a foreign key, the referenced table; else 0</entry>
</row>
<row>
<entry>confupdtype</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>Foreign key update action code</entry>
</row>
<row>
<entry>confdeltype</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>Foreign key deletion action code</entry>
</row>
<row>
<entry>confmatchtype</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>Foreign key match type</entry>
</row>
<row>
<entry>conkey</entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<entry><type>int2[]</type></entry>
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
2002-07-12 20:43:19 +02:00
<entry>pg_attribute.attnum</entry>
<entry>If a table constraint, list of columns which the constraint constrains</entry>
</row>
<row>
<entry>confkey</entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<entry><type>int2[]</type></entry>
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
2002-07-12 20:43:19 +02:00
<entry>pg_attribute.attnum</entry>
<entry>If a foreign key, list of the referenced columns</entry>
</row>
<row>
<entry>conbin</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry>If a check constraint, an internal representation of the expression</entry>
</row>
<row>
<entry>consrc</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry>If a check constraint, a human-readable representation of the expression</entry>
</row>
</tbody>
</tgroup>
</table>
<note>
<para>
<structname>pg_class</structname>.<structfield>relchecks</structfield>
needs to agree with the number of check-constraint entries found in this
table for the given relation.
</para>
</note>
</sect1>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
Add pg_conversion system catalog. Update description for multibyte support.
2002-07-24 07:51:56 +02:00
<sect1 id="catalog-pg-conversion">
<title>pg_conversion</title>
<para>
This system catalog stores encoding conversion information. See
<command>CREATE CONVERSION</command> for more information.
</para>
<table>
<title>pg_conversion Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>conname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Conversion name (unique within a namespace)</entry>
</row>
<row>
<entry>connamespace</entry>
<entry><type>oid</type></entry>
<entry>pg_namespace.oid</entry>
<entry>
The OID of the namespace that contains this conversion
</entry>
</row>
<row>
<entry>conowner</entry>
<entry><type>int4</type></entry>
<entry>pg_shadow.usesysid</entry>
<entry>Owner (creator) of the namespace</entry>
</row>
<row>
<entry>conforencoding</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>Source(for) encoding ID</entry>
</row>
<row>
<entry>contoencoding</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>Destination(to) encoding ID</entry>
</row>
<row>
<entry>conproc</entry>
<entry><type>regproc</type></entry>
<entry>pg_proc.oid</entry>
<entry>Conversion procedure</entry>
</row>
<row>
<entry>condefault</entry>
<entry><type>boolean</type></entry>
<entry></entry>
<entry>true if this is the default conversion</entry>
</row>
</tbody>
</tgroup>
</table>
</sect1>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
<sect1 id="catalog-pg-database">
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<title>pg_database</title>
<para>
The <structname>pg_database</structname> catalog stores information
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
about the available databases. Databases are created with the
<command>CREATE DATABASE</command> command. Consult the
This patch includes a lot of minor cleanups to the SGML documentation, including: - replacing all the appropriate usages of <citetitle>PostgreSQL ...</citetitle> with &cite-user;, &cite-admin;, and so on - fix an omission in the EXECUTE documentation - add some more text to the EXPLAIN documentation - improve the PL/PgSQL RETURN NEXT documentation (more work to do here) - minor markup fixes Neil Conway
2003-01-19 01:13:31 +01:00
&cite-admin; for details about the meaning of some of the
parameters.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</para>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<para>
Unlike most system catalogs, <structname>pg_database</structname>
is shared across all databases of a cluster: there is only one
copy of <structname>pg_database</structname> per cluster, not
one per database.
</para>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<table>
<title>pg_database Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>datname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Database name</entry>
</row>
<row>
<entry>datdba</entry>
<entry><type>int4</type></entry>
<entry>pg_shadow.usesysid</entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<entry>Owner of the database, usually the user who created it</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>encoding</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>Character/multibyte encoding for this database</entry>
</row>
<row>
<entry>datistemplate</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
If true then this database can be used in the
<quote>TEMPLATE</quote> clause of <command>CREATE
Restructure AclItem representation so that we can have more than eight different privilege bits (might as well make use of the space we were wasting on padding). EXECUTE and USAGE bits for procedures, languages now are separate privileges instead of being overlaid on SELECT. Add privileges for namespaces and databases. The GRANT and REVOKE commands work for these object types, but we don't actually enforce the privileges yet...
2002-04-21 02:26:44 +02:00
DATABASE</command> to create a new database as a clone of
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
this one.
</entry>
</row>
<row>
<entry>datallowconn</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
If false then no one can connect to this database. This is
used to protect the template0 database from being altered.
</entry>
</row>
<row>
<entry>datlastsysoid</entry>
<entry><type>oid</type></entry>
<entry></entry>
<entry>
Transaction IDs wrap around, per my proposal of 13-Aug-01. More documentation to come, but the code is all here. initdb forced.
2001-08-26 18:56:03 +02:00
Last system OID in the database; useful
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
particularly to <application>pg_dump</application>
</entry>
</row>
Transaction IDs wrap around, per my proposal of 13-Aug-01. More documentation to come, but the code is all here. initdb forced.
2001-08-26 18:56:03 +02:00
<row>
<entry>datvacuumxid</entry>
<entry><type>xid</type></entry>
<entry></entry>
<entry>
All tuples inserted or deleted by transaction IDs before this one
have been marked as known committed or known aborted in this database.
This is used to determine when commit-log space can be recycled.
</entry>
</row>
<row>
<entry>datfrozenxid</entry>
<entry><type>xid</type></entry>
<entry></entry>
<entry>
All tuples inserted by transaction IDs before this one have been
relabeled with a permanent (<quote>frozen</>) transaction ID in this
database. This is useful to check whether a database must be vacuumed
soon to avoid transaction ID wraparound problems.
</entry>
</row>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<row>
<entry>datpath</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry>
If the database is stored at an alternative location then this
records the location. It's either an environment variable name
or an absolute path, depending how it was entered.
</entry>
</row>
User and database-specific session defaults for run-time configuration variables. New commands ALTER DATABASE ... SET and ALTER USER ... SET.
2002-03-01 23:45:19 +01:00
<row>
<entry>datconfig</entry>
<entry><type>text[]</type></entry>
<entry></entry>
<entry>Session defaults for run-time configuration variables</entry>
</row>
Restructure AclItem representation so that we can have more than eight different privilege bits (might as well make use of the space we were wasting on padding). EXECUTE and USAGE bits for procedures, languages now are separate privileges instead of being overlaid on SELECT. Add privileges for namespaces and databases. The GRANT and REVOKE commands work for these object types, but we don't actually enforce the privileges yet...
2002-04-21 02:26:44 +02:00
<row>
<entry>datacl</entry>
<entry><type>aclitem[]</type></entry>
<entry></entry>
<entry>Access permissions</entry>
</row>
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</tbody>
</tgroup>
</table>
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</sect1>
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Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
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<sect1 id="catalog-pg-depend">
<title>pg_depend</title>
<para>
The <structname>pg_depend</structname> table records the dependency
relationships between database objects. This information allows
<command>DROP</> commands to find which other objects must be dropped
by <command>DROP CASCADE</>, or prevent dropping in the <command>DROP
RESTRICT</> case.
</para>
<table>
<title>pg_depend Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>classid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>The oid of the system catalog the dependent object is in</entry>
</row>
<row>
<entry>objid</entry>
<entry><type>oid</type></entry>
<entry>any oid attribute</entry>
<entry>The oid of the specific dependent object</entry>
</row>
<row>
<entry>objsubid</entry>
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<entry><type>int4</type></entry>
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
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<entry></entry>
<entry>For a table attribute, this is the attribute's
column number (the objid and classid refer to the table itself).
For all other object types, this field is presently zero.
</entry>
</row>
<row>
<entry>refclassid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>The oid of the system catalog the referenced object is in</entry>
</row>
<row>
<entry>refobjid</entry>
<entry><type>oid</type></entry>
<entry>any oid attribute</entry>
<entry>The oid of the specific referenced object</entry>
</row>
<row>
<entry>refobjsubid</entry>
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<entry><type>int4</type></entry>
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
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<entry></entry>
<entry>For a table attribute, this is the attribute's
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column number (the refobjid and refclassid refer to the table itself).
Second phase of committing Rod Taylor's pg_depend/pg_constraint patch. pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints all have real live entries in pg_constraint. pg_depend exists, and RESTRICT/CASCADE options work on most kinds of DROP; however, pg_depend is not yet very well populated with dependencies. (Most of the ones that are present at this point just replace formerly hardwired associations, such as the implicit drop of a relation's pg_type entry when the relation is dropped.) Need to add more logic to create dependency entries, improve pg_dump to dump constraints in place of indexes and triggers, and add some regression tests.
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For all other object types, this field is presently zero.
</entry>
</row>
<row>
<entry>deptype</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>
A code defining the specific semantics of this dependency relationship.
</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
In all cases, a <structname>pg_depend</structname> entry indicates that the
referenced object may not be dropped without also dropping the dependent
object. However, there are several subflavors identified by
<structfield>deptype</>:
<itemizedlist>
<listitem>
<para>
DEPENDENCY_NORMAL ('n'): normal relationship between separately-created
objects. The dependent object may be dropped without affecting the
referenced object. The referenced object may only be dropped by
specifying CASCADE, in which case the dependent object is dropped too.
Example: a table column has a normal dependency on its datatype.
</para>
</listitem>
<listitem>
<para>
DEPENDENCY_AUTO ('a'): the dependent object can be dropped separately
from the referenced object, and should be automatically dropped
(regardless of RESTRICT or CASCADE mode) if the referenced object
is dropped.
Example: a named constraint on a table is made auto-dependent on
the table, so that it will go away if the table is dropped.
</para>
</listitem>
<listitem>
<para>
DEPENDENCY_INTERNAL ('i'): the dependent object was created as part
of creation of the referenced object, and is really just a part of
its internal implementation. A DROP of the dependent object will be
disallowed outright (we'll tell the user to issue a DROP against the
referenced object, instead). A DROP of the referenced object will be
propagated through to drop the dependent object whether CASCADE is
specified or not.
Example: a trigger that's created to enforce a foreign-key constraint
is made internally dependent on the constraint's pg_constraint entry.
</para>
</listitem>
<listitem>
<para>
DEPENDENCY_PIN ('p'): there is no dependent object; this type of entry
is a signal that the system itself depends on the referenced object,
and so that object must never be deleted. Entries of this type are
created only during initdb. The fields for the dependent object
contain zeroes.
</para>
</listitem>
</itemizedlist>
Other dependency flavors may be needed in future.
</para>
</sect1>
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<sect1 id="catalog-pg-description">
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<title>pg_description</title>
<para>
The pg_description table can store an optional description or
comment for each database object. Descriptions can be manipulated
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with the <command>COMMENT</command> command and viewed with
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<application>psql</application>'s <literal>\d</literal> commands.
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Descriptions of many built-in system objects are provided in the initial
contents of pg_description.
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</para>
<table>
<title>pg_description Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>objoid</entry>
<entry><type>oid</type></entry>
<entry>any oid attribute</entry>
<entry>The oid of the object this description pertains to</entry>
</row>
Make OIDs optional, per discussions in pghackers. WITH OIDS is still the default, but OIDS are removed from many system catalogs that don't need them. Some interesting side effects: TOAST pointers are 20 bytes not 32 now; pg_description has a three-column key instead of one. Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey has some usefulness; pg_dump dumps comments on indexes, rules, and triggers in a valid order. initdb forced.
2001-08-10 20:57:42 +02:00
<row>
<entry>classoid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>The oid of the system catalog this object appears in</entry>
</row>
<row>
<entry>objsubid</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>For a comment on a table attribute, this is the attribute's
column number (the objoid and classoid refer to the table itself).
For all other object types, this field is presently zero.
</entry>
</row>
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<row>
<entry>description</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry>Arbitrary text that serves as the description of this object.</entry>
</row>
</tbody>
</tgroup>
</table>
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</sect1>
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<sect1 id="catalog-pg-group">
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<title>pg_group</title>
<para>
This catalog defines groups and stores what users belong to what
groups. Groups are created with the <command>CREATE
This patch includes a lot of minor cleanups to the SGML documentation, including: - replacing all the appropriate usages of <citetitle>PostgreSQL ...</citetitle> with &cite-user;, &cite-admin;, and so on - fix an omission in the EXECUTE documentation - add some more text to the EXPLAIN documentation - improve the PL/PgSQL RETURN NEXT documentation (more work to do here) - minor markup fixes Neil Conway
2003-01-19 01:13:31 +01:00
GROUP</command> command. Consult the &cite-admin; for information
about user permission management.
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</para>
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<para>
Because user and group identities are cluster-wide,
<structname>pg_group</structname>
is shared across all databases of a cluster: there is only one
copy of <structname>pg_group</structname> per cluster, not
one per database.
</para>
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<table>
<title>pg_group Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>groname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Name of the group</entry>
</row>
<row>
<entry>grosysid</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>An arbitrary number to identify this group</entry>
</row>
<row>
<entry>grolist</entry>
<entry><type>int4[]</type></entry>
<entry>pg_shadow.usesysid</entry>
<entry>An array containing the ids of the users in this group</entry>
</row>
</tbody>
</tgroup>
</table>
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</sect1>
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<sect1 id="catalog-pg-index">
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<title>pg_index</title>
<para>
<structname>pg_index</structname> contains part of the information
about indexes. The rest is mostly in
<structname>pg_class</structname>.
</para>
<table>
<title>pg_index Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>indexrelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
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<entry>The OID of the pg_class entry for this index</entry>
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</row>
<row>
<entry>indrelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
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<entry>The OID of the pg_class entry for the table this index is for</entry>
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</row>
<row>
<entry>indproc</entry>
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2001-10-16 00:47:47 +02:00
<entry><type>regproc</type></entry>
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<entry>pg_proc.oid</entry>
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<entry>The function's OID if this is a functional index,
else zero</entry>
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</row>
<row>
<entry>indkey</entry>
<entry><type>int2vector</type></entry>
<entry>pg_attribute.attnum</entry>
<entry>
Clean up wrong, misleading, or obsolete documentation about array types, particularly in the CREATE TYPE reference page. Fix some other errors in the CREATE TYPE page, too.
2001-11-03 22:42:47 +01:00
This is a vector (array) of up to
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<symbol>INDEX_MAX_KEYS</symbol> values that indicate which
table columns this index pertains to. For example a value of
<literal>1 3</literal> would mean that the first and the third
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column make up the index key. For a functional index, these
columns are the inputs to the function, and the function's return
value is the index key.
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</entry>
</row>
<row>
<entry>indclass</entry>
<entry><type>oidvector</type></entry>
<entry>pg_opclass.oid</entry>
<entry>
For each column in the index key this contains a reference to
the <quote>operator class</quote> to use. See
<structname>pg_opclass</structname> for details.
</entry>
</row>
<row>
<entry>indisclustered</entry>
<entry><type>bool</type></entry>
<entry></entry>
Code review and documentation updates for indisclustered patch.
2002-09-03 03:04:41 +02:00
<entry>If true, the table was last clustered on this index.</entry>
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</row>
<row>
<entry>indisunique</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>If true, this is a unique index.</entry>
</row>
<row>
<entry>indisprimary</entry>
<entry><type>bool</type></entry>
<entry></entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
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<entry>If true, this index represents the primary key of the table.
(indisunique should always be true when this is true.)</entry>
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</row>
<row>
<entry>indreference</entry>
<entry><type>oid</type></entry>
<entry></entry>
<entry>unused</entry>
</row>
<row>
<entry>indpred</entry>
<entry><type>text</type></entry>
<entry></entry>
Restructure index AM interface for index building and index tuple deletion, per previous discussion on pghackers. Most of the duplicate code in different AMs' ambuild routines has been moved out to a common routine in index.c; this means that all index types now do the right things about inserting recently-dead tuples, etc. (I also removed support for EXTEND INDEX in the ambuild routines, since that's about to go away anyway, and it cluttered the code a lot.) The retail indextuple deletion routines have been replaced by a "bulk delete" routine in which the indexscan is inside the access method. I haven't pushed this change as far as it should go yet, but it should allow considerable simplification of the internal bookkeeping for deletions. Also, add flag columns to pg_am to eliminate various hardcoded tests on AM OIDs, and remove unused pg_am columns. Fix rtree and gist index types to not attempt to store NULLs; before this, gist usually crashed, while rtree managed not to crash but computed wacko bounding boxes for NULL entries (which might have had something to do with the performance problems we've heard about occasionally). Add AtEOXact routines to hash, rtree, and gist, all of which have static state that needs to be reset after an error. We discovered this need long ago for btree, but missed the other guys. Oh, one more thing: concurrent VACUUM is now the default.
2001-07-16 00:48:19 +02:00
<entry>Expression tree (in the form of a nodeToString representation)
Update some obsolete comments and column descriptions.
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for partial index predicate. Empty string if not a partial
index.</entry>
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</row>
</tbody>
</tgroup>
</table>
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</sect1>
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<sect1 id="catalog-pg-inherits">
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<title>pg_inherits</title>
<para>
This catalog records information about table inheritance hierarchies.
</para>
<table>
<title>pg_inherits Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>inhrelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>
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The OID of the child table.
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</entry>
</row>
<row>
<entry>inhparent</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
The OID of the parent table.
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</entry>
</row>
<row>
<entry>inhseqno</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>
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If there is more than one parent for a child table (multiple
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inheritance), this number tells the order in which the
inherited columns are to be arranged. The count starts at 1.
</entry>
</row>
</tbody>
</tgroup>
</table>
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</sect1>
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<sect1 id="catalog-pg-language">
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<title>pg_language</title>
<para>
<structname>pg_language</structname> registers call interfaces or
languages in which you can write functions or stored procedures.
See under <command>CREATE LANGUAGE</command> and in the
This patch includes a lot of minor cleanups to the SGML documentation, including: - replacing all the appropriate usages of <citetitle>PostgreSQL ...</citetitle> with &cite-user;, &cite-admin;, and so on - fix an omission in the EXECUTE documentation - add some more text to the EXPLAIN documentation - improve the PL/PgSQL RETURN NEXT documentation (more work to do here) - minor markup fixes Neil Conway
2003-01-19 01:13:31 +01:00
&cite-programmer; for more information about language handlers.
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</para>
<table>
<title>pg_language Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>lanname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Name of the language (to be specified when creating a function)</entry>
</row>
<row>
<entry>lanispl</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
Improvement to CREATE TRIGGER and catalog documentation. Neil Conway
2002-12-17 18:41:30 +01:00
This is false for internal languages (such as
<acronym>SQL</acronym>) and true for user-defined languages.
Currently, <application>pg_dump</application> still uses this
to determine which languages need to be dumped, but this may be
replaced by a different mechanism sometime.
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</entry>
</row>
<row>
<entry>lanpltrusted</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
This is a trusted language. See under <command>CREATE
LANGUAGE</command> what this means. If this is an internal
language (<structfield>lanispl</structfield> is false) then
this field is meaningless.
</entry>
</row>
<row>
<entry>lanplcallfoid</entry>
<entry><type>oid</type></entry>
<entry>pg_proc.oid</entry>
<entry>
For non-internal languages this references the language
handler, which is a special function that is responsible for
executing all functions that are written in the particular
language.
</entry>
</row>
This patch updates the CREATE LANGUAGE & pg_language docs for the 7.3 table structure. Dave Page
2002-06-20 17:44:06 +02:00
<row>
<entry>lanvalidator</entry>
<entry><type>oid</type></entry>
<entry>pg_proc.oid</entry>
<entry>
This references a language validator function that is responsible
for checking the syntax and validity of new functions when they
are created. See under <command>CREATE LANGUAGE</command> for
further information about validators.
</entry>
</row>
Privileges on functions and procedural languages
2002-02-19 00:11:58 +01:00
<row>
<entry>lanacl</entry>
<entry><type>aclitem[]</type></entry>
<entry></entry>
<entry>Access permissions</entry>
</row>
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</tbody>
</tgroup>
</table>
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</sect1>
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<sect1 id="catalog-pg-largeobject">
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
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<title>pg_largeobject</title>
<para>
<structname>pg_largeobject</structname> holds the data making up
<quote>large objects</quote>. A large object is identified by an
OID assigned when it is created. Each large object is broken into
segments or <quote>pages</> small enough to be conveniently stored as rows
in <structname>pg_largeobject</structname>.
The amount of data per page is defined to be LOBLKSIZE (which is currently
BLCKSZ/4, or typically 2Kbytes).
</para>
<table>
<title>pg_largeobject Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>loid</entry>
<entry><type>oid</type></entry>
<entry></entry>
<entry>Identifier of the large object that includes this page</entry>
</row>
<row>
<entry>pageno</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>Page number of this page within its large object
(counting from zero)</entry>
</row>
<row>
<entry>data</entry>
<entry><type>bytea</type></entry>
<entry></entry>
<entry>
Actual data stored in the large object.
This will never be more than LOBLKSIZE bytes, and may be less.
</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
Each row of <structname>pg_largeobject</structname> holds data
for one page of a large object, beginning at
byte offset (pageno * LOBLKSIZE) within the object. The implementation
allows sparse storage: pages may be missing, and may be shorter than
LOBLKSIZE bytes even if they are not the last page of the object.
Missing regions within a large object read as zeroes.
</para>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
</sect1>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
<sect1 id="catalog-pg-listener">
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<title>pg_listener</title>
<para>
<structname>pg_listener</structname> supports the <command>LISTEN</>
and <command>NOTIFY</> commands. A listener creates an entry in
<structname>pg_listener</structname> for each notification name
it is listening for. A notifier scans <structname>pg_listener</structname>
and updates each matching entry to show that a notification has occurred.
The notifier also sends a signal (using the PID recorded in the table)
to awaken the listener from sleep.
</para>
<table>
<title>pg_listener Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>relname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Notify condition name. (The name need not match any actual
relation in the database; the term <quote>relname</> is historical.)
</entry>
</row>
<row>
<entry>listenerpid</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>PID of the backend process that created this entry.</entry>
</row>
<row>
<entry>notification</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>
Zero if no event is pending for this listener. If an event is
pending, the PID of the backend that sent the notification.
</entry>
</row>
</tbody>
</tgroup>
</table>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
</sect1>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
Create the pg_namespace system catalog. Doesn't do much yet, but it's there and CREATE SCHEMA will make entries in it...
2002-03-22 22:34:44 +01:00
<sect1 id="catalog-pg-namespace">
<title>pg_namespace</title>
<para>
A namespace is the structure underlying SQL92 schemas: each namespace
can have a separate collection of relations, types, etc without name
conflicts.
</para>
<table>
<title>pg_namespace Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>nspname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Name of the namespace</entry>
</row>
<row>
<entry>nspowner</entry>
<entry><type>int4</type></entry>
<entry>pg_shadow.usesysid</entry>
<entry>Owner (creator) of the namespace</entry>
</row>
<row>
<entry>nspacl</entry>
<entry><type>aclitem[]</type></entry>
<entry></entry>
<entry>Access permissions</entry>
</row>
</tbody>
</tgroup>
</table>
</sect1>
Rewrite xindex.sgml for CREATE OPERATOR CLASS. catalogs.sgml finally contains descriptions of every single system table. Update 'complex' tutorial example too.
2002-07-30 07:24:56 +02:00
<sect1 id="catalog-pg-opclass">
<title>pg_opclass</title>
<para>
<structname>pg_opclass</structname> defines
index access method operator classes. Each operator class defines
semantics for index columns of a particular datatype and a particular
index access method. Note that there can be multiple operator classes
for a given datatype/access method combination, thus supporting multiple
behaviors.
</para>
<para>
This patch includes a lot of minor cleanups to the SGML documentation, including: - replacing all the appropriate usages of <citetitle>PostgreSQL ...</citetitle> with &cite-user;, &cite-admin;, and so on - fix an omission in the EXECUTE documentation - add some more text to the EXPLAIN documentation - improve the PL/PgSQL RETURN NEXT documentation (more work to do here) - minor markup fixes Neil Conway
2003-01-19 01:13:31 +01:00
Operator classes are described at length in the &cite-programmer;.
Rewrite xindex.sgml for CREATE OPERATOR CLASS. catalogs.sgml finally contains descriptions of every single system table. Update 'complex' tutorial example too.
2002-07-30 07:24:56 +02:00
</para>
<table>
<title>pg_opclass Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>opcamid</entry>
<entry><type>oid</type></entry>
<entry>pg_am.oid</entry>
<entry>index access method opclass is for</entry>
</row>
<row>
<entry>opcname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>name of this opclass</entry>
</row>
<row>
<entry>opcnamespace</entry>
<entry><type>oid</type></entry>
<entry>pg_namespace.oid</entry>
<entry>namespace of this opclass</entry>
</row>
<row>
<entry>opcowner</entry>
<entry><type>int4</type></entry>
<entry>pg_shadow.usesysid</entry>
<entry>opclass owner</entry>
</row>
<row>
<entry>opcintype</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>type of input data for opclass</entry>
</row>
<row>
<entry>opcdefault</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>true if opclass is default for opcintype</entry>
</row>
<row>
<entry>opckeytype</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>type of index data, or zero if same as opcintype</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
The majority of the information defining an operator class is actually
not in its <structname>pg_opclass</structname> row, but in the associated
rows in <structname>pg_amop</structname> and
<structname>pg_amproc</structname>. Those rows are considered to be
part of the operator class definition --- this is not unlike the way
that a relation is defined by a single <structname>pg_class</structname>
row, plus associated rows in <structname>pg_attribute</structname> and
other tables.
</para>
</sect1>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
<sect1 id="catalog-pg-operator">
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<title>pg_operator</title>
<para>
This patch includes a lot of minor cleanups to the SGML documentation, including: - replacing all the appropriate usages of <citetitle>PostgreSQL ...</citetitle> with &cite-user;, &cite-admin;, and so on - fix an omission in the EXECUTE documentation - add some more text to the EXPLAIN documentation - improve the PL/PgSQL RETURN NEXT documentation (more work to do here) - minor markup fixes Neil Conway
2003-01-19 01:13:31 +01:00
See <command>CREATE OPERATOR</command> and the &cite-programmer;
for details on these operator parameters.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</para>
<table>
<title>pg_operator Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>oprname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Name of the operator</entry>
</row>
Operators live in namespaces. CREATE/DROP/COMMENT ON OPERATOR take qualified operator names directly, for example CREATE OPERATOR myschema.+ ( ... ). To qualify an operator name in an expression you need to write OPERATOR(myschema.+) (thanks to Peter for suggesting an escape hatch). I also took advantage of having to reformat pg_operator to fix something that'd been bugging me for a while: mergejoinable operators should have explicit links to the associated cross-data-type comparison operators, rather than hardwiring an assumption that they are named < and >.
2002-04-17 01:08:12 +02:00
<row>
<entry>oprnamespace</entry>
<entry><type>oid</type></entry>
<entry>pg_namespace.oid</entry>
<entry>
The OID of the namespace that contains this operator
</entry>
</row>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<row>
<entry>oprowner</entry>
<entry><type>int4</type></entry>
<entry>pg_shadow.usesysid</entry>
<entry>Owner (creator) of the operator</entry>
</row>
<row>
<entry>oprkind</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>
'b' = infix (<quote>both</quote>), 'l' = prefix
(<quote>left</quote>), 'r' = postfix (<quote>right</quote>)
</entry>
</row>
<row>
<entry>oprcanhash</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>This operator supports hash joins.</entry>
</row>
<row>
<entry>oprleft</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>Type of the left operand</entry>
</row>
<row>
<entry>oprright</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>Type of the right operand</entry>
</row>
<row>
<entry>oprresult</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>Type of the result</entry>
</row>
<row>
<entry>oprcom</entry>
<entry><type>oid</type></entry>
<entry>pg_operator.oid</entry>
<entry>Commutator of this operator, if any</entry>
</row>
<row>
<entry>oprnegate</entry>
<entry><type>oid</type></entry>
<entry>pg_operator.oid</entry>
Change to Negator.
2000-12-11 19:26:37 +01:00
<entry>Negator of this operator, if any</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>oprlsortop</entry>
<entry><type>oid</type></entry>
<entry>pg_operator.oid</entry>
<entry>
If this operator supports merge joins, the operator that sorts
Operators live in namespaces. CREATE/DROP/COMMENT ON OPERATOR take qualified operator names directly, for example CREATE OPERATOR myschema.+ ( ... ). To qualify an operator name in an expression you need to write OPERATOR(myschema.+) (thanks to Peter for suggesting an escape hatch). I also took advantage of having to reformat pg_operator to fix something that'd been bugging me for a while: mergejoinable operators should have explicit links to the associated cross-data-type comparison operators, rather than hardwiring an assumption that they are named < and >.
2002-04-17 01:08:12 +02:00
the type of the left-hand operand (<literal>L&lt;L</>)
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>oprrsortop</entry>
<entry><type>oid</type></entry>
<entry>pg_operator.oid</entry>
<entry>
If this operator supports merge joins, the operator that sorts
Operators live in namespaces. CREATE/DROP/COMMENT ON OPERATOR take qualified operator names directly, for example CREATE OPERATOR myschema.+ ( ... ). To qualify an operator name in an expression you need to write OPERATOR(myschema.+) (thanks to Peter for suggesting an escape hatch). I also took advantage of having to reformat pg_operator to fix something that'd been bugging me for a while: mergejoinable operators should have explicit links to the associated cross-data-type comparison operators, rather than hardwiring an assumption that they are named < and >.
2002-04-17 01:08:12 +02:00
the type of the right-hand operand (<literal>R&lt;R</>)
</entry>
</row>
<row>
<entry>oprltcmpop</entry>
<entry><type>oid</type></entry>
<entry>pg_operator.oid</entry>
<entry>
If this operator supports merge joins, the less-than operator that
compares the left and right operand types (<literal>L&lt;R</>)
</entry>
</row>
<row>
<entry>oprgtcmpop</entry>
<entry><type>oid</type></entry>
<entry>pg_operator.oid</entry>
<entry>
If this operator supports merge joins, the greater-than operator that
compares the left and right operand types (<literal>L&gt;R</>)
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>oprcode</entry>
<entry><type>regproc</type></entry>
Operators live in namespaces. CREATE/DROP/COMMENT ON OPERATOR take qualified operator names directly, for example CREATE OPERATOR myschema.+ ( ... ). To qualify an operator name in an expression you need to write OPERATOR(myschema.+) (thanks to Peter for suggesting an escape hatch). I also took advantage of having to reformat pg_operator to fix something that'd been bugging me for a while: mergejoinable operators should have explicit links to the associated cross-data-type comparison operators, rather than hardwiring an assumption that they are named < and >.
2002-04-17 01:08:12 +02:00
<entry>pg_proc.oid</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>Function that implements this operator</entry>
</row>
<row>
<entry>oprrest</entry>
<entry><type>regproc</type></entry>
Operators live in namespaces. CREATE/DROP/COMMENT ON OPERATOR take qualified operator names directly, for example CREATE OPERATOR myschema.+ ( ... ). To qualify an operator name in an expression you need to write OPERATOR(myschema.+) (thanks to Peter for suggesting an escape hatch). I also took advantage of having to reformat pg_operator to fix something that'd been bugging me for a while: mergejoinable operators should have explicit links to the associated cross-data-type comparison operators, rather than hardwiring an assumption that they are named < and >.
2002-04-17 01:08:12 +02:00
<entry>pg_proc.oid</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>Restriction selectivity estimation function for this operator</entry>
</row>
<row>
<entry>oprjoin</entry>
<entry><type>regproc</type></entry>
Operators live in namespaces. CREATE/DROP/COMMENT ON OPERATOR take qualified operator names directly, for example CREATE OPERATOR myschema.+ ( ... ). To qualify an operator name in an expression you need to write OPERATOR(myschema.+) (thanks to Peter for suggesting an escape hatch). I also took advantage of having to reformat pg_operator to fix something that'd been bugging me for a while: mergejoinable operators should have explicit links to the associated cross-data-type comparison operators, rather than hardwiring an assumption that they are named < and >.
2002-04-17 01:08:12 +02:00
<entry>pg_proc.oid</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry>Join selectivity estimation function for this operator</entry>
</row>
</tbody>
</tgroup>
</table>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<para>
Unused fields contain zeroes, for example oprleft is zero for a
prefix operator.
</para>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
</sect1>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
<sect1 id="catalog-pg-proc">
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<title>pg_proc</title>
<para>
This catalog stores information about functions (or procedures).
The description of <command>CREATE FUNCTION</command> and the
This patch includes a lot of minor cleanups to the SGML documentation, including: - replacing all the appropriate usages of <citetitle>PostgreSQL ...</citetitle> with &cite-user;, &cite-admin;, and so on - fix an omission in the EXECUTE documentation - add some more text to the EXPLAIN documentation - improve the PL/PgSQL RETURN NEXT documentation (more work to do here) - minor markup fixes Neil Conway
2003-01-19 01:13:31 +01:00
&cite-programmer; contain more information about the meaning of
some fields.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</para>
Restructure representation of aggregate functions so that they have pg_proc entries, per pghackers discussion. This fixes aggregates to live in namespaces, and also simplifies/speeds up lookup in parse_func.c. Also, add a 'proimplicit' flag to pg_proc that controls whether a type coercion function may be invoked implicitly, or only explicitly. The current settings of these flags are more permissive than I would like, but we will need to debate and refine the behavior; for now, I avoided breaking regression tests as much as I could.
2002-04-11 22:00:18 +02:00
<para>
The table contains data for aggregate functions as well as plain functions.
If <structfield>proisagg</structfield> is true, there should be a matching
row in <structname>pg_aggregate</structname>.
</para>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<table>
<title>pg_proc Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>proname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Name of the function</entry>
</row>
Divide functions into three volatility classes (immutable, stable, and volatile), rather than the old cachable/noncachable distinction. This allows indexscan optimizations in many places where we formerly didn't. Also, add a pronamespace column to pg_proc (it doesn't do anything yet, however).
2002-04-05 02:31:36 +02:00
<row>
<entry>pronamespace</entry>
<entry><type>oid</type></entry>
<entry>pg_namespace.oid</entry>
<entry>
The OID of the namespace that contains this function
</entry>
</row>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<row>
<entry>proowner</entry>
<entry><type>int4</type></entry>
<entry>pg_shadow.usesysid</entry>
<entry>Owner (creator) of the function</entry>
</row>
<row>
<entry>prolang</entry>
<entry><type>oid</type></entry>
<entry>pg_language.oid</entry>
<entry>Implementation language or call interface of this function</entry>
</row>
<row>
Restructure representation of aggregate functions so that they have pg_proc entries, per pghackers discussion. This fixes aggregates to live in namespaces, and also simplifies/speeds up lookup in parse_func.c. Also, add a 'proimplicit' flag to pg_proc that controls whether a type coercion function may be invoked implicitly, or only explicitly. The current settings of these flags are more permissive than I would like, but we will need to debate and refine the behavior; for now, I avoided breaking regression tests as much as I could.
2002-04-11 22:00:18 +02:00
<entry>proisagg</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry><type>bool</type></entry>
<entry></entry>
Restructure representation of aggregate functions so that they have pg_proc entries, per pghackers discussion. This fixes aggregates to live in namespaces, and also simplifies/speeds up lookup in parse_func.c. Also, add a 'proimplicit' flag to pg_proc that controls whether a type coercion function may be invoked implicitly, or only explicitly. The current settings of these flags are more permissive than I would like, but we will need to debate and refine the behavior; for now, I avoided breaking regression tests as much as I could.
2002-04-11 22:00:18 +02:00
<entry>Function is an aggregate function</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<entry>prosecdef</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<entry><type>bool</type></entry>
<entry></entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<entry>Function is a security definer (i.e., a <quote>setuid</>
function)</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>proisstrict</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
Function returns null if any call argument is null. In that
case the function won't actually be called at all. Functions
that are not <quote>strict</quote> must be prepared to handle
null inputs.
</entry>
</row>
Restructure representation of aggregate functions so that they have pg_proc entries, per pghackers discussion. This fixes aggregates to live in namespaces, and also simplifies/speeds up lookup in parse_func.c. Also, add a 'proimplicit' flag to pg_proc that controls whether a type coercion function may be invoked implicitly, or only explicitly. The current settings of these flags are more permissive than I would like, but we will need to debate and refine the behavior; for now, I avoided breaking regression tests as much as I could.
2002-04-11 22:00:18 +02:00
<row>
<entry>proretset</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>Function returns a set (ie, multiple values of the specified
data type)</entry>
</row>
Divide functions into three volatility classes (immutable, stable, and volatile), rather than the old cachable/noncachable distinction. This allows indexscan optimizations in many places where we formerly didn't. Also, add a pronamespace column to pg_proc (it doesn't do anything yet, however).
2002-04-05 02:31:36 +02:00
<row>
<entry>provolatile</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>
<structfield>provolatile</structfield> tells whether the function's
result depends only on its input arguments, or is affected by outside
factors.
It is <literal>i</literal> for <quote>immutable</> functions,
which always deliver the same result for the same inputs.
It is <literal>s</literal> for <quote>stable</> functions,
whose results (for fixed inputs) do not change within a scan.
It is <literal>v</literal> for <quote>volatile</> functions,
whose results may change at any time. (Use <literal>v</literal> also
for functions with side-effects, so that calls to them cannot get
optimized away.)
</entry>
</row>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<row>
<entry>pronargs</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>Number of arguments</entry>
</row>
<row>
<entry>prorettype</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<entry>Data type of the return value</entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>proargtypes</entry>
<entry><type>oidvector</type></entry>
<entry>pg_type.oid</entry>
<entry>A vector with the data types of the function arguments</entry>
</row>
<row>
<entry>prosrc</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry>
This tells the function handler how to invoke the function. It
might be the actual source code of the function for interpreted
languages, a link symbol, a file name, or just about anything
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
else, depending on the implementation language/call convention.
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>probin</entry>
<entry><type>bytea</type></entry>
<entry></entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<entry>Additional information about how to invoke the function.
Again, the interpretation is language-specific.
</entry>
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</row>
Privileges on functions and procedural languages
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<row>
<entry>proacl</entry>
<entry><type>aclitem[]</type></entry>
<entry></entry>
<entry>Access permissions</entry>
</row>
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</tbody>
</tgroup>
</table>
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<para>
Currently, prosrc contains the function's C-language name (link symbol)
for compiled functions, both built-in and dynamically loaded. For all
other language types, prosrc contains the function's source text.
</para>
<para>
Currently, probin is unused except for dynamically-loaded C functions,
for which it gives the name of the shared library file containing the
function.
</para>
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</sect1>
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<sect1 id="catalog-pg-rewrite">
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<title>pg_rewrite</title>
<para>
This system catalog stores rewrite rules for tables and views.
</para>
<table>
<title>pg_rewrite Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>rulename</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Rule name</entry>
</row>
<row>
<entry>ev_class</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>The table this rule is for</entry>
</row>
<row>
<entry>ev_attr</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>The column this rule is for (currently, always zero to
indicate the whole table)</entry>
</row>
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<row>
<entry>ev_type</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>Event type that the rule is for: '1' = SELECT,
'2' = UPDATE, '3' = INSERT, '4' = DELETE</entry>
</row>
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<row>
<entry>is_instead</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>True if the rule is an INSTEAD rule</entry>
</row>
<row>
<entry>ev_qual</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry>Expression tree (in the form of a nodeToString representation)
for the rule's qualifying condition</entry>
</row>
<row>
<entry>ev_action</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry>Query tree (in the form of a nodeToString representation)
for the rule's action</entry>
</row>
</tbody>
</tgroup>
</table>
<note>
<para>
<structname>pg_class</structname>.<structfield>relhasrules</structfield>
must be true if a table has any rules in this catalog.
</para>
</note>
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</sect1>
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<sect1 id="catalog-pg-shadow">
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<title>pg_shadow</title>
<para>
<structname>pg_shadow</structname> contains information about
database users. The name stems from the fact that this table
should not be readable by the public since it contains passwords.
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<structname>pg_user</structname> is a publicly readable view on
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<structname>pg_shadow</structname> that blanks out the password field.
</para>
<para>
This patch includes a lot of minor cleanups to the SGML documentation, including: - replacing all the appropriate usages of <citetitle>PostgreSQL ...</citetitle> with &cite-user;, &cite-admin;, and so on - fix an omission in the EXECUTE documentation - add some more text to the EXPLAIN documentation - improve the PL/PgSQL RETURN NEXT documentation (more work to do here) - minor markup fixes Neil Conway
2003-01-19 01:13:31 +01:00
The &cite-admin; contains detailed information about user and
permission management.
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</para>
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<para>
Because user identities are cluster-wide,
<structname>pg_shadow</structname>
is shared across all databases of a cluster: there is only one
copy of <structname>pg_shadow</structname> per cluster, not
one per database.
</para>
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<table>
<title>pg_shadow Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>usename</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>User name</entry>
</row>
<row>
<entry>usesysid</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>User id (arbitrary number used to reference this user)</entry>
</row>
<row>
<entry>usecreatedb</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>User may create databases</entry>
</row>
<row>
<entry>usesuper</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>User is a superuser</entry>
</row>
<row>
<entry>usecatupd</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
User may update system catalogs. (Even a superuser may not do
this unless this attribute is true.)
</entry>
</row>
<row>
<entry>passwd</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry>Password</entry>
</row>
<row>
<entry>valuntil</entry>
<entry><type>abstime</type></entry>
<entry></entry>
<entry>Account expiry time (only used for password authentication)</entry>
</row>
User and database-specific session defaults for run-time configuration variables. New commands ALTER DATABASE ... SET and ALTER USER ... SET.
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<row>
<entry>useconfig</entry>
<entry><type>text[]</type></entry>
<entry></entry>
<entry>Session defaults for run-time configuration variables</entry>
</row>
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</tbody>
</tgroup>
</table>
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</sect1>
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<sect1 id="catalog-pg-statistic">
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
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<title>pg_statistic</title>
<para>
<structname>pg_statistic</structname> stores statistical data about
the contents of the database. Entries are created by
<command>ANALYZE</command> and subsequently used by the query planner.
There is one entry for each table column that has been analyzed.
Note that all the statistical data is inherently approximate,
even assuming that it is up-to-date.
</para>
<para>
Since different kinds of statistics may be appropriate for different
kinds of data, <structname>pg_statistic</structname> is designed not
to assume very much about what sort of statistics it stores. Only
extremely general statistics (such as NULL-ness) are given dedicated
columns in <structname>pg_statistic</structname>. Everything else
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is stored in <quote>slots</quote>, which are groups of associated columns whose
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
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content is identified by a code number in one of the slot's columns.
For more information see
<filename>src/include/catalog/pg_statistic.h</filename>.
</para>
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<para>
<structname>pg_statistic</structname> should not be readable by the
public, since even statistical information about a table's contents
may be considered sensitive. (Example: minimum and maximum values
of a salary column might be quite interesting.)
<structname>pg_stats</structname> is a publicly readable view on
<structname>pg_statistic</structname> that only exposes information
about those tables that are readable by the current user.
<structname>pg_stats</structname> is also designed to present the
information in a more readable format than the underlying
<structname>pg_statistic</structname> table --- at the cost that
its schema must be extended whenever new slot types are added.
</para>
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
<table>
<title>pg_statistic Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>starelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>The table that the described column belongs to</entry>
</row>
<row>
<entry>staattnum</entry>
<entry><type>int2</type></entry>
<entry>pg_attribute.attnum</entry>
<entry>The number of the described column</entry>
</row>
<row>
<entry>stanullfrac</entry>
<entry><type>float4</type></entry>
<entry></entry>
<entry>The fraction of the column's entries that are NULL</entry>
</row>
<row>
<entry>stawidth</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry>The average stored width, in bytes, of non-NULL entries</entry>
</row>
<row>
<entry>stadistinct</entry>
<entry><type>float4</type></entry>
<entry></entry>
<entry>The number of distinct non-NULL data values in the column.
A value greater than zero is the actual number of distinct values.
A value less than zero is the negative of a fraction of the number
of rows in the table (for example, a column in which values appear about
twice on the average could be represented by stadistinct = -0.5).
A zero value means the number of distinct values is unknown.
</entry>
</row>
<row>
<entry>stakindN</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>A code number indicating the kind of statistics stored in the Nth
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<quote>slot</quote> of the <structname>pg_statistic</structname> row.
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
</entry>
</row>
<row>
<entry>staopN</entry>
<entry><type>oid</type></entry>
<entry>pg_operator.oid</entry>
<entry>An operator used to derive the statistics stored in the
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Nth <quote>slot</quote>. For example, a histogram slot would show the <literal>&lt;</literal>
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
operator that defines the sort order of the data.
</entry>
</row>
<row>
<entry>stanumbersN</entry>
<entry><type>float4[]</type></entry>
<entry></entry>
<entry>Numerical statistics of the appropriate kind for the Nth
Replace ASCII-quotes with proper markup.
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<quote>slot</quote>, or NULL if the slot kind does not involve numerical values.
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
</entry>
</row>
<row>
<entry>stavaluesN</entry>
<entry><type>text[]</type></entry>
<entry></entry>
<entry>Column data values of the appropriate kind for the Nth
Replace ASCII-quotes with proper markup.
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<quote>slot</quote>, or NULL if the slot kind does not store any data values.
Spell checking and markup additions
2002-03-22 20:20:45 +01:00
For data-type independence, all column data values are converted
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
to external textual form and stored as TEXT datums.
</entry>
</row>
</tbody>
</tgroup>
</table>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
</sect1>
Rewrite of planner statistics-gathering code. ANALYZE is now available as a separate statement (though it can still be invoked as part of VACUUM, too). pg_statistic redesigned to be more flexible about what statistics are stored. ANALYZE now collects a list of several of the most common values, not just one, plus a histogram (not just the min and max values). Random sampling is used to make the process reasonably fast even on very large tables. The number of values and histogram bins collected is now user-settable via an ALTER TABLE command. There is more still to do; the new stats are not being used everywhere they could be in the planner. But the remaining changes for this project should be localized, and the behavior is already better than before. A not-very-related change is that sorting now makes use of btree comparison routines if it can find one, rather than invoking '<' twice.
2001-05-07 02:43:27 +02:00
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
<sect1 id="catalog-pg-trigger">
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<title>pg_trigger</title>
<para>
This system catalog stores triggers on tables. See under
<command>CREATE TRIGGER</command> for more information.
</para>
<table>
<title>pg_trigger Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>tgrelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>The table this trigger is on</entry>
</row>
<row>
<entry>tgname</entry>
<entry><type>name</type></entry>
<entry></entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<entry>Trigger name (must be unique among triggers of same table)</entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
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</row>
<row>
<entry>tgfoid</entry>
<entry><type>oid</type></entry>
<entry>pg_proc.oid</entry>
<entry>The function to be called</entry>
</row>
<row>
<entry>tgtype</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>Bitmask identifying trigger conditions</entry>
</row>
<row>
<entry>tgenabled</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>True if trigger is enabled (not presently checked everywhere
it should be, so disabling a trigger by setting this false does not
work reliably)</entry>
</row>
<row>
<entry>tgisconstraint</entry>
<entry><type>bool</type></entry>
<entry></entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<entry>True if trigger implements an RI constraint</entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
</row>
<row>
<entry>tgconstrname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>RI constraint name</entry>
</row>
<row>
<entry>tgconstrrelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>The table referenced by an RI constraint</entry>
</row>
<row>
<entry>tgdeferrable</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>True if deferrable</entry>
</row>
<row>
<entry>tginitdeferred</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>True if initially deferred</entry>
</row>
<row>
<entry>tgnargs</entry>
<entry><type>int2</type></entry>
<entry></entry>
<entry>Number of argument strings passed to trigger function</entry>
</row>
<row>
<entry>tgattr</entry>
<entry><type>int2vector</type></entry>
<entry></entry>
<entry>Currently unused</entry>
</row>
<row>
<entry>tgargs</entry>
<entry><type>bytea</type></entry>
<entry></entry>
<entry>Argument strings to pass to trigger, each null-terminated</entry>
</row>
</tbody>
</tgroup>
</table>
<note>
<para>
<structname>pg_class</structname>.<structfield>reltriggers</structfield>
needs to match up with the entries in this table.
</para>
</note>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
</sect1>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
<sect1 id="catalog-pg-type">
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<title>pg_type</title>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<para>
Spell checking and markup additions
2002-03-22 20:20:45 +01:00
This catalog stores information about data types. Scalar types
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
(<quote>base types</>) are created with <command>CREATE TYPE</command>.
Update info about relkind and pg_type entries for composite-types patch.
2002-08-28 17:02:55 +02:00
A complex type is automatically created for each table in the database, to
Code review for DOMAIN patch.
2002-03-20 20:45:13 +01:00
represent the row structure of the table. It is also possible to create
Update info about relkind and pg_type entries for composite-types patch.
2002-08-28 17:02:55 +02:00
complex types with <command>CREATE TYPE AS</command>, and
Code review for DOMAIN patch.
2002-03-20 20:45:13 +01:00
derived types with <command>CREATE DOMAIN</command>.
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
</para>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<table>
<title>pg_type Columns</title>
<tgroup cols=4>
<thead>
<row>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>typname</entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Data type name</entry>
</row>
pg_type has a typnamespace column; system now supports creating types in different namespaces. Also, cleanup work on relation namespace support: drop, alter, rename commands work for tables in non-default namespaces.
2002-03-29 20:06:29 +01:00
<row>
<entry>typnamespace</entry>
<entry><type>oid</type></entry>
<entry>pg_namespace.oid</entry>
<entry>
The OID of the namespace that contains this type
</entry>
</row>
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<row>
<entry>typowner</entry>
<entry><type>int4</type></entry>
<entry>pg_shadow.usesysid</entry>
<entry>Owner (creator) of the type</entry>
</row>
<row>
<entry>typlen</entry>
<entry><type>int2</type></entry>
<entry></entry>
The cstring datatype can now be copied, passed around, etc. The typlen value '-2' is used to indicate a variable-width type whose width is computed as strlen(datum)+1. Everything that looks at typlen is updated except for array support, which Joe Conway is working on; at the moment it wouldn't work to try to create an array of cstring.
2002-08-24 17:00:47 +02:00
<entry>
For a fixed-size type, <structfield>typlen</structfield> is the number
of bytes in the internal representation of the type. But for a
variable-length type, <structfield>typlen</structfield> is negative.
-1 indicates a <quote>varlena</> type (one that has a length word),
-2 indicates a null-terminated C string.
</entry>
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</row>
<row>
<entry>typbyval</entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>
<structfield>typbyval</structfield> determines whether internal
routines pass a value of this type by value or by reference.
Only <type>char</type>, <type>short</type>, and
<type>int</type> equivalent items can be passed by value, so if
Deprecate 'current' for date/time input. Fix up references to "PostgreSQL" rather than "Postgres". Was roughly evenly split between the two before. ref/ files not yet done.
2001-11-21 06:53:41 +01:00
the type is not 1, 2, or 4 bytes long,
<productname>PostgreSQL</> does not have
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the option of passing by value and so
<structfield>typbyval</structfield> had better be false.
Variable-length types are always passed by reference. Note that
<structfield>typbyval</structfield> can be false even if the
length would allow pass-by-value; this is currently true for
type <type>float4</type>, for example.
</entry>
</row>
<row>
<entry>typtype</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry>
<structfield>typtype</structfield> is <literal>b</literal> for
Code review for DOMAIN patch.
2002-03-20 20:45:13 +01:00
a base type, <literal>c</literal> for a complex type (i.e.,
Preliminary code review for anonymous-composite-types patch: fix breakage of functions returning domain types, update documentation for typtype, move get_typtype to lsyscache.c (actually, resurrect the old version), add defense against creating pseudo-typed table columns, fix some bogus list-parsing in grammar. Issues remain with respect to alias handling and type checking; Joe is on those.
2002-08-05 04:30:50 +02:00
a table's row type), <literal>d</literal> for a derived type (i.e.,
a domain), or <literal>p</literal> for a pseudo-type. See also
<structfield>typrelid</structfield>
Code review for DOMAIN patch.
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and <structfield>typbasetype</structfield>.
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</entry>
</row>
<row>
<entry>typisdefined</entry>
<entry><type>bool</type></entry>
<entry></entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
<entry>True if the type is defined, false if this is a placeholder
entry for a not-yet-defined type. When typisdefined is false,
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
nothing except the type name, namespace, and OID can be relied on.
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
</entry>
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</row>
<row>
<entry>typdelim</entry>
<entry><type>char</type></entry>
<entry></entry>
Clean up wrong, misleading, or obsolete documentation about array types, particularly in the CREATE TYPE reference page. Fix some other errors in the CREATE TYPE page, too.
2001-11-03 22:42:47 +01:00
<entry>Character that separates two values of this type when parsing
array input. Note that the delimiter is associated with the array
Spell checking and markup additions
2002-03-22 20:20:45 +01:00
element data type, not the array data type.</entry>
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</row>
<row>
<entry>typrelid</entry>
<entry><type>oid</type></entry>
<entry>pg_class.oid</entry>
<entry>
Add note about pg_stats to pg_statistic entry; add sections for pg_largeobject, pg_listener, pg_rewrite, pg_trigger; miscellaneous small improvements.
2001-10-16 00:47:47 +02:00
If this is a complex type (see
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<structfield>typtype</structfield>), then this field points to
Update info about relkind and pg_type entries for composite-types patch.
2002-08-28 17:02:55 +02:00
the <structname>pg_class</structname> entry that defines the
corresponding table. (For a free-standing composite type, the
<structname>pg_class</structname> entry doesn't really represent
a table, but it is needed anyway for the type's
<structname>pg_attribute</structname> entries to link to.)
Code review for DOMAIN patch.
2002-03-20 20:45:13 +01:00
Zero for non-complex types.
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2000-11-29 21:15:59 +01:00
</entry>
</row>
<row>
<entry>typelem</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry>
If <structfield>typelem</structfield> is not 0 then it
identifies another row in <structname>pg_type</structname>.
The current type can then be subscripted like an array yielding
Clean up wrong, misleading, or obsolete documentation about array types, particularly in the CREATE TYPE reference page. Fix some other errors in the CREATE TYPE page, too.
2001-11-03 22:42:47 +01:00
values of type <structfield>typelem</structfield>. A
<quote>true</quote> array type is variable length
(<structfield>typlen</structfield> = -1),
but some fixed-length (<structfield>typlen</structfield> &gt; 0) types
also have nonzero <structfield>typelem</structfield>, for example
<type>name</type> and <type>oidvector</type>.
If a fixed-length type has a <structfield>typelem</structfield> then
its internal representation must be N values of the
Spell checking and markup additions
2002-03-22 20:20:45 +01:00
<structfield>typelem</structfield> data type with no other data.
Clean up wrong, misleading, or obsolete documentation about array types, particularly in the CREATE TYPE reference page. Fix some other errors in the CREATE TYPE page, too.
2001-11-03 22:42:47 +01:00
Variable-length array types have a header defined by the array
subroutines.
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</entry>
</row>
<row>
<entry>typinput</entry>
<entry><type>regproc</type></entry>
Operators live in namespaces. CREATE/DROP/COMMENT ON OPERATOR take qualified operator names directly, for example CREATE OPERATOR myschema.+ ( ... ). To qualify an operator name in an expression you need to write OPERATOR(myschema.+) (thanks to Peter for suggesting an escape hatch). I also took advantage of having to reformat pg_operator to fix something that'd been bugging me for a while: mergejoinable operators should have explicit links to the associated cross-data-type comparison operators, rather than hardwiring an assumption that they are named < and >.
2002-04-17 01:08:12 +02:00
<entry>pg_proc.oid</entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<entry>Input conversion function</entry>
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2000-11-29 21:15:59 +01:00
</row>
<row>
<entry>typoutput</entry>
<entry><type>regproc</type></entry>
Operators live in namespaces. CREATE/DROP/COMMENT ON OPERATOR take qualified operator names directly, for example CREATE OPERATOR myschema.+ ( ... ). To qualify an operator name in an expression you need to write OPERATOR(myschema.+) (thanks to Peter for suggesting an escape hatch). I also took advantage of having to reformat pg_operator to fix something that'd been bugging me for a while: mergejoinable operators should have explicit links to the associated cross-data-type comparison operators, rather than hardwiring an assumption that they are named < and >.
2002-04-17 01:08:12 +02:00
<entry>pg_proc.oid</entry>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
<entry>Output conversion function</entry>
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</row>
<row>
<entry>typalign</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry><para>
<structfield>typalign</structfield> is the alignment required
when storing a value of this type. It applies to storage on
disk as well as most representations of the value inside
Deprecate 'current' for date/time input. Fix up references to "PostgreSQL" rather than "Postgres". Was roughly evenly split between the two before. ref/ files not yet done.
2001-11-21 06:53:41 +01:00
<productname>PostgreSQL</>.
Replace pg_attribute.attisinherited with attislocal and attinhcount columns, to allow more correct behavior in multiple-inheritance cases. Patch by Alvaro Herrera, review by Tom Lane.
2002-09-22 21:42:52 +02:00
When multiple values are stored consecutively, such
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
as in the representation of a complete row on disk, padding is
inserted before a datum of this type so that it begins on the
specified boundary. The alignment reference is the beginning
of the first datum in the sequence.
</para><para>
Possible values are:
<itemizedlist>
<listitem>
minor copy editing
2001-03-25 00:03:26 +01:00
<para>'c' = CHAR alignment, i.e., no alignment needed.</para>
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</listitem>
<listitem>
<para>'s' = SHORT alignment (2 bytes on most machines).</para>
</listitem>
<listitem>
<para>'i' = INT alignment (4 bytes on most machines).</para>
</listitem>
<listitem>
<para>'d' = DOUBLE alignment (8 bytes on many machines, but by no means all).</para>
</listitem>
</itemizedlist>
</para><note>
<para>
For types used in system tables, it is critical that the size
and alignment defined in <structname>pg_type</structname>
agree with the way that the compiler will lay out the field in
a struct representing a table row.
</para>
</note></entry>
</row>
<row>
<entry>typstorage</entry>
<entry><type>char</type></entry>
<entry></entry>
<entry><para>
The cstring datatype can now be copied, passed around, etc. The typlen value '-2' is used to indicate a variable-width type whose width is computed as strlen(datum)+1. Everything that looks at typlen is updated except for array support, which Joe Conway is working on; at the moment it wouldn't work to try to create an array of cstring.
2002-08-24 17:00:47 +02:00
<structfield>typstorage</structfield> tells for varlena
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
types (those with <structfield>typlen</structfield> = -1) if
the type is prepared for toasting and what the default strategy
for attributes of this type should be.
Possible values are
<itemizedlist>
<listitem>
<para>'p': Value must always be stored plain.</para>
</listitem>
<listitem>
<para>
'e': Value can be stored in a <quote>secondary</quote>
relation (if relation has one, see
<structname>pg_class</structname>.<structfield>reltoastrelid</structfield>).
</para>
</listitem>
<listitem>
<para>'m': Value can be stored compressed inline.</para>
</listitem>
<listitem>
<para>'x': Value can be stored compressed inline or in <quote>secondary</quote>.</para>
</listitem>
</itemizedlist>
Note that 'm' fields can also be moved out to secondary
storage, but only as a last resort ('e' and 'x' fields are
moved first).
</para></entry>
</row>
Add DOMAIN support. Includes manual pages and regression tests, from Rod Taylor.
2002-03-19 03:18:25 +01:00
<row>
Code review for DOMAIN patch.
2002-03-20 20:45:13 +01:00
<entry>typnotnull</entry>
<entry><type>bool</type></entry>
Add DOMAIN support. Includes manual pages and regression tests, from Rod Taylor.
2002-03-19 03:18:25 +01:00
<entry></entry>
<entry><para>
Code review for DOMAIN patch.
2002-03-20 20:45:13 +01:00
<structfield>typnotnull</structfield> represents a NOT NULL
constraint on a type. Presently used for domains only.
Add DOMAIN support. Includes manual pages and regression tests, from Rod Taylor.
2002-03-19 03:18:25 +01:00
</para></entry>
</row>
Code review for DOMAIN patch.
2002-03-20 20:45:13 +01:00
<row>
<entry>typbasetype</entry>
<entry><type>oid</type></entry>
<entry>pg_type.oid</entry>
<entry><para>
If this is a derived type (see <structfield>typtype</structfield>),
then <structfield>typbasetype</structfield> identifies
the type that this one is based on. Zero if not a derived type.
</para></entry>
</row>
Add DOMAIN support. Includes manual pages and regression tests, from Rod Taylor.
2002-03-19 03:18:25 +01:00
<row>
Code review for DOMAIN patch.
2002-03-20 20:45:13 +01:00
<entry>typtypmod</entry>
<entry><type>int4</type></entry>
Add DOMAIN support. Includes manual pages and regression tests, from Rod Taylor.
2002-03-19 03:18:25 +01:00
<entry></entry>
<entry><para>
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
Domains use <structfield>typtypmod</structfield> to record the typmod
to be applied to their base type (-1 if base type does not use a
typmod). -1 if this type is not a domain.
</para></entry>
Code review for DOMAIN patch.
2002-03-20 20:45:13 +01:00
</row>
<row>
<entry>typndims</entry>
<entry><type>int4</type></entry>
<entry></entry>
<entry><para>
<structfield>typndims</structfield> is the number of array dimensions
Update some obsolete comments and column descriptions.
2002-09-24 23:26:44 +02:00
for a domain that is an array (that is, typbasetype is an array type;
the domain's typelem will match the base type's typelem).
Zero for non-domains and non-array domains.
Add DOMAIN support. Includes manual pages and regression tests, from Rod Taylor.
2002-03-19 03:18:25 +01:00
</para></entry>
</row>
<row>
<entry>typdefaultbin</entry>
<entry><type>text</type></entry>
<entry></entry>
<entry><para>
Code review for DOMAIN patch.
2002-03-20 20:45:13 +01:00
If <structfield>typdefaultbin</> is not NULL, it is the nodeToString
representation of a default expression for the type. Currently this is
only used for domains.
Add DOMAIN support. Includes manual pages and regression tests, from Rod Taylor.
2002-03-19 03:18:25 +01:00
</para></entry>
</row>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
<row>
<entry>typdefault</entry>
<entry><type>text</type></entry>
<entry></entry>
Fix handling of pg_type.typdefault per bug report from Dave Blasby. If there's anyone out there who's actually using datatype-defined default values, this will be an incompatible change in behavior ... but the old behavior was so broken that I doubt anyone was using it.
2001-09-06 04:07:42 +02:00
<entry><para>
Code review for DOMAIN patch.
2002-03-20 20:45:13 +01:00
<structfield>typdefault</> is NULL if the type has no associated
default value. If <structfield>typdefaultbin</> is not NULL,
<structfield>typdefault</> must contain a human-readable version of the
default expression represented by <structfield>typdefaultbin</>. If
<structfield>typdefaultbin</> is NULL and <structfield>typdefault</> is
not, then <structfield>typdefault</> is the external representation of
the type's default value, which may be fed to the type's input
converter to produce a constant.
Fix handling of pg_type.typdefault per bug report from Dave Blasby. If there's anyone out there who's actually using datatype-defined default values, this will be an incompatible change in behavior ... but the old behavior was so broken that I doubt anyone was using it.
2001-09-06 04:07:42 +02:00
</para></entry>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</row>
</tbody>
</tgroup>
</table>
Use <sect1> rather than <section> to simplify formatting.
2001-11-09 00:44:01 +01:00
</sect1>
Rewrite system catalog documentation man page in DocBook with more recent information.
2000-11-29 21:15:59 +01:00
</chapter>
Deprecate 'current' for date/time input. Fix up references to "PostgreSQL" rather than "Postgres". Was roughly evenly split between the two before. ref/ files not yet done.
2001-11-21 06:53:41 +01:00
<!-- Keep this comment at the end of the file
Local variables:
mode:sgml
sgml-omittag:nil
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-tabs-mode:nil
sgml-indent-data:t
sgml-parent-document:nil
sgml-default-dtd-file:"./reference.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:("/usr/share/sgml/catalog")
sgml-local-ecat-files:nil
End:
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