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Postgres FD Implementation
Commit 816cbb59 authored by Alvaro Herrera's avatar Alvaro Herrera
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Adjust some glossary terms 

Mostly in response to Jürgen Purtz critique of previous definitions,
though I added many other changes.

Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: default avatarJürgen Purtz <juergen@purtz.de>
Reviewed-by: default avatarJustin Pryzby <pryzby@telsasoft.com>
Reviewed-by: default avatarErik Rijkers <er@xs4all.nl>
Discussion: https://postgr.es/m/c1e06008-2132-30f4-9b38-877e8683d418@purtz.de
parent be14f884
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doc/src/sgml/glossary.sgml
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...@@ -23,7 +23,7 @@ ...@@ -23,7 +23,7 @@
</glossentry> </glossentry>
<glossentry id="glossary-aggregate"> <glossentry id="glossary-aggregate">
<glossterm>Aggregate function</glossterm> <glossterm>Aggregate function (routine)</glossterm>
<glossdef> <glossdef>
<para> <para>
A <glossterm linkend="glossary-function">function</glossterm> that A <glossterm linkend="glossary-function">function</glossterm> that
...@@ -39,6 +39,11 @@ ...@@ -39,6 +39,11 @@
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry>
<glossterm>Analytic function</glossterm>
<glosssee otherterm="glossary-window-function" />
</glossentry>
<glossentry id="glossary-analyze"> <glossentry id="glossary-analyze">
<glossterm>Analyze (operation)</glossterm> <glossterm>Analyze (operation)</glossterm>
<glossdef> <glossdef>
...@@ -54,14 +59,13 @@ ...@@ -54,14 +59,13 @@
(Don't confuse this term with the <literal>ANALYZE</literal> option (Don't confuse this term with the <literal>ANALYZE</literal> option
to the <xref linkend="sql-explain"/> command.) to the <xref linkend="sql-explain"/> command.)
</para> </para>
<para>
For more information, see
<xref linkend="sql-analyze"/>.
</para>
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry>
<glossterm>Analytic function</glossterm>
<glosssee otherterm="glossary-window-function" />
</glossentry>
<glossentry id="glossary-atomic"> <glossentry id="glossary-atomic">
<glossterm>Atomic</glossterm> <glossterm>Atomic</glossterm>
<glossdef> <glossdef>
...@@ -98,8 +102,7 @@ ...@@ -98,8 +102,7 @@
<glossdef> <glossdef>
<para> <para>
An element with a certain name and data type found within a An element with a certain name and data type found within a
<glossterm linkend="glossary-tuple">tuple</glossterm> or <glossterm linkend="glossary-tuple">tuple</glossterm>.
<glossterm linkend="glossary-table">table</glossterm>.
</para> </para>
</glossdef> </glossdef>
</glossentry> </glossentry>
...@@ -389,40 +392,33 @@ ...@@ -389,40 +392,33 @@
<glosssee otherterm="glossary-data-directory" /> <glosssee otherterm="glossary-data-directory" />
</glossentry> </glossentry>
<glossentry id="glossary-data-directory"> <glossentry id="glossary-database">
<glossterm>Data directory</glossterm> <glossterm>Database</glossterm>
<glossdef> <glossdef>
<para> <para>
The base directory on the filesystem of a A named collection of
<glossterm linkend="glossary-server">server</glossterm> that contains all <glossterm linkend="glossary-sql-object">local SQL objects</glossterm>.
data files and subdirectories associated with an
<glossterm linkend="glossary-instance">instance</glossterm> (with the
exception of <glossterm linkend="glossary-tablespace">tablespaces</glossterm>).
The environment variable <literal>PGDATA</literal> is commonly used to
refer to the
<glossterm linkend="glossary-data-directory">data directory</glossterm>.
</para>
<para>
An <glossterm linkend="glossary-instance">instance</glossterm>'s storage
space comprises the data directory plus any additional tablespaces.
</para> </para>
<para> <para>
For more information, see For more information, see
<xref linkend="storage-file-layout"/>. <xref linkend="manage-ag-overview"/>.
</para> </para>
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry id="glossary-database"> <glossentry id="glossary-db-cluster">
<glossterm>Database</glossterm> <glossterm>Database cluster</glossterm>
<glossdef> <glossdef>
<para> <para>
A named collection of A collection of databases and global SQL objects,
<glossterm linkend="glossary-sql-object">SQL objects</glossterm>. and their common static and dynamic metadata.
Sometimes referred to as a
<firstterm>cluster</firstterm>.
</para> </para>
<para> <para>
For more information, see In <productname>PostgreSQL</productname>, the term
<xref linkend="manage-ag-overview"/>. <firstterm>cluster</firstterm> is also sometimes used to refer to an instance.
(Don't confuse this term with the SQL command <command>CLUSTER</command>.)
</para> </para>
</glossdef> </glossdef>
</glossentry> </glossentry>
...@@ -432,6 +428,31 @@ ...@@ -432,6 +428,31 @@
<glosssee otherterm="glossary-instance" /> <glosssee otherterm="glossary-instance" />
</glossentry> </glossentry>
<glossentry id="glossary-data-directory">
<glossterm>Data directory</glossterm>
<glossdef>
<para>
The base directory on the filesystem of a
<glossterm linkend="glossary-server">server</glossterm> that contains all
data files and subdirectories associated with a
<glossterm linkend="glossary-db-cluster">database cluster</glossterm>
(with the exception of
<glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
and optionally <glossterm linkend="glossary-wal">WAL</glossterm>).
The environment variable <literal>PGDATA</literal> is commonly used to
refer to the data directory.
</para>
<para>
A <glossterm linkend="glossary-db-cluster">cluster</glossterm>'s storage
space comprises the data directory plus any additional tablespaces.
</para>
<para>
For more information, see
<xref linkend="storage-file-layout"/>.
</para>
</glossdef>
</glossentry>
<glossentry id="glossary-data-page"> <glossentry id="glossary-data-page">
<glossterm>Data page</glossterm> <glossterm>Data page</glossterm>
<glossdef> <glossdef>
...@@ -578,7 +599,7 @@ ...@@ -578,7 +599,7 @@
</glossentry> </glossentry>
<glossentry id="glossary-foreign-table"> <glossentry id="glossary-foreign-table">
<glossterm>Foreign table</glossterm> <glossterm>Foreign table (relation)</glossterm>
<glossdef> <glossdef>
<para> <para>
A <glossterm linkend="glossary-relation">relation</glossterm> which appears to have A <glossterm linkend="glossary-relation">relation</glossterm> which appears to have
...@@ -631,12 +652,20 @@ ...@@ -631,12 +652,20 @@
</glossentry> </glossentry>
<glossentry id="glossary-function"> <glossentry id="glossary-function">
<glossterm>Function</glossterm> <glossterm>Function (routine)</glossterm>
<glossdef> <glossdef>
<para> <para>
Any defined transformation of data. Many functions are already defined A type of routine that receives zero or more arguments, returns zero or more
within <productname>PostgreSQL</productname> itself, but user-defined output values, and is constrained to run within one transaction.
ones can also be added. Functions are invoked as part of a query, for example via
<command>SELECT</command>.
Certain functions can return
<glossterm linkend="glossary-result-set">sets</glossterm>; those are
called <firstterm>set-returning functions</firstterm>.
</para>
<para>
Functions can also be used for
<glossterm linkend="glossary-trigger">triggers</glossterm> to invoke.
</para> </para>
<para> <para>
For more information, see For more information, see
...@@ -689,13 +718,12 @@ ...@@ -689,13 +718,12 @@
</glossentry> </glossentry>
<glossentry id="glossary-index"> <glossentry id="glossary-index">
<glossterm>Index</glossterm> <glossterm>Index (relation)</glossterm>
<glossdef> <glossdef>
<para> <para>
A <glossterm linkend="glossary-relation">relation</glossterm> that contains A <glossterm linkend="glossary-relation">relation</glossterm> that contains
data derived from a <glossterm linkend="glossary-table">table</glossterm> data derived from a <glossterm linkend="glossary-table">table</glossterm>
(or <glossterm linkend="glossary-relation">relation</glossterm> types or <glossterm linkend="glossary-materialized-view">materialized view</glossterm>.
such as a <glossterm linkend="glossary-materialized-view">materialized view</glossterm>).
Its internal structure supports fast retrieval of and access to the original Its internal structure supports fast retrieval of and access to the original
data. data.
</para> </para>
...@@ -724,14 +752,12 @@ ...@@ -724,14 +752,12 @@
<glossterm>Instance</glossterm> <glossterm>Instance</glossterm>
<glossdef> <glossdef>
<para> <para>
A set of databases and accompanying global SQL objects that are stored in A group of backend and auxiliary processes that communicate using
the same <glossterm linkend="glossary-data-directory">data directory</glossterm> a common shared memory area. One
in a single <glossterm linkend="glossary-server">server</glossterm>.
If running, one
<glossterm linkend="glossary-postmaster">postmaster process</glossterm> <glossterm linkend="glossary-postmaster">postmaster process</glossterm>
manages a group of backend and auxiliary processes that communicate manages the instance; one instance manages exactly one
using a common <glossterm linkend="glossary-shared-memory">shared memory</glossterm> <glossterm linkend="glossary-db-cluster">database cluster</glossterm>
area. Many instances can run on the same with all its databases. Many instances can run on the same
<glossterm linkend="glossary-server">server</glossterm> <glossterm linkend="glossary-server">server</glossterm>
as long as their <acronym>TCP</acronym> ports do not conflict. as long as their <acronym>TCP</acronym> ports do not conflict.
</para> </para>
...@@ -739,14 +765,10 @@ ...@@ -739,14 +765,10 @@
The instance handles all key features of a <acronym>DBMS</acronym>: The instance handles all key features of a <acronym>DBMS</acronym>:
read and write access to files and shared memory, read and write access to files and shared memory,
assurance of the <acronym>ACID</acronym> properties, assurance of the <acronym>ACID</acronym> properties,
<glossterm linkend="glossary-connection">connections</glossterm> to client processes, <glossterm linkend="glossary-connection">connections</glossterm> to
<glossterm linkend="glossary-client">client processes</glossterm>,
privilege verification, crash recovery, replication, etc. privilege verification, crash recovery, replication, etc.
</para> </para>
<para>
In <productname>PostgreSQL</productname>, the term
<firstterm>cluster</firstterm> is also sometimes used to refer to an instance.
(Don't confuse this term with the SQL command <command>CLUSTER</command>.)
</para>
</glossdef> </glossdef>
</glossentry> </glossentry>
...@@ -769,8 +791,10 @@ ...@@ -769,8 +791,10 @@
<glossterm>Join</glossterm> <glossterm>Join</glossterm>
<glossdef> <glossdef>
<para> <para>
An <acronym>SQL</acronym> keyword used in <command>SELECT</command> statements for An operation and <acronym>SQL</acronym> keyword used in
combining data from multiple <glossterm linkend="glossary-relation">relations</glossterm>. <glossterm linkend="glossary-query">queries</glossterm>
for combining data from multiple
<glossterm linkend="glossary-relation">relations</glossterm>.
</para> </para>
</glossdef> </glossdef>
</glossentry> </glossentry>
...@@ -781,10 +805,10 @@ ...@@ -781,10 +805,10 @@
<para> <para>
A means of identifying a <glossterm linkend="glossary-tuple">row</glossterm> within a A means of identifying a <glossterm linkend="glossary-tuple">row</glossterm> within a
<glossterm linkend="glossary-table">table</glossterm> or <glossterm linkend="glossary-table">table</glossterm> or
<glossterm linkend="glossary-relation">relation</glossterm> by other <glossterm linkend="glossary-relation">relation</glossterm> by
values contained within one or more values contained within one or more
<glossterm linkend="glossary-attribute">attributes</glossterm> <glossterm linkend="glossary-attribute">attributes</glossterm>
in that table. in that relation.
</para> </para>
</glossdef> </glossdef>
</glossentry> </glossentry>
...@@ -813,15 +837,6 @@ ...@@ -813,15 +837,6 @@
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry id="glossary-log-record">
<glossterm>Log record</glossterm>
<glossdef>
<para>
Archaic term for a <glossterm linkend="glossary-wal-record">WAL record</glossterm>.
</para>
</glossdef>
</glossentry>
<glossentry id="glossary-logged"> <glossentry id="glossary-logged">
<glossterm>Logged</glossterm> <glossterm>Logged</glossterm>
<glossdef> <glossdef>
...@@ -855,6 +870,15 @@ ...@@ -855,6 +870,15 @@
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry id="glossary-log-record">
<glossterm>Log record</glossterm>
<glossdef>
<para>
Archaic term for a <glossterm linkend="glossary-wal-record">WAL record</glossterm>.
</para>
</glossdef>
</glossentry>
<glossentry> <glossentry>
<glossterm>Master (server)</glossterm> <glossterm>Master (server)</glossterm>
<glosssee otherterm="glossary-primary-server" /> <glosssee otherterm="glossary-primary-server" />
...@@ -883,12 +907,13 @@ ...@@ -883,12 +907,13 @@
</glossentry> </glossentry>
<glossentry id="glossary-materialized-view"> <glossentry id="glossary-materialized-view">
<glossterm>Materialized view</glossterm> <glossterm>Materialized view (relation)</glossterm>
<glossdef> <glossdef>
<para> <para>
A <glossterm linkend="glossary-relation">relation</glossterm> that is A <glossterm linkend="glossary-relation">relation</glossterm> that is
defined in the same way that a <glossterm linkend="glossary-view">view</glossterm> defined by a <command>SELECT</command> statement
is, but stores data in the same way that a (just like a <glossterm linkend="glossary-view">view</glossterm>),
but stores data in the same way that a
<glossterm linkend="glossary-table">table</glossterm> does. It cannot be <glossterm linkend="glossary-table">table</glossterm> does. It cannot be
modified via <command>INSERT</command>, <command>UPDATE</command>, or modified via <command>INSERT</command>, <command>UPDATE</command>, or
<command>DELETE</command> operations. <command>DELETE</command> operations.
...@@ -949,6 +974,8 @@ ...@@ -949,6 +974,8 @@
<para> <para>
One of several disjoint (not overlapping) subsets of a larger set. One of several disjoint (not overlapping) subsets of a larger set.
</para> </para>
</glossdef>
<glossdef>
<para> <para>
In reference to a In reference to a
<glossterm linkend="glossary-partitioned-table">partitioned table</glossterm>: <glossterm linkend="glossary-partitioned-table">partitioned table</glossterm>:
...@@ -961,16 +988,18 @@ ...@@ -961,16 +988,18 @@
</glossdef> </glossdef>
<glossdef> <glossdef>
<para> <para>
In reference to a <glossterm linkend="glossary-window-function">window function</glossterm>: In reference to a <glossterm linkend="glossary-window-function">window function</glossterm>
in a <glossterm linkend="glossary-query">query</glossterm>,
a partition is a user-defined criterion that identifies which neighboring a partition is a user-defined criterion that identifies which neighboring
<glossterm linkend="glossary-tuple">rows</glossterm> can be considered by the <glossterm linkend="glossary-tuple">rows</glossterm>
function. of the <glossterm linkend="glossary-result-set">query's result set</glossterm>
can be considered by the function.
</para> </para>
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry id="glossary-partitioned-table"> <glossentry id="glossary-partitioned-table">
<glossterm>Partitioned table</glossterm> <glossterm>Partitioned table (relation)</glossterm>
<glossdef> <glossdef>
<para> <para>
A <glossterm linkend="glossary-relation">relation</glossterm> that is A <glossterm linkend="glossary-relation">relation</glossterm> that is
...@@ -997,20 +1026,6 @@ ...@@ -997,20 +1026,6 @@
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry id="glossary-primary-server">
<glossterm>Primary (server)</glossterm>
<glossdef>
<para>
When two or more <glossterm linkend="glossary-database">databases</glossterm>
are linked via <glossterm linkend="glossary-replication">replication</glossterm>,
the <glossterm linkend="glossary-server">server</glossterm>
that is considered the authoritative source of information is called
the <firstterm>primary</firstterm>,
also known as a <firstterm>master</firstterm>.
</para>
</glossdef>
</glossentry>
<glossentry id="glossary-primary-key"> <glossentry id="glossary-primary-key">
<glossterm>Primary key</glossterm> <glossterm>Primary key</glossterm>
<glossdef> <glossdef>
...@@ -1031,19 +1046,29 @@ ...@@ -1031,19 +1046,29 @@
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry id="glossary-primary-server">
<glossterm>Primary (server)</glossterm>
<glossdef>
<para>
When two or more <glossterm linkend="glossary-database">databases</glossterm>
are linked via <glossterm linkend="glossary-replication">replication</glossterm>,
the <glossterm linkend="glossary-server">server</glossterm>
that is considered the authoritative source of information is called
the <firstterm>primary</firstterm>,
also known as a <firstterm>master</firstterm>.
</para>
</glossdef>
</glossentry>
<glossentry id="glossary-procedure"> <glossentry id="glossary-procedure">
<glossterm>Procedure</glossterm> <glossterm>Procedure (routine)</glossterm>
<glossdef> <glossdef>
<para> <para>
A defined set of instructions for manipulating data within a A type of routine.
<glossterm linkend="glossary-database">database</glossterm>. Their distinctive qualities are that they do not return values,
A <glossterm linkend="glossary-procedure">procedure</glossterm> can and that they are allowed to make transactional statements such
be written in a variety of programming languages. They are
similar to <glossterm linkend="glossary-function">functions</glossterm>,
but are different in that they must be invoked via the <command>CALL</command>
command rather than the <command>SELECT</command> or <command>PERFORM</command>
commands, and they are allowed to make transactional statements such
as <command>COMMIT</command> and <command>ROLLBACK</command>. as <command>COMMIT</command> and <command>ROLLBACK</command>.
They are invoked via the <command>CALL</command> command.
</para> </para>
<para> <para>
For more information, see For more information, see
...@@ -1115,6 +1140,11 @@ ...@@ -1115,6 +1140,11 @@
<glossterm linkend="glossary-index">indexes</glossterm> are all relations. <glossterm linkend="glossary-index">indexes</glossterm> are all relations.
</para> </para>
<para> <para>
More generically, a relation is a set of tuples; for example,
the result of a query is also a relation.
</para>
<para>
In <productname>PostgreSQL</productname>,
<firstterm>Class</firstterm> is an archaic synonym for <firstterm>Class</firstterm> is an archaic synonym for
<firstterm>relation</firstterm>. <firstterm>relation</firstterm>.
</para> </para>
...@@ -1155,16 +1185,23 @@ ...@@ -1155,16 +1185,23 @@
<glossterm>Result set</glossterm> <glossterm>Result set</glossterm>
<glossdef> <glossdef>
<para> <para>
A data structure transmitted from a A <glossterm linkend="glossary-relation">relation</glossterm> transmitted
<glossterm linkend="glossary-backend">backend process</glossterm> to from a <glossterm linkend="glossary-backend">backend process</glossterm>
a <glossterm linkend="glossary-client">client</glossterm> upon the to a <glossterm linkend="glossary-client">client</glossterm> upon the
completion of an <acronym>SQL</acronym> completion of an <acronym>SQL</acronym> command, usually a
command, usually a <command>SELECT</command> but it can be an <command>SELECT</command> but it can be an
<command>INSERT</command>, <command>UPDATE</command>, or <command>INSERT</command>, <command>UPDATE</command>, or
<command>DELETE</command> command if the <literal>RETURNING</literal> <command>DELETE</command> command if the <literal>RETURNING</literal>
clause is specified. The data structure consists of zero or more clause is specified.
<glossterm linkend="glossary-tuple">rows</glossterm> with the same ordered set of </para>
<glossterm linkend="glossary-attribute">attributes</glossterm>. <para>
The fact that a result set is a relation means that a query can be used
in the definition of another query, becoming a
<firstterm>subquery</firstterm>.
</para>
</glossdef>
<glossdef>
<para>
</para> </para>
</glossdef> </glossdef>
</glossentry> </glossentry>
...@@ -1216,6 +1253,27 @@ ...@@ -1216,6 +1253,27 @@
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry id="glossary-routine">
<glossterm>Routine</glossterm>
<glossdef>
<para>
A defined set of instructions stored in the database system
that can be invoked for execution.
A routine can be written in a variety of programming
languages. Routines can be
<glossterm linkend="glossary-function">functions</glossterm>
(including set-returning functions and
<glossterm linkend="glossary-trigger">trigger functions</glossterm>),
<glossterm linkend="glossary-aggregate">aggregate functions</glossterm>,
and <glossterm linkend="glossary-procedure">procedures</glossterm>.
</para>
<para>
Many routines are already defined within <productname>PostgreSQL</productname>
itself, but user-defined ones can also be added.
</para>
</glossdef>
</glossentry>
<glossentry> <glossentry>
<glossterm>Row</glossterm> <glossterm>Row</glossterm>
<glosssee otherterm="glossary-tuple" /> <glosssee otherterm="glossary-tuple" />
...@@ -1248,16 +1306,7 @@ ...@@ -1248,16 +1306,7 @@
Each SQL object must reside in exactly one schema. Each SQL object must reside in exactly one schema.
</para> </para>
<para> <para>
The names of SQL objects of the same type in the same schema are enforced All system-defined SQL objects reside in schema <literal>pg_catalog</literal>.
to be unique.
There is no restriction on reusing a name in multiple schemas.
</para>
<para>
All system-defined SQL objects reside in schema <literal>pg_catalog</literal>,
and commonly many user-defined SQL objects reside in the default schema
<literal>public</literal>,
but it is common and recommended that other schemas are created to hold
application-specific SQL objects.
</para> </para>
</glossdef> </glossdef>
<glossdef> <glossdef>
...@@ -1299,6 +1348,19 @@ ...@@ -1299,6 +1348,19 @@
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry id="glossary-sequence">
<glossterm>Sequence (relation)</glossterm>
<glossdef>
<para>
A type of relation that is used to generate values.
Typically the generated values are sequential non-repeating numbers.
They are commonly used to generate surrogate
<glossterm linkend="glossary-primary-key">primary key</glossterm>
values.
</para>
</glossdef>
</glossentry>
<!-- XXX should define all other isolation levels (and improve this definition) <!-- XXX should define all other isolation levels (and improve this definition)
<glossentry id="glossary-serializable"> <glossentry id="glossary-serializable">
<glossterm>Serializable (isolation level)</glossterm> <glossterm>Serializable (isolation level)</glossterm>
...@@ -1339,19 +1401,6 @@ ...@@ -1339,19 +1401,6 @@
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry id="glossary-sequence">
<glossterm>Sequence</glossterm>
<glossdef>
<para>
A type of relation that is used to generate values.
Typically the generated values are sequential non-repeating numbers.
They are commonly used to generate surrogate
<glossterm linkend="glossary-primary-key">primary key</glossterm>
values.
</para>
</glossdef>
</glossentry>
<glossentry id="glossary-shared-memory"> <glossentry id="glossary-shared-memory">
<glossterm>Shared memory</glossterm> <glossterm>Shared memory</glossterm>
<glossdef> <glossdef>
...@@ -1378,32 +1427,42 @@ ...@@ -1378,32 +1427,42 @@
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry>
<glossterm>Standby (server)</glossterm>
<glosssee otherterm="glossary-replica" />
</glossentry>
<glossentry id="glossary-sql-object"> <glossentry id="glossary-sql-object">
<glossterm>SQL Object</glossterm> <glossterm>SQL object</glossterm>
<glossdef> <glossdef>
<para> <para>
Any object that can be created with a <command>CREATE</command> Any object that can be created with a <command>CREATE</command>
command. Most objects are specific to one database, and are commonly command. Most objects are specific to one database, and are commonly
known as <firstterm>local objects</firstterm>. known as <firstterm>local objects</firstterm>.
<glossterm linkend="glossary-role">Roles</glossterm>,
<glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
replication origins, subscriptions for logical replication, and
databases themselves are not local SQL objects since they exist
entirely outside of any specific database;
they are called <firstterm>global objects</firstterm>.
</para> </para>
<para> <para>
Most local objects belong to a specific Most local objects belong to a specific
<glossterm linkend="glossary-schema">schema</glossterm> in their containing database. <glossterm linkend="glossary-schema">schema</glossterm> in their
containing database, such as
<glossterm linkend="glossary-relation">relations</glossterm> (all types),
<glossterm linkend="glossary-function">routines</glossterm> (all types),
data types, etc.
The names of such objects of the same type in the same schema
are enforced to be unique.
</para>
<para>
There also exist local objects that do not belong to schemas; some examples are There also exist local objects that do not belong to schemas; some examples are
<glossterm linkend="glossary-extension">extensions</glossterm>, <glossterm linkend="glossary-extension">extensions</glossterm>,
<glossterm linkend="glossary-cast">data type casts</glossterm>, and <glossterm linkend="glossary-cast">data type casts</glossterm>, and
<glossterm linkend="glossary-foreign-data-wrapper">foreign data wrappers</glossterm>. <glossterm linkend="glossary-foreign-data-wrapper">foreign data wrappers</glossterm>.
The names of such objects of the same type are enforced to be unique
within the database.
</para>
<para>
Other object types, such as
<glossterm linkend="glossary-role">roles</glossterm>,
<glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
replication origins, subscriptions for logical replication, and
databases themselves are not local SQL objects since they exist
entirely outside of any specific database;
they are called <firstterm>global objects</firstterm>.
The names of such objects are enforced to be unique within the whole
database cluster.
</para> </para>
<para> <para>
For more information, see For more information, see
...@@ -1421,6 +1480,11 @@ ...@@ -1421,6 +1480,11 @@
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry>
<glossterm>Standby (server)</glossterm>
<glosssee otherterm="glossary-replica" />
</glossentry>
<glossentry id="glossary-stats-collector"> <glossentry id="glossary-stats-collector">
<glossterm>Stats collector</glossterm> <glossterm>Stats collector</glossterm>
<glossdef> <glossdef>
...@@ -1489,8 +1553,8 @@ ...@@ -1489,8 +1553,8 @@
which require storage beyond their definition in the which require storage beyond their definition in the
<glossterm linkend="glossary-system-catalog">system catalog</glossterm> <glossterm linkend="glossary-system-catalog">system catalog</glossterm>
must belong to a single tablespace. must belong to a single tablespace.
Initially, an instance contains a single usable tablespace which is Initially, a database cluster contains a single usable tablespace which is
used as the default one for all SQL objects, called <literal>pg_default</literal>. used as the default for all SQL objects, called <literal>pg_default</literal>.
</para> </para>
<para> <para>
For more information, see For more information, see
...@@ -1577,6 +1641,18 @@ ...@@ -1577,6 +1641,18 @@
</glossdef> </glossdef>
</glossentry> </glossentry>
<glossentry id="glossary-tps">
<glossterm>Transactions per second (TPS)</glossterm>
<glossdef>
<para>
Average number of transactions that are executed per second,
totalled across all sessions active for a measured run.
This is used as a measure of the performance characteristics of
an instance.
</para>
</glossdef>
</glossentry>
<glossentry id="glossary-trigger"> <glossentry id="glossary-trigger">
<glossterm>Trigger</glossterm> <glossterm>Trigger</glossterm>
<glossdef> <glossdef>
...@@ -1605,6 +1681,7 @@ ...@@ -1605,6 +1681,7 @@
A collection of <glossterm linkend="glossary-attribute">attributes</glossterm> A collection of <glossterm linkend="glossary-attribute">attributes</glossterm>
in a fixed order. in a fixed order.
That order may be defined by the <glossterm linkend="glossary-table">table</glossterm> That order may be defined by the <glossterm linkend="glossary-table">table</glossterm>
(or other <glossterm linkend="glossary-relation">relation</glossterm>)
where the tuple is contained, in which case the tuple is often called a where the tuple is contained, in which case the tuple is often called a
<firstterm>row</firstterm>. It may also be defined by the structure of a <firstterm>row</firstterm>. It may also be defined by the structure of a
result set, in which case it is sometimes called a <firstterm>record</firstterm>. result set, in which case it is sometimes called a <firstterm>record</firstterm>.
...@@ -1833,13 +1910,17 @@ ...@@ -1833,13 +1910,17 @@
</glossentry> </glossentry>
<glossentry id="glossary-window-function"> <glossentry id="glossary-window-function">
<glossterm>Window function</glossterm> <glossterm>Window function (routine)</glossterm>
<glossdef> <glossdef>
<para> <para>
A type of <glossterm linkend="glossary-function">function</glossterm> whose A type of <glossterm linkend="glossary-function">function</glossterm>
result is based on values found in used in a <glossterm linkend="glossary-query">query</glossterm>
<glossterm linkend="glossary-tuple">rows</glossterm> of the same that applies to a <glossterm linkend="glossary-partition">partition</glossterm>
<glossterm linkend="glossary-partition">partition</glossterm>. of the query's <glossterm linkend="glossary-result-set">result set</glossterm>;
the function's result is based on values found in
<glossterm linkend="glossary-tuple">rows</glossterm> of the same partition or frame.
</para>
<para>
All <glossterm linkend="glossary-aggregate">aggregate functions</glossterm> All <glossterm linkend="glossary-aggregate">aggregate functions</glossterm>
can be used as window functions, but window functions can also be can be used as window functions, but window functions can also be
used to, for example, give ranks to each of the rows in the partition. used to, for example, give ranks to each of the rows in the partition.
...@@ -1857,8 +1938,8 @@ ...@@ -1857,8 +1938,8 @@
<glossdef> <glossdef>
<para> <para>
The journal that keeps track of the changes in the The journal that keeps track of the changes in the
<glossterm linkend="glossary-instance">instance</glossterm> as user- and <glossterm linkend="glossary-db-cluster">database cluster</glossterm>
system-invoked operations take place. as user- and system-invoked operations take place.
It comprises many individual It comprises many individual
<glossterm linkend="glossary-wal-record">WAL records</glossterm> written <glossterm linkend="glossary-wal-record">WAL records</glossterm> written
sequentially to <glossterm linkend="glossary-wal-file">WAL files</glossterm>. sequentially to <glossterm linkend="glossary-wal-file">WAL files</glossterm>.
......
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