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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: Jürgen Purtz <juergen@purtz.de> Reviewed-by: Justin Pryzby <pryzby@telsasoft.com> Reviewed-by: Erik Rijkers <er@xs4all.nl> Discussion: https://postgr.es/m/c1e06008-2132-30f4-9b38-877e8683d418@purtz.de
This commit is contained in:
Alvaro Herrera
parent
be14f884d5
commit
816cbb59e3
@ -23,7 +23,7 @@
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</glossentry>
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<glossentry id="glossary-aggregate">
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<glossterm>Aggregate function</glossterm>
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<glossterm>Aggregate function (routine)</glossterm>
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<glossdef>
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<para>
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A <glossterm linkend="glossary-function">function</glossterm> that
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@ -39,6 +39,11 @@
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</glossdef>
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</glossentry>
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<glossentry>
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<glossterm>Analytic function</glossterm>
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<glosssee otherterm="glossary-window-function" />
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</glossentry>
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<glossentry id="glossary-analyze">
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<glossterm>Analyze (operation)</glossterm>
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<glossdef>
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@ -54,14 +59,13 @@
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(Don't confuse this term with the <literal>ANALYZE</literal> option
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to the <xref linkend="sql-explain"/> command.)
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</para>
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<para>
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For more information, see
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<xref linkend="sql-analyze"/>.
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</para>
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</glossdef>
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</glossentry>
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<glossentry>
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<glossterm>Analytic function</glossterm>
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<glosssee otherterm="glossary-window-function" />
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</glossentry>
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<glossentry id="glossary-atomic">
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<glossterm>Atomic</glossterm>
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<glossdef>
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@ -98,8 +102,7 @@
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<glossdef>
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<para>
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An element with a certain name and data type found within a
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<glossterm linkend="glossary-tuple">tuple</glossterm> or
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<glossterm linkend="glossary-table">table</glossterm>.
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<glossterm linkend="glossary-tuple">tuple</glossterm>.
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</para>
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</glossdef>
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</glossentry>
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@ -389,36 +392,12 @@
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<glosssee otherterm="glossary-data-directory" />
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</glossentry>
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<glossentry id="glossary-data-directory">
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<glossterm>Data directory</glossterm>
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<glossdef>
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<para>
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The base directory on the filesystem of a
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<glossterm linkend="glossary-server">server</glossterm> that contains all
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data files and subdirectories associated with an
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<glossterm linkend="glossary-instance">instance</glossterm> (with the
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exception of <glossterm linkend="glossary-tablespace">tablespaces</glossterm>).
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The environment variable <literal>PGDATA</literal> is commonly used to
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refer to the
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<glossterm linkend="glossary-data-directory">data directory</glossterm>.
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</para>
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<para>
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An <glossterm linkend="glossary-instance">instance</glossterm>'s storage
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space comprises the data directory plus any additional tablespaces.
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</para>
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<para>
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For more information, see
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<xref linkend="storage-file-layout"/>.
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</para>
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</glossdef>
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</glossentry>
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<glossentry id="glossary-database">
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<glossterm>Database</glossterm>
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<glossdef>
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<para>
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A named collection of
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<glossterm linkend="glossary-sql-object">SQL objects</glossterm>.
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<glossterm linkend="glossary-sql-object">local SQL objects</glossterm>.
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</para>
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<para>
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For more information, see
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@ -427,11 +406,53 @@
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</glossdef>
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</glossentry>
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<glossentry id="glossary-db-cluster">
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<glossterm>Database cluster</glossterm>
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<glossdef>
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<para>
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A collection of databases and global SQL objects,
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and their common static and dynamic metadata.
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Sometimes referred to as a
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<firstterm>cluster</firstterm>.
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</para>
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<para>
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In <productname>PostgreSQL</productname>, the term
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<firstterm>cluster</firstterm> is also sometimes used to refer to an instance.
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(Don't confuse this term with the SQL command <command>CLUSTER</command>.)
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</para>
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</glossdef>
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</glossentry>
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<glossentry>
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<glossterm>Database server</glossterm>
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<glosssee otherterm="glossary-instance" />
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</glossentry>
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<glossentry id="glossary-data-directory">
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<glossterm>Data directory</glossterm>
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<glossdef>
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<para>
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The base directory on the filesystem of a
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<glossterm linkend="glossary-server">server</glossterm> that contains all
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data files and subdirectories associated with a
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<glossterm linkend="glossary-db-cluster">database cluster</glossterm>
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(with the exception of
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<glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
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and optionally <glossterm linkend="glossary-wal">WAL</glossterm>).
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The environment variable <literal>PGDATA</literal> is commonly used to
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refer to the data directory.
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</para>
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<para>
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A <glossterm linkend="glossary-db-cluster">cluster</glossterm>'s storage
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space comprises the data directory plus any additional tablespaces.
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</para>
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<para>
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For more information, see
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<xref linkend="storage-file-layout"/>.
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</para>
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</glossdef>
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</glossentry>
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<glossentry id="glossary-data-page">
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<glossterm>Data page</glossterm>
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<glossdef>
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@ -578,7 +599,7 @@
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</glossentry>
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<glossentry id="glossary-foreign-table">
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<glossterm>Foreign table</glossterm>
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<glossterm>Foreign table (relation)</glossterm>
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<glossdef>
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<para>
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A <glossterm linkend="glossary-relation">relation</glossterm> which appears to have
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@ -631,12 +652,20 @@
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</glossentry>
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<glossentry id="glossary-function">
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<glossterm>Function</glossterm>
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<glossterm>Function (routine)</glossterm>
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<glossdef>
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<para>
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Any defined transformation of data. Many functions are already defined
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within <productname>PostgreSQL</productname> itself, but user-defined
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ones can also be added.
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A type of routine that receives zero or more arguments, returns zero or more
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output values, and is constrained to run within one transaction.
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Functions are invoked as part of a query, for example via
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<command>SELECT</command>.
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Certain functions can return
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<glossterm linkend="glossary-result-set">sets</glossterm>; those are
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called <firstterm>set-returning functions</firstterm>.
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</para>
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<para>
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Functions can also be used for
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<glossterm linkend="glossary-trigger">triggers</glossterm> to invoke.
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</para>
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<para>
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For more information, see
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@ -689,13 +718,12 @@
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</glossentry>
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<glossentry id="glossary-index">
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<glossterm>Index</glossterm>
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<glossterm>Index (relation)</glossterm>
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<glossdef>
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<para>
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A <glossterm linkend="glossary-relation">relation</glossterm> that contains
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data derived from a <glossterm linkend="glossary-table">table</glossterm>
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(or <glossterm linkend="glossary-relation">relation</glossterm> types
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such as a <glossterm linkend="glossary-materialized-view">materialized view</glossterm>).
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or <glossterm linkend="glossary-materialized-view">materialized view</glossterm>.
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Its internal structure supports fast retrieval of and access to the original
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data.
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</para>
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@ -724,14 +752,12 @@
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<glossterm>Instance</glossterm>
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<glossdef>
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<para>
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A set of databases and accompanying global SQL objects that are stored in
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the same <glossterm linkend="glossary-data-directory">data directory</glossterm>
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in a single <glossterm linkend="glossary-server">server</glossterm>.
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If running, one
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A group of backend and auxiliary processes that communicate using
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a common shared memory area. One
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<glossterm linkend="glossary-postmaster">postmaster process</glossterm>
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manages a group of backend and auxiliary processes that communicate
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using a common <glossterm linkend="glossary-shared-memory">shared memory</glossterm>
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area. Many instances can run on the same
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manages the instance; one instance manages exactly one
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<glossterm linkend="glossary-db-cluster">database cluster</glossterm>
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with all its databases. Many instances can run on the same
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<glossterm linkend="glossary-server">server</glossterm>
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as long as their <acronym>TCP</acronym> ports do not conflict.
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</para>
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@ -739,14 +765,10 @@
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The instance handles all key features of a <acronym>DBMS</acronym>:
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read and write access to files and shared memory,
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assurance of the <acronym>ACID</acronym> properties,
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<glossterm linkend="glossary-connection">connections</glossterm> to client processes,
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<glossterm linkend="glossary-connection">connections</glossterm> to
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<glossterm linkend="glossary-client">client processes</glossterm>,
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privilege verification, crash recovery, replication, etc.
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</para>
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<para>
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In <productname>PostgreSQL</productname>, the term
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<firstterm>cluster</firstterm> is also sometimes used to refer to an instance.
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(Don't confuse this term with the SQL command <command>CLUSTER</command>.)
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</para>
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</glossdef>
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</glossentry>
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@ -769,8 +791,10 @@
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<glossterm>Join</glossterm>
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<glossdef>
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<para>
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An <acronym>SQL</acronym> keyword used in <command>SELECT</command> statements for
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combining data from multiple <glossterm linkend="glossary-relation">relations</glossterm>.
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An operation and <acronym>SQL</acronym> keyword used in
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<glossterm linkend="glossary-query">queries</glossterm>
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for combining data from multiple
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<glossterm linkend="glossary-relation">relations</glossterm>.
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</para>
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</glossdef>
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</glossentry>
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@ -781,10 +805,10 @@
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<para>
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A means of identifying a <glossterm linkend="glossary-tuple">row</glossterm> within a
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<glossterm linkend="glossary-table">table</glossterm> or
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<glossterm linkend="glossary-relation">relation</glossterm> by
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other <glossterm linkend="glossary-relation">relation</glossterm> by
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values contained within one or more
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<glossterm linkend="glossary-attribute">attributes</glossterm>
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in that table.
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in that relation.
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</para>
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</glossdef>
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</glossentry>
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@ -813,15 +837,6 @@
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</glossdef>
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</glossentry>
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<glossentry id="glossary-log-record">
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<glossterm>Log record</glossterm>
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<glossdef>
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<para>
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Archaic term for a <glossterm linkend="glossary-wal-record">WAL record</glossterm>.
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</para>
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</glossdef>
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</glossentry>
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<glossentry id="glossary-logged">
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<glossterm>Logged</glossterm>
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<glossdef>
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@ -855,6 +870,15 @@
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</glossdef>
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</glossentry>
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<glossentry id="glossary-log-record">
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<glossterm>Log record</glossterm>
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<glossdef>
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<para>
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Archaic term for a <glossterm linkend="glossary-wal-record">WAL record</glossterm>.
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</para>
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</glossdef>
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</glossentry>
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<glossentry>
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<glossterm>Master (server)</glossterm>
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<glosssee otherterm="glossary-primary-server" />
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@ -883,12 +907,13 @@
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</glossentry>
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<glossentry id="glossary-materialized-view">
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<glossterm>Materialized view</glossterm>
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<glossterm>Materialized view (relation)</glossterm>
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<glossdef>
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<para>
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A <glossterm linkend="glossary-relation">relation</glossterm> that is
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defined in the same way that a <glossterm linkend="glossary-view">view</glossterm>
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is, but stores data in the same way that a
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defined by a <command>SELECT</command> statement
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(just like a <glossterm linkend="glossary-view">view</glossterm>),
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but stores data in the same way that a
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<glossterm linkend="glossary-table">table</glossterm> does. It cannot be
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modified via <command>INSERT</command>, <command>UPDATE</command>, or
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<command>DELETE</command> operations.
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@ -949,6 +974,8 @@
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<para>
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One of several disjoint (not overlapping) subsets of a larger set.
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</para>
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</glossdef>
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<glossdef>
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<para>
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In reference to a
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<glossterm linkend="glossary-partitioned-table">partitioned table</glossterm>:
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@ -961,16 +988,18 @@
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</glossdef>
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<glossdef>
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<para>
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In reference to a <glossterm linkend="glossary-window-function">window function</glossterm>:
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In reference to a <glossterm linkend="glossary-window-function">window function</glossterm>
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in a <glossterm linkend="glossary-query">query</glossterm>,
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a partition is a user-defined criterion that identifies which neighboring
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<glossterm linkend="glossary-tuple">rows</glossterm> can be considered by the
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function.
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<glossterm linkend="glossary-tuple">rows</glossterm>
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of the <glossterm linkend="glossary-result-set">query's result set</glossterm>
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can be considered by the function.
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</para>
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</glossdef>
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</glossentry>
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<glossentry id="glossary-partitioned-table">
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<glossterm>Partitioned table</glossterm>
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<glossterm>Partitioned table (relation)</glossterm>
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<glossdef>
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<para>
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A <glossterm linkend="glossary-relation">relation</glossterm> that is
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@ -997,20 +1026,6 @@
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</glossdef>
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</glossentry>
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<glossentry id="glossary-primary-server">
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<glossterm>Primary (server)</glossterm>
|
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<glossdef>
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<para>
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When two or more <glossterm linkend="glossary-database">databases</glossterm>
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are linked via <glossterm linkend="glossary-replication">replication</glossterm>,
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the <glossterm linkend="glossary-server">server</glossterm>
|
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that is considered the authoritative source of information is called
|
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the <firstterm>primary</firstterm>,
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also known as a <firstterm>master</firstterm>.
|
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</para>
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</glossdef>
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</glossentry>
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<glossentry id="glossary-primary-key">
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<glossterm>Primary key</glossterm>
|
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<glossdef>
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@ -1031,19 +1046,29 @@
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</glossdef>
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</glossentry>
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<glossentry id="glossary-procedure">
|
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<glossterm>Procedure</glossterm>
|
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<glossentry id="glossary-primary-server">
|
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<glossterm>Primary (server)</glossterm>
|
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<glossdef>
|
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<para>
|
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A defined set of instructions for manipulating data within a
|
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<glossterm linkend="glossary-database">database</glossterm>.
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A <glossterm linkend="glossary-procedure">procedure</glossterm> can
|
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be written in a variety of programming languages. They are
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similar to <glossterm linkend="glossary-function">functions</glossterm>,
|
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but are different in that they must be invoked via the <command>CALL</command>
|
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command rather than the <command>SELECT</command> or <command>PERFORM</command>
|
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commands, and they are allowed to make transactional statements such
|
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When two or more <glossterm linkend="glossary-database">databases</glossterm>
|
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are linked via <glossterm linkend="glossary-replication">replication</glossterm>,
|
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the <glossterm linkend="glossary-server">server</glossterm>
|
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that is considered the authoritative source of information is called
|
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the <firstterm>primary</firstterm>,
|
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also known as a <firstterm>master</firstterm>.
|
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</para>
|
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</glossdef>
|
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</glossentry>
|
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|
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<glossentry id="glossary-procedure">
|
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<glossterm>Procedure (routine)</glossterm>
|
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<glossdef>
|
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<para>
|
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A type of routine.
|
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Their distinctive qualities are that they do not return values,
|
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and that they are allowed to make transactional statements such
|
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as <command>COMMIT</command> and <command>ROLLBACK</command>.
|
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They are invoked via the <command>CALL</command> command.
|
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</para>
|
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<para>
|
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For more information, see
|
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@ -1115,6 +1140,11 @@
|
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<glossterm linkend="glossary-index">indexes</glossterm> are all relations.
|
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</para>
|
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<para>
|
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More generically, a relation is a set of tuples; for example,
|
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the result of a query is also a relation.
|
||||
</para>
|
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<para>
|
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In <productname>PostgreSQL</productname>,
|
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<firstterm>Class</firstterm> is an archaic synonym for
|
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<firstterm>relation</firstterm>.
|
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</para>
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@ -1155,16 +1185,23 @@
|
||||
<glossterm>Result set</glossterm>
|
||||
<glossdef>
|
||||
<para>
|
||||
A data structure transmitted from a
|
||||
<glossterm linkend="glossary-backend">backend process</glossterm> to
|
||||
a <glossterm linkend="glossary-client">client</glossterm> upon the
|
||||
completion of an <acronym>SQL</acronym>
|
||||
command, usually a <command>SELECT</command> but it can be an
|
||||
A <glossterm linkend="glossary-relation">relation</glossterm> transmitted
|
||||
from a <glossterm linkend="glossary-backend">backend process</glossterm>
|
||||
to a <glossterm linkend="glossary-client">client</glossterm> upon the
|
||||
completion of an <acronym>SQL</acronym> command, usually a
|
||||
<command>SELECT</command> but it can be an
|
||||
<command>INSERT</command>, <command>UPDATE</command>, or
|
||||
<command>DELETE</command> command if the <literal>RETURNING</literal>
|
||||
clause is specified. The data structure consists of zero or more
|
||||
<glossterm linkend="glossary-tuple">rows</glossterm> with the same ordered set of
|
||||
<glossterm linkend="glossary-attribute">attributes</glossterm>.
|
||||
clause is specified.
|
||||
</para>
|
||||
<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>
|
||||
</glossdef>
|
||||
</glossentry>
|
||||
@ -1216,6 +1253,27 @@
|
||||
</glossdef>
|
||||
</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>
|
||||
<glossterm>Row</glossterm>
|
||||
<glosssee otherterm="glossary-tuple" />
|
||||
@ -1248,16 +1306,7 @@
|
||||
Each SQL object must reside in exactly one schema.
|
||||
</para>
|
||||
<para>
|
||||
The names of SQL objects of the same type in the same schema are enforced
|
||||
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.
|
||||
All system-defined SQL objects reside in schema <literal>pg_catalog</literal>.
|
||||
</para>
|
||||
</glossdef>
|
||||
<glossdef>
|
||||
@ -1299,6 +1348,19 @@
|
||||
</glossdef>
|
||||
</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)
|
||||
<glossentry id="glossary-serializable">
|
||||
<glossterm>Serializable (isolation level)</glossterm>
|
||||
@ -1339,19 +1401,6 @@
|
||||
</glossdef>
|
||||
</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">
|
||||
<glossterm>Shared memory</glossterm>
|
||||
<glossdef>
|
||||
@ -1378,33 +1427,43 @@
|
||||
</glossdef>
|
||||
</glossentry>
|
||||
|
||||
<glossentry>
|
||||
<glossterm>Standby (server)</glossterm>
|
||||
<glosssee otherterm="glossary-replica" />
|
||||
</glossentry>
|
||||
|
||||
<glossentry id="glossary-sql-object">
|
||||
<glossterm>SQL Object</glossterm>
|
||||
<glossterm>SQL object</glossterm>
|
||||
<glossdef>
|
||||
<para>
|
||||
Any object that can be created with a <command>CREATE</command>
|
||||
command. Most objects are specific to one database, and are commonly
|
||||
known as <firstterm>local objects</firstterm>.
|
||||
<glossterm linkend="glossary-role">Roles</glossterm>,
|
||||
</para>
|
||||
<para>
|
||||
Most local objects belong to a specific
|
||||
<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
|
||||
<glossterm linkend="glossary-extension">extensions</glossterm>,
|
||||
<glossterm linkend="glossary-cast">data type casts</glossterm>, and
|
||||
<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>
|
||||
Most local objects belong to a specific
|
||||
<glossterm linkend="glossary-schema">schema</glossterm> in their containing database.
|
||||
There also exist local objects that do not belong to schemas; some examples are
|
||||
<glossterm linkend="glossary-extension">extensions</glossterm>,
|
||||
<glossterm linkend="glossary-cast">data type casts</glossterm>, and
|
||||
<glossterm linkend="glossary-foreign-data-wrapper">foreign data wrappers</glossterm>.
|
||||
</para>
|
||||
<para>
|
||||
For more information, see
|
||||
<xref linkend="manage-ag-overview"/>.
|
||||
@ -1421,6 +1480,11 @@
|
||||
</glossdef>
|
||||
</glossentry>
|
||||
|
||||
<glossentry>
|
||||
<glossterm>Standby (server)</glossterm>
|
||||
<glosssee otherterm="glossary-replica" />
|
||||
</glossentry>
|
||||
|
||||
<glossentry id="glossary-stats-collector">
|
||||
<glossterm>Stats collector</glossterm>
|
||||
<glossdef>
|
||||
@ -1489,8 +1553,8 @@
|
||||
which require storage beyond their definition in the
|
||||
<glossterm linkend="glossary-system-catalog">system catalog</glossterm>
|
||||
must belong to a single tablespace.
|
||||
Initially, an instance contains a single usable tablespace which is
|
||||
used as the default one for all SQL objects, called <literal>pg_default</literal>.
|
||||
Initially, a database cluster contains a single usable tablespace which is
|
||||
used as the default for all SQL objects, called <literal>pg_default</literal>.
|
||||
</para>
|
||||
<para>
|
||||
For more information, see
|
||||
@ -1577,6 +1641,18 @@
|
||||
</glossdef>
|
||||
</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">
|
||||
<glossterm>Trigger</glossterm>
|
||||
<glossdef>
|
||||
@ -1605,6 +1681,7 @@
|
||||
A collection of <glossterm linkend="glossary-attribute">attributes</glossterm>
|
||||
in a fixed order.
|
||||
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
|
||||
<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>.
|
||||
@ -1818,28 +1895,32 @@
|
||||
</glossentry>
|
||||
|
||||
<glossentry id="glossary-wal-writer">
|
||||
<glossterm>WAL writer (process)</glossterm>
|
||||
<glossdef>
|
||||
<para>
|
||||
A process that writes <glossterm linkend="glossary-wal-record">WAL records</glossterm>
|
||||
from <glossterm linkend="glossary-shared-memory">shared memory</glossterm> to
|
||||
<glossterm linkend="glossary-wal-file">WAL files</glossterm>.
|
||||
</para>
|
||||
<para>
|
||||
For more information, see
|
||||
<xref linkend="runtime-config-wal"/>.
|
||||
</para>
|
||||
</glossdef>
|
||||
<glossterm>WAL writer (process)</glossterm>
|
||||
<glossdef>
|
||||
<para>
|
||||
A process that writes <glossterm linkend="glossary-wal-record">WAL records</glossterm>
|
||||
from <glossterm linkend="glossary-shared-memory">shared memory</glossterm> to
|
||||
<glossterm linkend="glossary-wal-file">WAL files</glossterm>.
|
||||
</para>
|
||||
<para>
|
||||
For more information, see
|
||||
<xref linkend="runtime-config-wal"/>.
|
||||
</para>
|
||||
</glossdef>
|
||||
</glossentry>
|
||||
|
||||
<glossentry id="glossary-window-function">
|
||||
<glossterm>Window function</glossterm>
|
||||
<glossterm>Window function (routine)</glossterm>
|
||||
<glossdef>
|
||||
<para>
|
||||
A type of <glossterm linkend="glossary-function">function</glossterm> whose
|
||||
result is based on values found in
|
||||
<glossterm linkend="glossary-tuple">rows</glossterm> of the same
|
||||
<glossterm linkend="glossary-partition">partition</glossterm>.
|
||||
A type of <glossterm linkend="glossary-function">function</glossterm>
|
||||
used in a <glossterm linkend="glossary-query">query</glossterm>
|
||||
that applies to a <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>
|
||||
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.
|
||||
@ -1857,8 +1938,8 @@
|
||||
<glossdef>
|
||||
<para>
|
||||
The journal that keeps track of the changes in the
|
||||
<glossterm linkend="glossary-instance">instance</glossterm> as user- and
|
||||
system-invoked operations take place.
|
||||
<glossterm linkend="glossary-db-cluster">database cluster</glossterm>
|
||||
as user- and system-invoked operations take place.
|
||||
It comprises many individual
|
||||
<glossterm linkend="glossary-wal-record">WAL records</glossterm> written
|
||||
sequentially to <glossterm linkend="glossary-wal-file">WAL files</glossterm>.
|
||||
|
||||
Loading…
Reference in New Issue
Block a user