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Support unlogged tables.

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The contents of an unlogged table are WAL-logged; thus, they are not
available on standby servers and are truncated whenever the database
system enters recovery.  Indexes on unlogged tables are also unlogged.
Unlogged GiST indexes are not currently supported.
This commit is contained in:
Robert Haas
2010-12-29 06:48:53 -05:00
parent 9b8aff8c19
commit 53dbc27c62
49 changed files with 916 additions and 104 deletions
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3
doc/src/sgml/catalogs.sgml
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@ -1644,7 +1644,8 @@
<entry><type>bool</type></entry>
<entry></entry>
<entry>
<literal>p</> = permanent table, <literal>t</> = temporary table
<literal>p</> = permanent table, <literal>u</> = unlogged table,
<literal>t</> = temporary table
</entry>
</row>

11
doc/src/sgml/indexam.sgml
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@ -167,6 +167,17 @@ ambuild (Relation heapRelation,
<para>
<programlisting>
void
ambuildempty (Relation indexRelation);
</programlisting>
Build an empty index, and write it to the initialization fork (INIT_FORKNUM)
of the given relation. This method is called only for unlogged tables; the
empty index written to the initialization fork will be copied over the main
relation fork on each server restart.
</para>
<para>
<programlisting>
bool
aminsert (Relation indexRelation,
Datum *values,

21
doc/src/sgml/ref/create_table.sgml
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@ -21,7 +21,7 @@ PostgreSQL documentation
<refsynopsisdiv>
<synopsis>
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name</replaceable> ( [
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name</replaceable> ( [
{ <replaceable class="PARAMETER">column_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
| <replaceable>table_constraint</replaceable>
| LIKE <replaceable>parent_table</replaceable> [ <replaceable>like_option</replaceable> ... ] }
@ -32,7 +32,7 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE [ IF NOT EXISTS ] <repl
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE <replaceable class="PARAMETER">tablespace</replaceable> ]
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name</replaceable>
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name</replaceable>
OF <replaceable class="PARAMETER">type_name</replaceable> [ (
{ <replaceable class="PARAMETER">column_name</replaceable> WITH OPTIONS [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
| <replaceable>table_constraint</replaceable> }
@ -164,6 +164,23 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE [ IF NOT EXISTS ] <repl
</listitem>
</varlistentry>
<varlistentry>
<term><literal>UNLOGGED</></term>
<listitem>
<para>
If specified, the table is created as an unlogged table. Data written
to unlogged tables is not written to the write-ahead log (see <xref
linkend="wal">), which makes them considerably faster than ordinary
tables. However, they are not crash-safe: an unlogged table is
automatically truncated after a crash or unclean shutdown. The contents
of an unlogged table are also not replicated to standby servers.
Any indexes created on an unlogged table are automatically unlogged as
well; however, unlogged <link linkend="GiST">GiST indexes</link> are
currently not supported and cannot be created on an unlogged table.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>IF NOT EXISTS</></term>
<listitem>

12
doc/src/sgml/ref/create_table_as.sgml
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@ -21,7 +21,7 @@ PostgreSQL documentation
<refsynopsisdiv>
<synopsis>
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE <replaceable>table_name</replaceable>
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE <replaceable>table_name</replaceable>
[ (<replaceable>column_name</replaceable> [, ...] ) ]
[ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> [= <replaceable class="PARAMETER">value</replaceable>] [, ... ] ) | WITH OIDS | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
@ -81,6 +81,16 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE <replaceable>table_name
</listitem>
</varlistentry>
<varlistentry>
<term><literal>UNLOGGED</></term>
<listitem>
<para>
If specified, the table is created as an unlogged table.
Refer to <xref linkend="sql-createtable"> for details.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable>table_name</replaceable></term>
<listitem>

11
doc/src/sgml/ref/pg_dump.sgml
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@ -669,6 +669,17 @@ PostgreSQL documentation
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-unlogged-table-data</option></term>
<listitem>
<para>
Do not dump the contents of unlogged tables. This option has no
effect on whether or not the table definitions (schema) are dumped;
it only suppresses dumping the table data.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--quote-all-identifiers</></term>
<listitem>

11
doc/src/sgml/ref/pg_dumpall.sgml
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@ -201,6 +201,17 @@ PostgreSQL documentation
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-unlogged-table-data</option></term>
<listitem>
<para>
Do not dump the contents of unlogged tables. This option has no
effect on whether or not the table definitions (schema) are dumped;
it only suppresses dumping the table data.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-r</option></term>
<term><option>--roles-only</option></term>

22
doc/src/sgml/storage.sgml
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@ -147,7 +147,9 @@ the relation. The free space map is stored in a file named with the filenode
number plus the suffix <literal>_fsm</>. Tables also have a
<firstterm>visibility map</>, stored in a fork with the suffix <literal>_vm</>,
to track which pages are known to have no dead tuples. The visibility map is
described further in <xref linkend="storage-vm">.
described further in <xref linkend="storage-vm">. Unlogged tables and indexes
have a third fork, known as the initialization fork, which is stored in a fork
with the suffix <literal>_init</literal> (see <xref linkend="storage-init">).
</para>
<caution>
@ -485,6 +487,24 @@ a bit is not set, it might or might not be true.
</sect1>
<sect1 id="storage-init">
<title>The Initialization Fork</title>
<indexterm>
<primary>Initialization Fork</primary>
</indexterm>
<para>
Each unlogged table, and each index on an unlogged table, has an initialization
fork. The initialization fork is an empty table or index of the appropriate
type. When an unlogged table must be reset to empty due to a crash, the
initialization fork is copied over the main fork, and any other forks are
erased (they will be recreated automatically as needed).
</para>
</sect1>
<sect1 id="storage-page-layout">
<title>Database Page Layout</title>