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Migrate the former contrib/txid module into core. This will make it easier

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for Slony and Skytools to depend on it.  Per discussion.
This commit is contained in:
Tom Lane
2007-10-13 23:06:28 +00:00
parent 17333b6d09
commit 18e3fcc31e
12 changed files with 1007 additions and 21 deletions
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8
doc/src/sgml/datatype.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.209 2007/08/31 04:52:29 momjian Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.210 2007/10/13 23:06:26 tgl Exp $ -->
<chapter id="datatype">
<title id="datatype-title">Data Types</title>
@ -246,6 +246,12 @@
<entry>full text search document</entry>
</row>
<row>
<entry><type>txid_snapshot</type></entry>
<entry></entry>
<entry>user-level transaction ID snapshot</entry>
</row>
<row>
<entry><type>uuid</type></entry>
<entry></entry>

80
doc/src/sgml/func.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.400 2007/10/11 02:43:55 momjian Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.401 2007/10/13 23:06:26 tgl Exp $ -->
<chapter id="functions">
<title>Functions and Operators</title>
@ -12048,6 +12048,84 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
databases within each cluster and their descriptions are stored globally
as well.
</para>
<indexterm>
<primary>txid_current</primary>
</indexterm>
<indexterm>
<primary>txid_current_snapshot</primary>
</indexterm>
<indexterm>
<primary>txid_snapshot_xmin</primary>
</indexterm>
<indexterm>
<primary>txid_snapshot_xmax</primary>
</indexterm>
<indexterm>
<primary>txid_snapshot_xip</primary>
</indexterm>
<indexterm>
<primary>txid_visible_in_snapshot</primary>
</indexterm>
<para>
The functions shown in <xref linkend="functions-txid-snapshot">
export server internal transaction info to user level.
</para>
<table id="functions-txid-snapshot">
<title>Transaction IDs and snapshots</title>
<tgroup cols="3">
<thead>
<row><entry>Name</entry> <entry>Return Type</entry> <entry>Description</entry></row>
</thead>
<tbody>
<row>
<entry><literal><function>txid_current</function>()</literal></entry>
<entry><type>bigint</type></entry>
<entry>get current transaction ID</entry>
</row>
<row>
<entry><literal><function>txid_current_snapshot</function>()</literal></entry>
<entry><type>txid_snapshot</type></entry>
<entry>get current snapshot</entry>
</row>
<row>
<entry><literal><function>txid_snapshot_xmin</function>(<parameter>txid_snapshot</parameter>)</literal></entry>
<entry><type>bigint</type></entry>
<entry>get xmin of snapshot</entry>
</row>
<row>
<entry><literal><function>txid_snapshot_xmax</function>(<parameter>txid_snapshot</parameter>)</literal></entry>
<entry><type>bigint</type></entry>
<entry>get xmax of snapshot</entry>
</row>
<row>
<entry><literal><function>txid_snapshot_xip</function>(<parameter>txid_snapshot</parameter>)</literal></entry>
<entry><type>setof bigint</type></entry>
<entry>get in-progress transaction IDs in snapshot</entry>
</row>
<row>
<entry><literal><function>txid_visible_in_snapshot</function>(<parameter>bigint</parameter>, <parameter>txid_snapshot</parameter>)</literal></entry>
<entry><type>boolean</type></entry>
<entry>is transaction ID visible in snapshot?</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
The internal transaction ID type (<type>xid</>) is 32 bits wide and so
it wraps around every 4 billion transactions. However, these functions
export a 64-bit format that is extended with an <quote>epoch</> counter
so that it will not wrap around for the life of an installation.
</para>
</sect1>
<sect1 id="functions-admin">