diff options
Diffstat (limited to 'doc/src/sgml/catalogs.sgml')
| -rw-r--r-- | doc/src/sgml/catalogs.sgml | 94 |
1 files changed, 91 insertions, 3 deletions
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 41d7a4e34d5..c5473b9501b 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -1,6 +1,6 @@ <!-- Documentation of the system catalogs, directed toward PostgreSQL developers - $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.103 2005/06/13 23:14:47 tgl Exp $ + $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.104 2005/06/17 22:32:41 tgl Exp $ --> <chapter id="catalogs"> @@ -3933,6 +3933,11 @@ </row> <row> + <entry><link linkend="view-pg-prepared-xacts"><structname>pg_prepared_xacts</structname></link></entry> + <entry>currently prepared transactions</entry> + </row> + + <row> <entry><link linkend="view-pg-rules"><structname>pg_rules</structname></link></entry> <entry>rules</entry> </row> @@ -4167,8 +4172,10 @@ <entry><structfield>pid</structfield></entry> <entry><type>integer</type></entry> <entry></entry> - <entry>process ID of the server process holding or awaiting this - lock</entry> + <entry> + Process ID of the server process holding or awaiting this + lock. Zero if the lock is held by a prepared transaction. + </entry> </row> <row> <entry><structfield>mode</structfield></entry> @@ -4250,6 +4257,87 @@ </sect1> + <sect1 id="view-pg-prepared-xacts"> + <title><structname>pg_prepared_xacts</structname></title> + + <indexterm zone="view-pg-prepared-xacts"> + <primary>pg_prepared_xacts</primary> + </indexterm> + + <para> + The view <structname>pg_prepared_xacts</structname> displays + information about transactions that are currently prepared for two-phase + commit (see <xref linkend="sql-prepare-transaction" + endterm="sql-prepare-transaction-title"> for details). + </para> + + <para> + <structname>pg_prepared_xacts</structname> contains one row per prepared + transaction. An entry is removed when the transaction is committed or + rolled back. + </para> + + <table> + <title><structname>pg_prepared_xacts</> Columns</title> + + <tgroup cols=4> + <thead> + <row> + <entry>Name</entry> + <entry>Type</entry> + <entry>References</entry> + <entry>Description</entry> + </row> + </thead> + <tbody> + <row> + <entry><structfield>transaction</structfield></entry> + <entry><type>xid</type></entry> + <entry></entry> + <entry> + Numeric transaction identifier of the prepared transaction + </entry> + </row> + <row> + <entry><structfield>gid</structfield></entry> + <entry><type>text</type></entry> + <entry></entry> + <entry> + Global transaction identifier that was assigned to the transaction + </entry> + </row> + <row> + <entry><structfield>owner</structfield></entry> + <entry><type>name</type></entry> + <entry><literal><link linkend="catalog-pg-shadow"><structname>pg_shadow</structname></link>.usename</literal></entry> + <entry> + Name of the user that executed the transaction + </entry> + </row> + <row> + <entry><structfield>database</structfield></entry> + <entry><type>name</type></entry> + <entry><literal><link linkend="catalog-pg-database"><structname>pg_database</structname></link>.datname</literal></entry> + <entry> + Name of the database in which the transaction was executed + </entry> + </row> + </tbody> + </tgroup> + </table> + + <para> + When the <structname>pg_prepared_xacts</structname> view is accessed, the + internal transaction manager data structures are momentarily locked, and + a copy is made for the view to display. This ensures that the + view produces a consistent set of results, while not blocking + normal operations longer than necessary. Nonetheless + there could be some impact on database performance if this view is + read often. + </para> + + </sect1> + <sect1 id="view-pg-rules"> <title><structname>pg_rules</structname></title> |