Create a GUC parameter temp_tablespaces that allows selection of the

tablespace(s) in which to store temp tables and temporary files.  This is a
list to allow spreading the load across multiple tablespaces (a random list
element is chosen each time a temp object is to be created).  Temp files are
not stored in per-database pgsql_tmp/ directories anymore, but per-tablespace
directories.

Jaime Casanova and Albert Cervera, with review by Bernd Helmle and Tom Lane.

1 files changed, 12 insertions, 1 deletions

diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 9c3cf7589d..a66aeb2584 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/storage.sgml,v 1.17 2007/04/06 04:21:41 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/storage.sgml,v 1.18 2007/06/03 17:05:53 tgl Exp $ -->
 
 <chapter id="storage">
 
@@ -170,6 +170,17 @@ tablespace is not accessed through <filename>pg_tblspc</>, but corresponds to
 <varname>PGDATA</><filename>/global</>.
 </para>
 
+<para>
+Temporary files (for operations such as sorting more data than can fit in
+memory) are created within <varname>PGDATA</><filename>/base/pgsql_tmp</>,
+or within a <filename>pgsql_tmp</> subdirectory of a tablespace directory
+if a tablespace other than <literal>pg_default</> is specified for them.
+The name of a temporary file has the form
+<filename>pgsql_tmp<replaceable>PPP</>.<replaceable>NNN</></filename>,
+where <replaceable>PPP</> is the PID of the owning backend and
+<replaceable>NNN</> distinguishes different files of that backend.
+</para>
+
 </sect1>
 
 <sect1 id="storage-toast">