Add relation fork support to pg_relation_size() function. You can now pass

name of a fork ('main' or 'fsm', at the moment) to pg_relation_size() to
get the size of a specific fork. Defaults to 'main', if none given.

While we're at it, modify pg_relation_size to take a regclass as argument,
instead of separate variants taking oid and name. This change is
transparent to typical use where the table name is passed as a string
literal, like pg_relation_size('table'), but will break queries like
pg_relation_size(namecol), where namecol is of type name. text-type input
still works, and using a non-schema-qualified table name is not very
reliable anyway, so this is unlikely to break anyone's queries in practice.

1 files changed, 18 insertions, 20 deletions

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 05f0aabddd0..31ef6dc864d 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.447 2008/09/11 17:32:33 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.448 2008/10/03 07:33:08 heikki Exp $ -->
 
  <chapter id="functions">
   <title>Functions and Operators</title>
@@ -12417,7 +12417,7 @@ postgres=# select * from pg_xlogfile_name_offset(pg_stop_backup());
 
      <tbody>
       <row>
-       <entry><function>pg_column_size</function>(<type>any</type>)</entry>
+       <entry><literal><function>pg_column_size</function>(<type>any</type>)</literal></entry>
        <entry><type>int</type></entry>
        <entry>Number of bytes used to store a particular value (possibly compressed)</entry>
       </row>
@@ -12437,19 +12437,22 @@ postgres=# select * from pg_xlogfile_name_offset(pg_stop_backup());
       </row>
       <row>
        <entry>
-        <literal><function>pg_relation_size</function>(<type>oid</type>)</literal>
+        <literal><function>pg_relation_size</function>(<parameter>relation</parameter> <type>regclass</type>, <parameter>fork</parameter> <type>text</type>)</literal>
         </entry>
        <entry><type>bigint</type></entry>
-       <entry>Disk space used by the table or index with the specified OID</entry>
+       <entry>
+        Disk space used by the specified fork, <literal>'main'</literal> or
+        <literal>'fsm'</literal>, of a table or index with the specified OID
+        or name. The table name can be qualified with a schema name
+       </entry>
       </row>
       <row>
        <entry>
-        <literal><function>pg_relation_size</function>(<type>text</type>)</literal>
+        <literal><function>pg_relation_size</function>(<parameter>relation</parameter> <type>regclass</type>)</literal>
         </entry>
        <entry><type>bigint</type></entry>
        <entry>
-        Disk space used by the table or index with the specified name.
-        The table name can be qualified with a schema name
+        Shorthand for <literal>pg_relation_size(..., 'main')</literal>
        </entry>
       </row>
       <row>
@@ -12475,21 +12478,11 @@ postgres=# select * from pg_xlogfile_name_offset(pg_stop_backup());
       </row>
       <row>
        <entry>
-        <literal><function>pg_total_relation_size</function>(<type>oid</type>)</literal>
-        </entry>
-       <entry><type>bigint</type></entry>
-       <entry>
-        Total disk space used by the table with the specified OID,
-        including indexes and toasted data
-       </entry>
-      </row>
-      <row>
-       <entry>
-        <literal><function>pg_total_relation_size</function>(<type>text</type>)</literal>
+        <literal><function>pg_total_relation_size</function>(<type>regclass</type>)</literal>
         </entry>
        <entry><type>bigint</type></entry>
        <entry>
-        Total disk space used by the table with the specified name,
+        Total disk space used by the table with the specified OID or name,
         including indexes and toasted data.  The table name can be
         qualified with a schema name
        </entry>
@@ -12511,7 +12504,12 @@ postgres=# select * from pg_xlogfile_name_offset(pg_stop_backup());
 
    <para>
     <function>pg_relation_size</> accepts the OID or name of a table, index or
-    toast table, and returns the size in bytes.
+    toast table, and returns the size in bytes. Specifying
+    <literal>'main'</literal> or leaving out the second argument returns the
+    size of the main data fork of the relation. Specifying
+    <literal>'fsm'</literal> returns the size of the
+    Free Space Map (see <xref linkend="storage-fsm">) associated with the
+    relation.
    </para>
 
    <para>