amend ST_Mem_Size

git-svn-id: http://svn.osgeo.org/postgis/trunk@3300 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/doc/reference_new.xml b/doc/reference_new.xml
index 64ee2bc5932e39a65994a503eddbc068daebcc35..653f363195880ddccbeb015311485e09166519e7 100644 (file)
--- a/doc/reference_new.xml
+++ b/doc/reference_new.xml
@@ -10629,9 +10629,11 @@ SELECT ST_SetSRID(ST_Extent(the_geom),2249) as bextent FROM sometable;
            <title>Description</title>
        
            <para>Returns the amount of space (in bytes) the geometry takes. </para>
-               <para>This is a nice compliment to PostgreSQL built in functions pg_size_pretty, pg_relation_size.</para>
-               <note><para>pg_relation_size which gives the full size of a table may return byte size lower than ST_Mem_Size. This is because
-               pg_relation_size does not add toasted table contribution where large geometries are stored.</para></note>
+               <para>This is a nice compliment to PostgreSQL built in functions pg_size_pretty, pg_relation_size, pg_total_relation_size.</para>
+               <note><para>pg_relation_size which gives the byte size of a table may return byte size lower than ST_Mem_Size. This is because
+               pg_relation_size does not add toasted table contribution and large geometries are stored in TOAST tables.</para>
+               <para>pg_total_relation_size - includes, the table, the toasted tables, and the indexes.</para>
+               </note>
                
        
                <!-- Optionally mention 3d support -->
@@ -10670,6 +10672,13 @@ SELECT ST_Mem_Size(ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 150505,2
 ---
 73
        
+--What percentage of our table is taken up by just the geometry
+SELECT pg_total_relation_size('public.neighborhoods') As fulltable_size, sum(ST_Mem_Size(the_geom)) As geomsize,
+sum(ST_Mem_Size(the_geom))*1.00/pg_total_relation_size('public.neighborhoods')*100 As pergeom
+FROM neighborhoods;
+fulltable_size geomsize  pergeom       
+------------------------------------------------
+262144         96238    36.71188354492187500000
        </programlisting>
          </refsection>