From 5bba4948eb835413cc4a5ca1e2f7255ce4c78e69 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Fri, 18 Feb 2011 22:39:17 -0500
Subject: [PATCH] Document that text search comparisons happen after text
search configuration rules.
Erik Rijkers
---
doc/src/sgml/datatype.sgml | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml
index 2bf411d9e22..10f0e590d79 100644
--- a/doc/src/sgml/datatype.sgml
+++ b/doc/src/sgml/datatype.sgml
@@ -3847,7 +3847,28 @@ SELECT 'super:*'::tsquery;
'super':*
</programlisting>
This query will match any word in a <type>tsvector</> that begins
- with <quote>super</>.
+ with <quote>super</>.
+ </para>
+
+ <para>
+ Note that text search configuration processing happens before
+ comparisons, which means this comparison returns <literal>true</>:
+<programlisting>
+SELECT to_tsvector( 'postgraduate' ) @@ to_tsquery( 'postgres:*' );
+ ?column?
+----------
+ t
+(1 row)
+</programlisting>
+ because <literal>postgres</> gets stemmed to <literal>postgr</>:
+<programlisting>
+SELECT to_tsquery('postgres:*');
+ to_tsquery
+------------
+ 'postgr':*
+(1 row)
+</programlisting>
+ which then matches <literal>postgraduate</>.
</para>
<para>
--
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