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-rw-r--r--doc/src/sgml/gin.sgml12
1 files changed, 9 insertions, 3 deletions
diff --git a/doc/src/sgml/gin.sgml b/doc/src/sgml/gin.sgml
index c2bbad42bfa..32919e58711 100644
--- a/doc/src/sgml/gin.sgml
+++ b/doc/src/sgml/gin.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/gin.sgml,v 2.7 2006/12/01 23:46:46 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/gin.sgml,v 2.8 2007/01/31 15:09:45 teodor Exp $ -->
<chapter id="GIN">
<title>GIN Indexes</title>
@@ -77,7 +77,7 @@
</varlistentry>
<varlistentry>
- <term>Datum* extractValue(Datum inputValue, uint32 *nkeys)</term>
+ <term>Datum* extractValue(Datum inputValue, int32 *nkeys)</term>
<listitem>
<para>
Returns an array of keys given a value to be indexed. The
@@ -87,7 +87,7 @@
</varlistentry>
<varlistentry>
- <term>Datum* extractQuery(Datum query, uint32 *nkeys,
+ <term>Datum* extractQuery(Datum query, int32 *nkeys,
StrategyNumber n)</term>
<listitem>
<para>
@@ -100,6 +100,12 @@
to consult <literal>n</> to determine the data type of
<literal>query</> and the key values that need to be extracted.
The number of returned keys must be stored into <literal>*nkeys</>.
+ If number of keys is equal to zero then <function>extractQuery</>
+ should store 0 or -1 into <literal>*nkeys</>. 0 means that any
+ row matches the <literal>query</> and sequence scan should be
+ produced. -1 means nothing can satisfy <literal>query</>.
+ Choice of value should be based on semantics meaning of operation with
+ given strategy number.
</para>
</listitem>
</varlistentry>