<chapter id="querymodel">
- <!-- $Id: querymodel.xml,v 1.26 2006-09-22 12:34:45 adam Exp $ -->
+ <!-- $Id: querymodel.xml,v 1.27 2006-11-30 10:33:19 adam Exp $ -->
<title>Query Model</title>
<section id="querymodel-overview">
<entry><literal>bib-1</literal></entry>
<entry>Standard PQF query language attribute set which defines the
semantics of Z39.50 searching. In addition, all of the
- non-use attributes (types 2-11) define the hard-wired
+ non-use attributes (types 2-12) define the hard-wired
Zebra internal query
processing.</entry>
<entry>default</entry>
</para>
<para>
Atomic (APT) queries are always leaf nodes in the PQF query tree.
- UN-supplied non-use attributes types 2-11 are either inherited from
+ UN-supplied non-use attributes types 2-12 are either inherited from
higher nodes in the query tree, or are set to Zebra's default values.
See <xref linkend="querymodel-bib1"/> for details.
</para>
model. These extensions are <emphasis>non-standard</emphasis>
and <emphasis>non-portable</emphasis>: most functional extensions
are modeled over the <literal>bib-1</literal> attribute set,
- defining type 7-9 attributes.
+ defining type 7 and higher values.
There are also the special
<literal>string</literal> type index names for the
<literal>idxpath</literal> attribute set.
<entry>1.1</entry>
</row>
<row>
- <entry>Approx Limit</entry>
- <entry>11</entry>
+ <entry>Term Reference</entry>
+ <entry>10</entry>
<entry>search</entry>
<entry>1.4</entry>
</row>
<row>
- <entry>Term Reference</entry>
- <entry>10</entry>
+ <entry>Local Approx Limit</entry>
+ <entry>11</entry>
<entry>search</entry>
<entry>1.4</entry>
</row>
+ <row>
+ <entry>Global Approx Limit</entry>
+ <entry>12</entry>
+ <entry>search</entry>
+ <entry>2.0.8</entry>
+ </row>
</tbody>
</tgroup>
</table>
Z> find @attr 2=102 @or @attr 9=30 @attr 1=4 utah @attr 9=20 utah
</screen>
</para>
- </section>
+ </section>
+
+ <section id="querymodel-zebra-attr-termref">
+ <title>Zebra Extension Term Reference Attribute (type 10)</title>
+ <para>
+ Zebra supports the searchResult-1 facility.
+ If the Term Reference Attribute (type 10) is
+ given, that specifies a subqueryId value returned as part of the
+ search result. It is a way for a client to name an APT part of a
+ query.
+ </para>
+ <!--
+ <para>
+ <screen>
+ </screen>
+ </para>
+ -->
+ <warning>
+ <para>
+ Experimental. Do not use in production code.
+ </para>
+ </warning>
+
+ </section>
+
+
- <section id="querymodel-zebra-attr-limit">
- <title>Zebra Extension Approximative Limit Attribute (type 11)</title>
+ <section id="querymodel-zebra-local-attr-limit">
+ <title>Local Approximative Limit Attribute (type 11)</title>
<para>
- Zebra computes - unless otherwise configured -
+ Zebra computes - unless otherwise configured -
the exact hit count for every APT
(leaf) in the query tree. These hit counts are returned as part of
the searchResult-1 facility in the binary encoded Z39.50 search
<para>
Do not use approximative hit count limits
in conjunction with relevance ranking, as re-sorting of the
- result set obviosly only works when the entire result set has
+ result set only works when the entire result set has
been processed.
</para>
</warning>
- <warning>
- <para>
- This facility clashes with rank weight, because there all
- documents in the hit lists need to be examined for scoring and
- re-sorting.
- It is an experimental
- extension. Do not use in production code.
- </para>
- </warning>
</section>
- <section id="querymodel-zebra-attr-termref">
- <title>Zebra Extension Term Reference Attribute (type 10)</title>
+ <section id="querymodel-zebra-global-attr-limit">
+ <title>Global Approximative Limit Attribute (type 12)</title>
<para>
- Zebra supports the searchResult-1 facility.
- If the Term Reference Attribute (type 10) is
- given, that specifies a subqueryId value returned as part of the
- search result. It is a way for a client to name an APT part of a
- query.
+ By default Zebra computes precise hit counts for a query as
+ a whole. Setting attribute 12 makes it perform approximative
+ hit counts instead. It has the same semantics as
+ <literal>estimatehits</literal> for the <xref linkend="zebra-cfg"/>.
</para>
- <!--
<para>
- <screen>
- </screen>
- </para>
- -->
+ The attribute (12) can occur anywhere in the query tree.
+ Unlike regular attributes it does not relate to the leaf (APT)
+ - but to the whole query.
+ </para>
<warning>
<para>
- Experimental. Do not use in production code.
- </para>
+ Do not use approximative hit count limits
+ in conjunction with relevance ranking, as re-sorting of the
+ result set only works when the entire result set has
+ been processed.
+ </para>
</warning>
-
</section>
+
</section>
-
<section id="querymodel-zebra-attr-scan">
<title>Zebra specific Scan Extensions to all Attribute Sets</title>
-/* $Id: rpnsearch.c,v 1.2 2006-10-12 12:28:42 adam Exp $
+/* $Id: rpnsearch.c,v 1.3 2006-11-30 10:33:19 adam Exp $
Copyright (C) 1995-2006
Index Data ApS
Z_Operator *parent_op,
struct rset_key_control *kc);
+ZEBRA_RES rpn_get_top_approx_limit(ZebraHandle zh, Z_RPNStructure *zs,
+ zint *approx_limit)
+{
+ ZEBRA_RES res = ZEBRA_OK;
+ if (zs->which == Z_RPNStructure_complex)
+ {
+ if (res == ZEBRA_OK)
+ res = rpn_get_top_approx_limit(zh, zs->u.complex->s1,
+ approx_limit);
+ if (res == ZEBRA_OK)
+ res = rpn_get_top_approx_limit(zh, zs->u.complex->s2,
+ approx_limit);
+ }
+ else if (zs->which == Z_RPNStructure_simple)
+ {
+ if (zs->u.simple->which == Z_Operand_APT)
+ {
+ Z_AttributesPlusTerm *zapt = zs->u.simple->u.attributesPlusTerm;
+ AttrType global_hits_limit_attr;
+ int l;
+
+ attr_init_APT(&global_hits_limit_attr, zapt, 12);
+
+ l = attr_find(&global_hits_limit_attr, NULL);
+ if (l != -1)
+ *approx_limit = l;
+ }
+ }
+ return res;
+}
+
ZEBRA_RES rpn_search_top(ZebraHandle zh, Z_RPNStructure *zs,
oid_value attributeSet,
NMEM stream, NMEM rset_nmem,
projects / idzebra-moved-to-github.git / commitdiff