+ the number '0' (decreasing) or '1' (increasing). Default
+ sort order is decreasing.
+ Sort field names can be any field name designated as a sort field
+ in the pazpar2.cfg file, or the special names 'relevance' and
+ 'position'.
+ </para>
+ <para>
+ If not specified here or as
+ <link linkend="sort-default">sort-default"</link>
+ in pazpar2.cfg, pazpar2 will default to the built-in
+ 'relevance' ranking.
+ </para>
+ <para>
+ Having sort criteria at search is important for targets that
+ supports native sorting in order to get best results. pazpar2
+ will trigger a new search if search criteria changes from pazpar2
+ to target-based sorting.
+ </para>
+ <para>
+ For targets where If <link linkend="pzsortmap">pz:sortmap</link>
+ is defined, a sort operation will be executed (possibly including
+ extending the search).
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>mergekey</term>
+ <listitem>
+ <para>
+ Sets mergekey for this show and rest of session, or until
+ another mergekey is given for show/search. The mergekey value is a
+ comma separated list with one or more names as they appear
+ in the service description equivalent to
+ <literal>mergekey="optional"</literal> inside a metadata element.
+ If the empty string is given for mergekey it is disabled
+ and rest of session will use the default mergekey from service
+ or stylesheet.
+ </para>
+ <para>
+ This facility, "dynamic mergekey", appeared in Pazpar2 version
+ 1.6.31.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>rank</term>
+ <listitem>
+ <para>
+ Sets rank method this show and rest of session, or until
+ another rank is given for show/search. The rank value is a
+ comma separated list of pairs field=value pairs. The
+ format is the same as
+ <xref linkend="metadata-rank">rank</xref> for a metadata element.
+ If the empty string is given for rank it is disabled
+ and rest of session will use the default rank from metadata or
+ stylesheet.
+ </para>
+ <para>
+ This facility, "dynamic ranking", appeared in Pazpar2 version
+ 1.6.31.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>snippets</term>
+ <listitem>
+ <para>
+ If specified and set to 1 data will include snippets marked
+ with <match> tags. Otherwise snippets will not be included.
+ </para>
+ <para>
+ This facility, "snippets", appeared in Pazpar2 version
+ 1.6.32.