<chapter id="administration">
- <!-- $Id: administration.xml,v 1.13 2002-12-02 15:10:58 mike Exp $ -->
+ <!-- $Id: administration.xml,v 1.32 2006-05-02 12:23:02 mike Exp $ -->
<title>Administrating Zebra</title>
<!-- ### It's a bit daft that this chapter (which describes half of
the configuration-file formats) is separated from
- "recordmodel.xml" (which describes the other half) by the
+ "recordmodel-grs.xml" (which describes the other half) by the
instructions on running zebraidx and zebrasrv. Some careful
re-ordering is required here.
-->
Specifies <replaceable>size</replaceable> of internal memory
to use for the zebraidx program.
The amount is given in megabytes - default is 4 (4 MB).
+ The more memory, the faster large updates happen, up to about
+ half the free memory available on the computer.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>tempfiles: <replaceable>Yes/Auto/No</replaceable></term>
+ <listitem>
+ <para>
+ Tells zebra if it should use temporary files when indexing. The
+ default is Auto, in which case zebra uses temporary files only
+ if it would need more that <replaceable>memMax</replaceable>
+ megabytes of memory. This should be good for most uses.
</para>
</listitem>
</varlistentry>
</varlistentry>
<varlistentry>
- <term>tagsysno: 0|1</term>
+ <term>passwd: <replaceable>file</replaceable></term>
+ <listitem>
+ <para>
+ Specifies a file with description of user accounts for Zebra.
+ The format is similar to that known to Apache's htpasswd files
+ and UNIX' passwd files. Non-empty lines not beginning with
+ # are considered account lines. There is one account per-line.
+ A line consists of fields separate by a single colon character.
+ First field is username, second is password.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>passwd.c: <replaceable>file</replaceable></term>
+ <listitem>
+ <para>
+ Specifies a file with description of user accounts for Zebra.
+ File format is similar to that used by the passwd directive except
+ that the password are encrypted. Use Apache's htpasswd or similar
+ for maintenanace.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>perm.<replaceable>user</replaceable>:
+ <replaceable>permstring</replaceable></term>
<listitem>
<para>
- Species whether Zebra should include system-number data in XML
- and GRS-1 records returned to clients, represented by the
- <literal><localControlNumber></literal> element in XML
- and the <literal>(1,14)</literal> tag in GRS-1.
- The content of these elements is an internally-generated
- integer uniquely identifying the record within its database.
- It is included by default but may be turned off, with
- <literal>tagsysno: 0</literal> for databases in which a local
- control number is explicitly specified in the input records
- themselves.
+ Specifies permissions (priviledge) for a user that are allowed
+ to access Zebra via the passwd system. There are two kinds
+ of permissions currently: read (r) and write(w). By default
+ users not listed in a permission directive are given the read
+ priviledge. To specify permissions for a user with no
+ username, or Z39.50 anonymous style use
+ <literal>anonymous</literal>. The permstring consists of
+ a sequence of characters. Include character <literal>w</literal>
+ for write/update access, <literal>r</literal> for read access.
</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term>dbaccess <replaceable>accessfile</replaceable></term>
+ <listitem>
+ <para>
+ Names a file which lists database subscriptions for individual users.
+ The access file should consists of lines of the form <literal>username:
+ dbnames</literal>, where dbnames is a list of database names, seprated by
+ '+'. No whitespace is allowed in the database list.
+ </para>
+ </listitem>
+ </varlistentry>
+
</variablelist>
</para>
<para>
<screen>
- profilePath: /usr/local/yaz
+ profilePath: /usr/local/idzebra/tab
attset: bib1.att
simple.recordType: text
simple.database: textbase
</para>
<para>
- (see <xref linkend="data-model"/>
+ (see <xref linkend="record-model-grs"/>
for details of how the mapping between elements of your records and
searchable attributes is established).
</para>
<screen>
register: /d1:500M
-
shadow: /scratch1:100M /scratch2:200M
</screen>
</sect2>
</sect1>
+
+
+ <sect1 id="administration-ranking">
+ <title>Relevance Ranking and Sorting of Result Sets</title>
+
+ <sect2>
+ <title>Overview</title>
+ <para>
+ The default ordering of a result set is left up to the server,
+ which inside Zebra means sorting in ascending document ID order.
+ This is not always the order humans want to browse the sometimes
+ quite large hit sets. Ranking and sorting comes to the rescue.
+ </para>
+
+ <para>
+ In cases where a good presentation ordering can be computed at
+ indexing time, we can use a fixed <literal>static ranking</literal>
+ scheme, which is provided for the <literal>alvis</literal>
+ indexing filter. This defines a fixed ordering of hit lists,
+ independently of the query issued.
+ </para>
+
+ <para>
+ There are cases, however, where relevance of hit set documents is
+ highly dependent on the query processed.
+ Simply put, <literal>dynamic relevance ranking</literal>
+ sorts a set of retrieved
+ records such
+ that those most likely to be relevant to your request are
+ retrieved first.
+ Internally, Zebra retrieves all documents that satisfy your
+ query, and re-orders the hit list to arrange them based on
+ a measurement of similarity between your query and the content of
+ each record.
+ </para>
+
+ <para>
+ Finally, there are situations where hit sets of documents should be
+ <literal>sorted</literal> during query time according to the
+ lexicographical ordering of certain sort indexes created at
+ indexing time.
+ </para>
+ </sect2>
+
+
+ <sect2 id="administration-ranking-static">
+ <title>Static Ranking</title>
+
+ <para>
+ Zebra uses internally inverted indexes to look up term occurencies
+ in documents. Multiple queries from different indexes can be
+ combined by the binary boolean operations <literal>AND</literal>,
+ <literal>OR</literal> and/or <literal>NOT</literal> (which
+ is in fact a binary <literal>AND NOT</literal> operation).
+ To ensure fast query execution
+ speed, all indexes have to be sorted in the same order.
+ </para>
+ <para>
+ The indexes are normally sorted according to document
+ <literal>ID</literal> in
+ ascending order, and any query which does not invoke a special
+ re-ranking function will therefore retrieve the result set in
+ document
+ <literal>ID</literal>
+ order.
+ </para>
+ <para>
+ If one defines the
+ <screen>
+ staticrank: 1
+ </screen>
+ directive in the main core Zebra config file, the internal document
+ keys used for ordering are augmented by a preceeding integer, which
+ contains the static rank of a given document, and the index lists
+ are ordered
+ first by ascending static rank,
+ then by ascending document <literal>ID</literal>.
+ Zero
+ is the ``best'' rank, as it occurs at the
+ beginning of the list; higher numbers represent worse scores.
+ </para>
+ <para>
+ The experimental <literal>alvis</literal> filter provides a
+ directive to fetch static rank information out of the indexed XML
+ records, thus making <emphasis>all</emphasis> hit sets orderd
+ after <emphasis>ascending</emphasis> static
+ rank, and for those doc's which have the same static rank, ordered
+ after <emphasis>ascending</emphasis> doc <literal>ID</literal>.
+ See <xref linkend="record-model-alvisxslt"/> for the gory details.
+ </para>
+ </sect2>
+
+
+ <sect2 id="administration-ranking-dynamic">
+ <title>Dynamic Ranking</title>
+ <para>
+ In order to fiddle with the static rank order, it is necessary to
+ invoke additional re-ranking/re-ordering using dynamic
+ ranking or score functions. These functions return positive
+ integer scores, where <emphasis>highest</emphasis> score is
+ ``best'';
+ hit sets are sorted according to
+ <emphasis>decending</emphasis>
+ scores (in contrary
+ to the index lists which are sorted according to
+ ascending rank number and document ID).
+ </para>
+ <para>
+ Dynamic ranking is enabled by a directive like one of the
+ following in the zebra config file (use only one of these a time!):
+ <screen>
+ rank: rank-1 # default TDF-IDF like
+ rank: rank-static # dummy do-nothing
+ rank: zvrank # configurable, experimental TDF-IDF like
+ </screen>
+ Notice that the <literal>rank-1</literal> and
+ <literal>zvrank</literal> do not use the static rank
+ information in the list keys, and will produce the same ordering
+ with or without static ranking enabled.
+ </para>
+ <para>
+ The dummy <literal>rank-static</literal> reranking/scoring
+ function returns just
+ <literal>score = max int - staticrank</literal>
+ in order to preserve the static ordering of hit sets that would
+ have been produced had it not been invoked.
+ Obviously, to combine static and dynamic ranking usefully,
+ it is necessary
+ to make a new ranking
+ function; this is left
+ as an exercise for the reader.
+ </para>
+
+
+ <para>
+ Dynamic ranking is done at query time rather than
+ indexing time (this is why we
+ call it ``dynamic ranking'' in the first place ...)
+ It is invoked by adding
+ the Bib-1 relation attribute with
+ value ``relevance'' to the PQF query (that is,
+ <literal>@attr 2=102</literal>, see also
+ <ulink url="ftp://ftp.loc.gov/pub/z3950/defs/bib1.txt">
+ The BIB-1 Attribute Set Semantics</ulink>).
+ To find all articles with the word <literal>Eoraptor</literal> in
+ the title, and present them relevance ranked, issue the PQF query:
+ <screen>
+ @attr 2=102 @attr 1=4 Eoraptor
+ </screen>
+ </para>
+
+ <para>
+ The default <literal>rank-1</literal> ranking module implements a
+ TF-IDF (Term Frequecy over Inverse Document Frequency) like algorithm.
+ </para>
+
+ <warning>
+ <para>
+ Notice that <literal>dynamic ranking</literal> is not compatible
+ with <literal>estimated hit sizes</literal>, as all documents in
+ a hit set must be acessed to compute the correct placing in a
+ ranking sorted list. Therefore the use attribute setting
+ <literal>@attr 2=102</literal> clashes with
+ <literal>@attr 9=integer</literal>.
+ </para>
+ </warning>
+
+ <para>
+ It is possible to apply dynamic ranking on parts of the PQF query
+ allone:
+ <screen>
+ Z> f @and @attr 2=102 @attr 1=1010 Utah @attr 1=1018 Springer
+ </screen>
+ searches for all documents which have the term 'Utah' on the
+ body of text, and which have the term 'Springer' in the publisher
+ field, and sort them in the order of the relvance ranking made on
+ the body of text index only.
+ </para>
+ <para>
+ Rank weight is a way to pass a value to a ranking algorithm - so that
+ one APT has one value - while another as a different one. For
+ example, we can
+ search for 'utah' in use attribute set 'title' with weight 30, as
+ well as in use attribute set 'any' with weight 20.
+ <screen>
+ Z> f @attr 2=102 @or @attr 9=30 @attr 1=4 utah @attr 9=20 utah
+ </screen>
+ </para>
+ <warning>
+ <para>
+ The rank weight feature is experimental. It may change in future
+ releases of zebra, and is not production mature.
+ </para>
+ </warning>
+
+ <para>
+ Notice that <literal>dynamic ranking</literal> can be enabled in
+ sever side CQL query expansion by adding <literal>@attr
+ 2=102</literal> to the CQL config file. For example
+ <screen>
+ relationModifier.relevant = 2=102
+ </screen>
+ invokes dynamik ranking each time a CQL query of the form
+ <screen>
+ Z> querytype cql
+ Z> f alvis.text =/relevant house
+ </screen>
+ is issued. Dynamic ranking can be enabled on specific CQL indexes
+ by (for example) setting
+ <screen>
+ index.alvis.text = 1=text 2=102
+ </screen>
+ which then invokes dynamik ranking each time a CQL query of the form
+ <screen>
+ Z> querytype cql
+ Z> f alvis.text = house
+ </screen>
+ is issued.
+ </para>
+
+ </sect2>
+
+
+ <sect2 id="administration-ranking-sorting">
+ <title>Sorting</title>
+ <para>
+ Sorting is enabled in the configuration of record indexing. For
+ example, to enable sorting according to the BIB-1
+ <literal>Date/time-added-to-db</literal> field, one could add the line
+ <screen>
+ xelm /*/@created Date/time-added-to-db:s
+ </screen>
+ to any <literal>.abs</literal> record indexing config file, or
+ similarily, one could add an indexing element of the form
+ <screen><![CDATA[
+ <z:index name="date-modified" type="s">
+ <xsl:value-of select="some/xpath"/>
+ </z:index>
+ ]]></screen>
+ to any <literal>alvis</literal> indexing rule.
+ </para>
+ <para>
+ To trigger a sorting on a pre-defined sorting index of type
+ <literal>s</literal>, we can issue a sort with BIB-1
+ embedded sort attribute set <literal>7</literal>.
+ The embedded sort is a way to specify sort within a query - thus
+ removing the need to send a Z39.50 <literal>Sort
+ Request</literal> separately.
+ </para>
+ <para>
+ The value after attribute type <literal>7</literal> is
+ <literal>1</literal> (=ascending), or <literal>2</literal>
+ (=descending).
+ The attributes+term (APT) node is separate from the rest of the
+ PQF query, and must be <literal>@or</literal>'ed.
+ The term associated with this attribute is the sorting level,
+ where
+ <literal>0</literal> specifies the primary sort key,
+ <literal>1</literal> the secondary sort key, and so on.
+ </para>
+ <para>For example, a search for water, sort by title (ascending),
+ is expressed by the PQF query
+ <screen>
+ Z> f @or @attr 1=1016 water @attr 7=1 @attr 1=4 0
+ </screen>
+ whereas a search for water, sort by title ascending,
+ then date descending would be
+ <screen>
+ Z> f @or @or @attr 1=1016 water @attr 7=1 @attr 1=4 0 @attr 7=2 @attr 1=30 1
+ </screen>
+ </para>
+ <para>
+ Notice the fundamental differences between <literal>dynamic
+ ranking</literal> and <literal>sorting</literal>: there can only
+ be one ranking function defined and configured, but there can be
+ specified multiple sorting indexes dynamically at search
+ time. Ranking does not need to use specific indexes, which means,
+ dynamic ranking can be enabled and disabled without
+ re-indexing. On the other hand, sorting indexes need to be
+ defined before indexing.
+ </para>
+
+ </sect2>
+
+
+ </sect1>
+
+ <sect1 id="administration-extended-services">
+ <title>Extended Services: Remote Insert, Update and Delete</title>
+
+ <para>
+ The extended services are not enabled by default in zebra - due to the
+ fact that they modify the system.
+ In order to allow anybody to update, use
+ <screen>
+ perm.anonymous: rw
+ </screen>
+ in the main zebra configuration file <filename>zebra.cfg</filename>.
+ Or, even better, allow only updates for a particular admin user. For
+ user <literal>admin</literal>, you could use:
+ <screen>
+ perm.admin: rw
+ passwd: passwordfile
+ </screen>
+ And in <filename>passwordfile</filename>, specify users and
+ passwords as colon seperated strings:
+ <screen>
+ admin:secret
+ </screen>
+ </para>
+ <para>
+ We can now start a yaz-client admin session and create a database:
+ <screen>
+ <![CDATA[
+ $ yaz-client localhost:9999 -u admin/secret
+ Z> adm-create
+ ]]>
+ </screen>
+ Now the <literal>Default</literal> database was created,
+ we can insert an XML file (esdd0006.grs
+ from example/gils/records) and index it:
+ <screen>
+ <![CDATA[
+ Z> update insert 1 esdd0006.grs
+ ]]>
+ </screen>
+ The 3rd parameter - <literal>1</literal> here -
+ is the opaque record ID from <literal>Ext update</literal>.
+ It a record ID that <emphasis>we</emphasis> assign to the record
+ in question. If we do not
+ assign one, the usual rules for match apply (recordId: from zebra.cfg).
+ </para>
+ <para>
+ Actually, we should have a way to specify "no opaque record id" for
+ yaz-client's update command.. We'll fix that.
+ </para>
+ <para>
+ The newly inserted record can be searched as usual:
+ <screen>
+ <![CDATA[
+ Z> f utah
+ Sent searchRequest.
+ Received SearchResponse.
+ Search was a success.
+ Number of hits: 1, setno 1
+ SearchResult-1: term=utah cnt=1
+ records returned: 0
+ Elapsed: 0.014179
+ ]]>
+ </screen>
+ </para>
+ <para>
+ Let's delete the beast:
+ <screen>
+ <![CDATA[
+ Z> update delete 1
+ No last record (update ignored)
+ Z> update delete 1 esdd0006.grs
+ Got extended services response
+ Status: done
+ Elapsed: 0.072441
+ Z> f utah
+ Sent searchRequest.
+ Received SearchResponse.
+ Search was a success.
+ Number of hits: 0, setno 2
+ SearchResult-1: term=utah cnt=0
+ records returned: 0
+ Elapsed: 0.013610
+ ]]>
+ </screen>
+ </para>
+ <para>
+ If shadow register is enabled in your
+ <filename>zebra.cfg</filename>,
+ you must run the adm-commit command
+ <screen>
+ <![CDATA[
+ Z> adm-commit
+ ]]>
+ </screen>
+ after each update session in order write your changes from the
+ shadow to the life register space.
+ </para>
+ <para>
+ Extended services are also available from the YAZ client layer. An
+ example of an YAZ-PHP extended service transaction is given here:
+ <screen>
+ <![CDATA[
+ $record = '<record><title>A fine specimen of a record</title></record>';
+
+ $options = array('action' => 'recordInsert',
+ 'syntax' => 'xml',
+ 'record' => $record,
+ 'databaseName' => 'mydatabase'
+ );
+
+ yaz_es($yaz, 'update', $options);
+ yaz_es($yaz, 'commit', array());
+ yaz_wait();
+
+ if ($error = yaz_error($yaz))
+ echo "$error";
+ ]]>
+ </screen>
+ The <literal>action</literal> parameter can be any of
+ <literal>recordInsert</literal> (will fail if the record already exists),
+ <literal>recordReplace</literal> (will fail if the record does not exist),
+ <literal>recordDelete</literal> (will fail if the record does not
+ exist), and
+ <literal>specialUpdate</literal> (will insert or update the record
+ as needed).
+ </para>
+ <para>
+ If a record is inserted
+ using the action <literal>recordInsert</literal>
+ one can specify the optional
+ <literal>recordIdOpaque</literal> parameter, which is a
+ client-supplied, opaque record identifier. This identifier will
+ replace zebra's own automagic identifier generation.
+ </para>
+ <para>
+ When using the action <literal>recordReplace</literal> or
+ <literal>recordDelete</literal>, one must specify the additional
+ <literal>recordIdNumber</literal> parameter, which must be an
+ existing Zebra internal system ID number. When retrieving existing
+ records, the ID number is returned in the field
+ <literal>/*/id:idzebra/localnumber</literal> in the namespace
+ <literal>xmlns:id="http://www.indexdata.dk/zebra/"</literal>,
+ where it can be picked up for later record updates or deletes.
+ </para>
+ </sect1>
+
+
+ <sect1 id="gfs-config">
+ <title>YAZ Frontend Virtual Hosts</title>
+ <para>
+ <command>zebrasrv</command> uses the YAZ server frontend and does
+ support multiple virtual servers behind multiple listening sockets.
+ </para>
+ &zebrasrv-virtual;
+
+ <para>
+ Section "Virtual Hosts" in the YAZ manual.
+ <filename>http://www.indexdata.dk/yaz/doc/server.vhosts.tkl</filename>
+ </para>
+ </sect1>
+
+
+ <sect1 id="administration-cql-to-pqf">
+ <title>Server Side CQL to PQF Query Translation</title>
+ <para>
+ Using the
+ <literal><cql2rpn>l2rpn.txt</cql2rpn></literal>
+ YAZ Frontend Virtual
+ Hosts option, one can configure
+ the YAZ Frontend CQL-to-PQF
+ converter, specifying the interpretation of various
+ <ulink url="http://www.loc.gov/standards/sru/cql/">CQL</ulink>
+ indexes, relations, etc. in terms of Type-1 query attributes.
+ <!-- The yaz-client config file -->
+ </para>
+ <para>
+ For example, using server-side CQL-to-PQF conversion, one might
+ query a zebra server like this:
+ <screen>
+ <![CDATA[
+ yaz-client localhost:9999
+ Z> querytype cql
+ Z> find text=(plant and soil)
+ ]]>
+ </screen>
+ and - if properly configured - even static relevance ranking can
+ be performed using CQL query syntax:
+ <screen>
+ <![CDATA[
+ Z> find text = /relevant (plant and soil)
+ ]]>
+ </screen>
+ </para>
+
+ <para>
+ By the way, the same configuration can be used to
+ search using client-side CQL-to-PQF conversion:
+ (the only difference is <literal>querytype cql2rpn</literal>
+ instead of
+ <literal>querytype cql</literal>, and the call specifying a local
+ conversion file)
+ <screen>
+ <![CDATA[
+ yaz-client -q local/cql2pqf.txt localhost:9999
+ Z> querytype cql2rpn
+ Z> find text=(plant and soil)
+ ]]>
+ </screen>
+ </para>
+
+ <para>
+ Exhaustive information can be found in the
+ Section "Specification of CQL to RPN mappings" in the YAZ manual.
+ <ulink url="http://www.indexdata.dk/yaz/doc/tools.tkl#tools.cql.map">
+ http://www.indexdata.dk/yaz/doc/tools.tkl#tools.cql.map</ulink>,
+ and shall therefore not be repeated here.
+ </para>
+ <!--
+ <para>
+ See
+ <ulink url="http://www.loc.gov/z3950/agency/zing/cql/dc-indexes.html">
+ http://www.loc.gov/z3950/agency/zing/cql/dc-indexes.html</ulink>
+ for the Maintenance Agency's work-in-progress mapping of Dublin Core
+ indexes to Attribute Architecture (util, XD and BIB-2)
+ attributes.
+ </para>
+ -->
+ </sect1>
+
+
</chapter>
+
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