-<chapter id="introduction">
- <!-- $Id: introduction.xml,v 1.6 2002-08-02 19:26:55 adam Exp $ -->
+ <chapter id="introduction">
<title>Introduction</title>
-
- <sect1>
- <title>Overview</title>
-
- <para>
- The
- <ulink url="http://www.indexdata.dk/zebra/">
- Zebra</ulink>
- system is a fielded free-text indexing and retrieval engine with a
- Z39.50 front-end. You can use our various toolkits or any commercial
- or free-ware Z39.50 client to access data stored in Zebra.
- </para>
-
- <para>
- FIXME - not a "first step" but a part of a complete system! -H
- </para>
-
- <para>
- The Zebra server is our first step towards the development of a fully
- configurable, open information system. Eventually, it will be paired
- off with a powerful Z39.50 client to support complex information
- management tasks within almost any application domain. We're making
- the server available now because it's no fun to be in the open
- information retrieval business all by yourself. We want to allow
- people with interesting data to make their things
- available in interesting ways, without having to start out
- by implementing yet another protocol stack from scratch.
- </para>
-
- <para>
- This document is an introduction to the Zebra system. It will tell you
- how to compile the software, and how to prepare your first database.
- It also explains how the server can be configured to give you the
- functionality that you need.
- </para>
-
- <para>
-
- If you find the software interesting, you should visit the
- <ulink url="http://www.indexdata.dk/zebra/">
- Zebra web site</ulink>, where you can join the
- <ulink url="http://www.indexdata.dk/mailman/listinfo/zebralist">
- mailing-list</ulink>
- by sending email to
- </para>
-
- </sect1>
-
- <sect1 id="features">
- <title>Features</title>
-
- <para>
- This is a list of some of the most important features of the
- system.
- </para>
-
- <para>
- <itemizedlist>
-
- <listitem>
- <para>
- Supports large databases - files for indices, etc. can be
- automatically partitioned over multiple disks.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Supports arbitrarily complex records - base input format is an
- SGML-like syntax which allows nested (structured) data elements, as
- well as variant forms of data.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Robust updating - records can be added and deleted without
- rebuilding the index from scratch.
- The update procedure is tolerant to crashes or hard interrupts
- during register updating - registers can be reconstructed following
- a crash.
- Registers can be safely updated even while users are accessing
- the server.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Supports random storage formats. A system of input filters driven by
- regular expressions allows you to easily process most ASCII-based
- data formats. SGML, XML, ISO2709 (MARC), and raw text are also
- supported.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Supports boolean queries as well as relevance-ranking (free-text)
- searching. Right truncation and masking in terms are supported, as
- well as full regular expressions.
- </para>
- </listitem>
-
- <listitem>
+
+ <section id="overview">
+ <title>Overview</title>
+ <para>
+ &zebra; is a free, fast, friendly information management system. It can
+ index records in &acro.xml;/&acro.sgml;, &acro.marc;, e-mail archives and many other
+ formats, and quickly find them using a combination of boolean
+ searching and relevance ranking. Search-and-retrieve applications can
+ be written using &acro.api;s in a wide variety of languages, communicating
+ with the &zebra; server using industry-standard information-retrieval
+ protocols or web services.
+ </para>
+ <para>
+ &zebra; is licensed Open Source, and can be
+ deployed by anyone for any purpose without license fees. The C source
+ code is open to anybody to read and change under the GPL license.
+ </para>
+ <para>
+ &zebra; is a networked component which acts as a
+ reliable &acro.z3950; server
+ for both record/document search, presentation, insert, update and
+ delete operations. In addition, it understands the &acro.sru; family of
+ webservices, which exist in &acro.rest; &acro.get;/&acro.post; and truly
+ &acro.soap; flavors.
+ </para>
+ <para>
+ &zebra; is available as MS Windows 2003 Server (32 bit) self-extracting
+ package as well as GNU/Debian Linux (32 bit and 64 bit) precompiled
+ packages. It has been deployed successfully on other Unix systems,
+ including Sun Sparc, HP Unix, and many variants of Linux and BSD
+ based systems.
+ </para>
+ <para>
+ <ulink url="http://www.indexdata.com/zebra/">http://www.indexdata.com/zebra/</ulink>
+ <ulink url="http://ftp.indexdata.dk/pub/zebra/win32/">http://ftp.indexdata.dk/pub/zebra/win32/</ulink>
+ <ulink url="http://ftp.indexdata.dk/pub/zebra/debian/">http://ftp.indexdata.dk/pub/zebra/debian/</ulink>
+ </para>
+
+ <para>
+ <ulink url="http://indexdata.dk/zebra/">&zebra;</ulink>
+ is a high-performance, general-purpose structured text
+ indexing and retrieval engine. It reads records in a
+ variety of input formats (e.g. email, &acro.xml;, &acro.marc;) and provides access
+ to them through a powerful combination of boolean search
+ expressions and relevance-ranked free-text queries.
+ </para>
+
+ <para>
+ &zebra; supports large databases (tens of millions of records,
+ tens of gigabytes of data). It allows safe, incremental
+ database updates on live systems. Because &zebra; supports
+ the industry-standard information retrieval protocol, &acro.z3950;,
+ you can search &zebra; databases using an enormous variety of
+ programs and toolkits, both commercial and free, which understand
+ this protocol. Application libraries are available to allow
+ bespoke clients to be written in Perl, C, C++, Java, Tcl, Visual
+ Basic, Python, &acro.php; and more - see the
+ <ulink url="&url.zoom;">&acro.zoom; web site</ulink>
+ for more information on some of these client toolkits.
+ </para>
+
+ <para>
+ This document is an introduction to the &zebra; system. It explains
+ how to compile the software, how to prepare your first database,
+ and how to configure the server to give you the
+ functionality that you need.
+ </para>
+ </section>
+
+ <section id="features">
+ <title>&zebra; Features Overview</title>
+
+ <section id="features-document">
+ <title>&zebra; Document Model</title>
+
+ <table id="table-features-document" frame="top">
+ <title>&zebra; document model</title>
+ <tgroup cols="4">
+ <colspec colwidth="1*" colname="feature"/>
+ <colspec colwidth="1*" colname="availability"/>
+ <colspec colwidth="3*" colname="notes"/>
+ <colspec colwidth="2*" colname="references"/>
+ <thead>
+ <row>
+ <entry>Feature</entry>
+ <entry>Availability</entry>
+ <entry>Notes</entry>
+ <entry>Reference</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Complex semi-structured Documents</entry>
+ <entry>&acro.xml; and &acro.grs1; Documents</entry>
+ <entry>Both &acro.xml; and &acro.grs1; documents exhibit a &acro.dom; like internal
+ representation allowing for complex indexing and display rules</entry>
+ <entry><xref linkend="record-model-alvisxslt"/> and
+ <xref linkend="grs"/></entry>
+ </row>
+ <row>
+ <entry>Input document formats</entry>
+ <entry>&acro.xml;, &acro.sgml;, Text, ISO2709 (&acro.marc;)</entry>
+ <entry>
+ A system of input filters driven by
+ regular expressions allows most ASCII-based
+ data formats to be easily processed.
+ &acro.sgml;, &acro.xml;, ISO2709 (&acro.marc;), and raw text are also
+ supported.</entry>
+ <entry><xref linkend="componentmodules"/></entry>
+ </row>
+ <row>
+ <entry>Document storage</entry>
+ <entry>Index-only, Key storage, Document storage</entry>
+ <entry>Data can be, and usually is, imported
+ into &zebra;'s own storage, but &zebra; can also refer to
+ external files, building and maintaining indexes of "live"
+ collections.</entry>
+ <entry></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+
+ <section id="features-search">
+ <title>&zebra; Search Features</title>
+
+ <table id="table-features-search" frame="top">
+ <title>&zebra; search functionality</title>
+ <tgroup cols="4">
+ <colspec colwidth="1*" colname="feature"/>
+ <colspec colwidth="1*" colname="availability"/>
+ <colspec colwidth="3*" colname="notes"/>
+ <colspec colwidth="2*" colname="references"/>
+ <thead>
+ <row>
+ <entry>Feature</entry>
+ <entry>Availability</entry>
+ <entry>Notes</entry>
+ <entry>Reference</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Query languages</entry>
+ <entry>&acro.cql; and &acro.rpn;/&acro.pqf;</entry>
+ <entry>The type-1 Reverse Polish Notation (&acro.rpn;)
+ and its textual representation Prefix Query Format (&acro.pqf;) are
+ supported. The Common Query Language (&acro.cql;) can be configured as
+ a mapping from &acro.cql; to &acro.rpn;/&acro.pqf;</entry>
+ <entry><xref linkend="querymodel-query-languages-pqf"/> and
+ <xref linkend="querymodel-cql-to-pqf"/></entry>
+ </row>
+ <row>
+ <entry>Complex boolean query tree</entry>
+ <entry>&acro.cql; and &acro.rpn;/&acro.pqf;</entry>
+ <entry>Both &acro.cql; and &acro.rpn;/&acro.pqf; allow atomic query parts (&acro.apt;) to
+ be combined into complex boolean query trees</entry>
+ <entry><xref linkend="querymodel-rpn-tree"/></entry>
+ </row>
+ <row>
+ <entry>Field search</entry>
+ <entry>user defined</entry>
+ <entry>Atomic query parts (&acro.apt;) are either general, or
+ directed at user-specified document fields
+ </entry>
+ <entry><xref linkend="querymodel-atomic-queries"/>,
+ <xref linkend="querymodel-use-string"/>,
+ <xref linkend="querymodel-bib1-use"/>, and
+ <xref linkend="querymodel-idxpath-use"/></entry>
+ </row>
+ <row>
+ <entry>Data normalization</entry>
+ <entry>user defined</entry>
+ <entry>Data normalization, text tokenization and character
+ mappings can be applied during indexing and searching</entry>
+ <entry><xref linkend="fields-and-charsets"/></entry>
+ </row>
+ <row>
+ <entry>Predefined field types</entry>
+ <entry>user defined</entry>
+ <entry>Data fields can be indexed as phrase, as into word
+ tokenized text, as numeric values, URLs, dates, and raw binary
+ data.</entry>
+ <entry><xref linkend="character-map-files"/> and
+ <xref linkend="querymodel-pqf-apt-mapping-structuretype"/>
+ </entry>
+ </row>
+ <row>
+ <entry>Regular expression matching</entry>
+ <entry>available</entry>
+ <entry>Full regular expression matching and "approximate
+ matching" (e.g. spelling mistake corrections) are handled.</entry>
+ <entry><xref linkend="querymodel-regular"/></entry>
+ </row>
+ <row>
+ <entry>Term truncation</entry>
+ <entry>left, right, left-and-right</entry>
+ <entry>The truncation attribute specifies whether variations of
+ one or more characters are allowed between search term and hit
+ terms, or not. Using non-default truncation attributes will
+ broaden the document hit set of a search query.</entry>
+ <entry><xref linkend="querymodel-bib1-truncation"/></entry>
+ </row>
+ <row>
+ <entry>Fuzzy searches</entry>
+ <entry>Spelling correction</entry>
+ <entry>In addition, fuzzy searches are implemented, where one
+ spelling mistake in search terms is matched</entry>
+ <entry><xref linkend="querymodel-bib1-truncation"/></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+
+ <section id="features-scan">
+ <title>&zebra; Index Scanning</title>
+
+ <table id="table-features-scan" frame="top">
+ <title>&zebra; index scanning</title>
+ <tgroup cols="4">
+ <colspec colwidth="1*" colname="feature"/>
+ <colspec colwidth="1*" colname="availability"/>
+ <colspec colwidth="3*" colname="notes"/>
+ <colspec colwidth="2*" colname="references"/>
+ <thead>
+ <row>
+ <entry>Feature</entry>
+ <entry>Availability</entry>
+ <entry>Notes</entry>
+ <entry>Reference</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Scan</entry>
+ <entry>term suggestions</entry>
+ <entry><literal>Scan</literal> on a given named index returns all the
+ indexed terms in lexicographical order near the given start
+ term. This can be used to create drop-down menus and search
+ suggestions.</entry>
+ <entry><xref linkend="querymodel-operation-type-scan"/> and
+ <xref linkend="querymodel-atomic-queries"/>
+ </entry>
+ </row>
+ <row>
+ <entry>Facetted browsing</entry>
+ <entry>available</entry>
+ <entry>Zebra 2.1 and allows retrieval of facets for
+ a result set.
+ </entry>
+ <entry><xref linkend="querymodel-zebra-attr-scan"/></entry>
+ </row>
+ <row>
+ <entry>Drill-down or refine-search</entry>
+ <entry>partially</entry>
+ <entry>scanning in result sets can be used to implement
+ drill-down in search clients</entry>
+ <entry><xref linkend="querymodel-zebra-attr-scan"/></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+
+ <section id="features-presentation">
+ <title>&zebra; Document Presentation</title>
+
+ <table id="table-features-presentation" frame="top">
+ <title>&zebra; document presentation</title>
+ <tgroup cols="4">
+ <colspec colwidth="1*" colname="feature"/>
+ <colspec colwidth="1*" colname="availability"/>
+ <colspec colwidth="3*" colname="notes"/>
+ <colspec colwidth="2*" colname="references"/>
+ <thead>
+ <row>
+ <entry>Feature</entry>
+ <entry>Availability</entry>
+ <entry>Notes</entry>
+ <entry>Reference</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Hit count</entry>
+ <entry>yes</entry>
+ <entry>Search results include at any time the total hit count of a given
+ query, either exact computed, or approximative, in case that the
+ hit count exceeds a possible pre-defined hit set truncation
+ level.</entry>
+ <entry>
+ <xref linkend="querymodel-zebra-local-attr-limit"/> and
+ <xref linkend="zebra-cfg"/>
+ </entry>
+ </row>
+ <row>
+ <entry>Paged result sets</entry>
+ <entry>yes</entry>
+ <entry>Paging of search requests and present/display request
+ can return any successive number of records from any start
+ position in the hit set, i.e. it is trivial to provide search
+ results in successive pages of any size.</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>&acro.xml; document transformations</entry>
+ <entry>&acro.xslt; based</entry>
+ <entry> Record presentation can be performed in many
+ pre-defined &acro.xml; data
+ formats, where the original &acro.xml; records are on-the-fly transformed
+ through any preconfigured &acro.xslt; transformation. It is therefore
+ trivial to present records in short/full &acro.xml; views, transforming to
+ RSS, Dublin Core, or other &acro.xml; based data formats, or transform
+ records to XHTML snippets ready for inserting in XHTML pages.</entry>
+ <entry>
+ <xref linkend="record-model-alvisxslt-elementset"/></entry>
+ </row>
+ <row>
+ <entry>Binary record transformations</entry>
+ <entry>&acro.marc;, &acro.usmarc;, &acro.marc21; and &acro.marcxml;</entry>
+ <entry>post-filter record transformations</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>Record Syntaxes</entry>
+ <entry></entry>
+ <entry> Multiple record syntaxes
+ for data retrieval: &acro.grs1;, &acro.sutrs;,
+ &acro.xml;, ISO2709 (&acro.marc;), etc. Records can be mapped between
+ record syntaxes and schemas on the fly.</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>&zebra; internal metadata</entry>
+ <entry>yes</entry>
+ <entry> &zebra; internal document metadata can be fetched in
+ &acro.sutrs; and &acro.xml; record syntaxes. Those are useful in client
+ applications.</entry>
+ <entry><xref linkend="special-retrieval"/></entry>
+ </row>
+ <row>
+ <entry>&zebra; internal raw record data</entry>
+ <entry>yes</entry>
+ <entry> &zebra; internal raw, binary record data can be fetched in
+ &acro.sutrs; and &acro.xml; record syntaxes, leveraging %zebra; to a
+ binary storage system</entry>
+ <entry><xref linkend="special-retrieval"/></entry>
+ </row>
+ <row>
+ <entry>&zebra; internal record field data</entry>
+ <entry>yes</entry>
+ <entry> &zebra; internal record field data can be fetched in
+ &acro.sutrs; and &acro.xml; record syntaxes. This makes very fast minimal
+ record data displays possible.</entry>
+ <entry><xref linkend="special-retrieval"/></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+
+ <section id="features-sort-rank">
+ <title>&zebra; Sorting and Ranking</title>
+
+ <table id="table-features-sort-rank" frame="top">
+ <title>&zebra; sorting and ranking</title>
+ <tgroup cols="4">
+ <colspec colwidth="1*" colname="feature"/>
+ <colspec colwidth="1*" colname="availability"/>
+ <colspec colwidth="3*" colname="notes"/>
+ <colspec colwidth="2*" colname="references"/>
+ <thead>
+ <row>
+ <entry>Feature</entry>
+ <entry>Availability</entry>
+ <entry>Notes</entry>
+ <entry>Reference</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Sort</entry>
+ <entry>numeric, lexicographic</entry>
+ <entry>Sorting on the basis of alpha-numeric and numeric data
+ is supported. Alphanumeric sorts can be configured for
+ different data encodings and locales for European languages.</entry>
+ <entry><xref linkend="administration-ranking-sorting"/> and
+ <xref linkend="querymodel-zebra-attr-sorting"/></entry>
+ </row>
+ <row>
+ <entry>Combined sorting</entry>
+ <entry>yes</entry>
+ <entry>Sorting on the basis of combined sorts e.g. combinations of
+ ascending/descending sorts of lexicographical/numeric/date field data
+ is supported</entry>
+ <entry><xref linkend="administration-ranking-sorting"/></entry>
+ </row>
+ <row>
+ <entry>Relevance ranking</entry>
+ <entry>TF-IDF like</entry>
+ <entry>Relevance-ranking of free-text queries is supported
+ using a TF-IDF like algorithm.</entry>
+ <entry><xref linkend="administration-ranking-dynamic"/></entry>
+ </row>
+ <row>
+ <entry>Static pre-ranking</entry>
+ <entry>yes</entry>
+ <entry>Enables pre-index time ranking of documents where hit
+ lists are ordered first by ascending static rank, then by
+ ascending document ID.</entry>
+ <entry><xref linkend="administration-ranking-static"/></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+
+
+ <section id="features-updates">
+ <title>&zebra; Live Updates</title>
+
+
+ <table id="table-features-updates" frame="top">
+ <title>&zebra; live updates</title>
+ <tgroup cols="4">
+ <colspec colwidth="1*" colname="feature"/>
+ <colspec colwidth="1*" colname="availability"/>
+ <colspec colwidth="3*" colname="notes"/>
+ <colspec colwidth="2*" colname="references"/>
+ <thead>
+ <row>
+ <entry>Feature</entry>
+ <entry>Availability</entry>
+ <entry>Notes</entry>
+ <entry>Reference</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Incremental and batch updates</entry>
+ <entry></entry>
+ <entry>It is possible to schedule record inserts/updates/deletes in any
+ quantity, from single individual handled records to batch updates
+ in strikes of any size, as well as total re-indexing of all records
+ from file system. </entry>
+ <entry><xref linkend="zebraidx"/></entry>
+ </row>
+ <row>
+ <entry>Remote updates</entry>
+ <entry>&acro.z3950; extended services</entry>
+ <entry>Updates can be performed from remote locations using the
+ &acro.z3950; extended services. Access to extended services can be
+ login-password protected.</entry>
+ <entry><xref linkend="administration-extended-services"/> and
+ <xref linkend="zebra-cfg"/></entry>
+ </row>
+ <row>
+ <entry>Live updates</entry>
+ <entry>transaction based</entry>
+ <entry> Data updates are transaction based and can be performed
+ on running &zebra; systems. Full searchability is preserved
+ during life data update due to use of shadow disk areas for
+ update operations. Multiple update transactions at the same
+ time are lined up, to be performed one after each other. Data
+ integrity is preserved.</entry>
+ <entry><xref linkend="shadow-registers"/></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+
+ <section id="features-protocol">
+ <title>&zebra; Networked Protocols</title>
+
+ <table id="table-features-protocol" frame="top">
+ <title>&zebra; networked protocols</title>
+ <tgroup cols="4">
+ <colspec colwidth="1*" colname="feature"/>
+ <colspec colwidth="1*" colname="availability"/>
+ <colspec colwidth="3*" colname="notes"/>
+ <colspec colwidth="2*" colname="references"/>
+ <thead>
+ <row>
+ <entry>Feature</entry>
+ <entry>Availability</entry>
+ <entry>Notes</entry>
+ <entry>Reference</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Fundamental operations</entry>
+ <entry>&acro.z3950;/&acro.sru; <literal>explain</literal>,
+ <literal>search</literal>, <literal>scan</literal>, and
+ <literal>update</literal></entry>
+ <entry></entry>
+ <entry><xref linkend="querymodel-operation-types"/></entry>
+ </row>
+ <row>
+ <entry>&acro.z3950; protocol support</entry>
+ <entry>yes</entry>
+ <entry> Protocol facilities supported are:
+ <literal>init</literal>, <literal>search</literal>,
+ <literal>present</literal> (retrieval),
+ Segmentation (support for very large records),
+ <literal>delete</literal>, <literal>scan</literal>
+ (index browsing), <literal>sort</literal>,
+ <literal>close</literal> and support for the <literal>update</literal>
+ Extended Service to add or replace an existing &acro.xml;
+ record. Piggy-backed presents are honored in the search
+ request. Named result sets are supported.</entry>
+ <entry><xref linkend="protocol-support"/></entry>
+ </row>
+ <row>
+ <entry>Web Service support</entry>
+ <entry>&acro.sru;</entry>
+ <entry> The protocol operations <literal>explain</literal>,
+ <literal>searchRetrieve</literal> and <literal>scan</literal>
+ are supported. <ulink url="&url.cql;">&acro.cql;</ulink> to internal
+ query model &acro.rpn;
+ conversion is supported. Extended RPN queries
+ for search/retrieve and scan are supported.</entry>
+ <entry><xref linkend="zebrasrv-sru-support"/></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+
+ <section id="features-scalability">
+ <title>&zebra; Data Size and Scalability</title>
+
+ <table id="table-features-scalability" frame="top">
+ <title>&zebra; data size and scalability</title>
+ <tgroup cols="4">
+ <colspec colwidth="1*" colname="feature"/>
+ <colspec colwidth="1*" colname="availability"/>
+ <colspec colwidth="3*" colname="notes"/>
+ <colspec colwidth="2*" colname="references"/>
+ <thead>
+ <row>
+ <entry>Feature</entry>
+ <entry>Availability</entry>
+ <entry>Notes</entry>
+ <entry>Reference</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>No of records</entry>
+ <entry>40-60 million</entry>
+ <entry></entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>Data size</entry>
+ <entry>100 GB of record data</entry>
+ <entry>&zebra; based applications have successfully indexed up
+ to 100 GB of record data</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>Scale out</entry>
+ <entry>multiple discs</entry>
+ <entry></entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>Performance</entry>
+ <entry><literal>O(n * log N)</literal></entry>
+ <entry> &zebra; query speed and performance is affected roughly by
+ <literal>O(log N)</literal>,
+ where <literal>N</literal> is the total database size, and by
+ <literal>O(n)</literal>, where <literal>n</literal> is the
+ specific query hit set size.</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>Average search times</entry>
+ <entry></entry>
+ <entry> Even on very large size databases hit rates of 20 queries per
+ seconds with average query answering time of 1 second are possible,
+ provided that the boolean queries are constructed sufficiently
+ precise to result in hit sets of the order of 1000 to 5.000
+ documents.</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>Large databases</entry>
+ <entry>64 bit file pointers</entry>
+ <entry>64 file pointers assure that register files can extend
+ the 2 GB limit. Logical files can be
+ automatically partitioned over multiple disks, thus allowing for
+ large databases.</entry>
+ <entry></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+
+ <section id="features-platforms">
+ <title>&zebra; Supported Platforms</title>
+
+ <table id="table-features-platforms" frame="top">
+ <title>&zebra; supported platforms</title>
+ <tgroup cols="4">
+ <colspec colwidth="1*" colname="feature"/>
+ <colspec colwidth="1*" colname="availability"/>
+ <colspec colwidth="3*" colname="notes"/>
+ <colspec colwidth="2*" colname="references"/>
+ <thead>
+ <row>
+ <entry>Feature</entry>
+ <entry>Availability</entry>
+ <entry>Notes</entry>
+ <entry>Reference</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Linux</entry>
+ <entry></entry>
+ <entry>GNU Linux (32 and 64bit), journaling Reiser or (better)
+ JFS file system
+ on disks. NFS file systems are not supported.
+ GNU/Debian Linux packages are available</entry>
+ <entry><xref linkend="installation-debian"/></entry>
+ </row>
+ <row>
+ <entry>Unix</entry>
+ <entry>tar-ball</entry>
+ <entry>&zebra; is written in portable C, so it runs on most
+ Unix-like systems.
+ Usual tar-ball install possible on many major Unix systems</entry>
+ <entry><xref linkend="installation-unix"/></entry>
+ </row>
+ <row>
+ <entry>Windows</entry>
+ <entry>NT/2000/2003/XP</entry>
+ <entry>&zebra; runs as well on Windows (NT/2000/2003/XP).
+ Windows installer packages available</entry>
+ <entry><xref linkend="installation-win32"/></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+
+
+ </section>
+
+ <section id="introduction-apps">
+ <title>References and &zebra; based Applications</title>
+ <para>
+ &zebra; has been deployed in numerous applications, in both the
+ academic and commercial worlds, in application domains as diverse
+ as bibliographic catalogues, Geo-spatial information, structured
+ vocabulary browsing, government information locators, civic
+ information systems, environmental observations, museum information
+ and web indexes.
+ </para>
+ <para>
+ Notable applications include the following:
+ </para>
+
+
+ <section id="koha-ils">
+ <title>Koha free open-source ILS</title>
+ <para>
+ <ulink url="http://www.koha.org/">Koha</ulink> is a full-featured
+ open-source ILS, initially developed in
+ New Zealand by Katipo Communications Ltd, and first deployed in
+ January of 2000 for Horowhenua Library Trust. It is currently
+ maintained by a team of software providers and library technology
+ staff from around the globe.
+ </para>
+ <para>
+ <ulink url="http://liblime.com/">LibLime</ulink>,
+ a company that is marketing and supporting Koha, adds in
+ the new release of Koha 3.0 the &zebra;
+ database server to drive its bibliographic database.
+ </para>
+ <para>
+ In early 2005, the Koha project development team began looking at
+ ways to improve &acro.marc; support and overcome scalability limitations
+ in the Koha 2.x series. After extensive evaluations of the best
+ of the Open Source textual database engines - including MySQL
+ full-text searching, PostgreSQL, Lucene and Plucene - the team
+ selected &zebra;.
+ </para>
+ <para>
+ "&zebra; completely eliminates scalability limitations, because it
+ can support tens of millions of records." explained Joshua
+ Ferraro, LibLime's Technology President and Koha's Project
+ Release Manager. "Our performance tests showed search results in
+ under a second for databases with over 5 million records on a
+ modest i386 900Mhz test server."
+ </para>
+ <para>
+ "&zebra; also includes support for true boolean search expressions
+ and relevance-ranked free-text queries, both of which the Koha
+ 2.x series lack. &zebra; also supports incremental and safe
+ database updates, which allow on-the-fly record
+ management. Finally, since &zebra; has at its heart the &acro.z3950;
+ protocol, it greatly improves Koha's support for that critical
+ library standard."
+ </para>
+ <para>
+ Although the bibliographic database will be moved to &zebra;, Koha
+ 3.0 will continue to use a relational SQL-based database design
+ for the 'factual' database. "Relational database managers have
+ their strengths, in spite of their inability to handle large
+ numbers of bibliographic records efficiently," summed up Ferraro,
+ "We're taking the best from both worlds in our redesigned Koha
+ 3.0.
+ </para>
+ <para>
+ See also LibLime's newsletter article
+ <ulink url="http://www.liblime.com/newsletter/2006/01/features/koha-earns-its-stripes/">
+ Koha Earns its Stripes</ulink>.
+ </para>
+ </section>
+
+
+ <section id="kete-dom">
+ <title>Kete Open Source Digital Library and Archiving software</title>
+ <para>
+ <ulink url="http://kete.net.nz/">Kete</ulink> is a digital object
+ management repository, initially developed in
+ New Zealand. Initial development has
+ been a partnership between the Horowhenua Library Trust and
+ Katipo Communications Ltd. funded as part of the Community
+ Partnership Fund in 2006.
+ Kete is purpose built
+ software to enable communities to build their own digital
+ libraries, archives and repositories.
+ </para>
+ <para>
+ It is based on Ruby-on-Rails and MySQL, and integrates the &zebra; server
+ and the &yaz; toolkit for indexing and retrieval of it's content.
+ Zebra is run as separate computer process from the Kete
+ application.
+ See
+ how Kete <ulink
+ url="http://kete.net.nz/documentation/topics/show/139-managing-zebra">manages
+ Zebra.</ulink>
+ </para>
+ <para>
+ Why does Kete wants to use Zebra?? Speed, Scalability and easy
+ integration with Koha. Read their
+ <ulink
+ url="http://kete.net.nz/blog/topics/show/44-who-what-why-when-answering-some-of-the-niggly-development-questions">detailed
+ reasoning here.</ulink>
+ </para>
+ </section>
+
+ <section id="reindex-ils">
+ <title>ReIndex.Net web based ILS</title>
+ <para>
+ <ulink url="http://www.reindex.net/index.php?lang=en">Reindex.net</ulink>
+ is a netbased library service offering all
+ traditional functions on a very high level plus many new
+ services. Reindex.net is a comprehensive and powerful WEB system
+ based on standards such as &acro.xml; and &acro.z3950;.
+ updates. Reindex supports &acro.marc21;, dan&acro.marc; eller Dublin Core with
+ UTF8-encoding.
+ </para>
+ <para>
+ Reindex.net runs on GNU/Debian Linux with &zebra; and Simpleserver
+ from Index
+ Data for bibliographic data. The relational database system
+ Sybase 9 &acro.xml; is used for
+ administrative data.
+ Internally &acro.marcxml; is used for bibliographical records. Update
+ utilizes &acro.z3950; extended services.
+ </para>
+ </section>
+
+ <section id="dads-article-database">
+ <title>DADS - the DTV Article Database
+ Service</title>
+ <para>
+ DADS is a huge database of more than ten million records, totalling
+ over ten gigabytes of data. The records are metadata about academic
+ journal articles, primarily scientific; about 10% of these
+ metadata records link to the full text of the articles they
+ describe, a body of about a terabyte of information (although the
+ full text is not indexed.)
+ </para>
+ <para>
+ It allows students and researchers at DTU (Danmarks Tekniske
+ Universitet, the Technical College of Denmark) to find and order
+ articles from multiple databases in a single query. The database
+ contains literature on all engineering subjects. It's available
+ on-line through a web gateway, though currently only to registered
+ users.
+ </para>
+ <para>
+ More information can be found at
+ <ulink url="http://www.dtic.dtu.dk/"/> and
+ <ulink url="http://dads.dtv.dk"/>
+ </para>
+ </section>
+
+ <section id="uls">
+ <title>ULS (Union List of Serials)</title>
+ <para>
+ The M25 Systems Team
+ has created a union catalogue for the periodicals of the
+ twenty-one constituent libraries of the University of London and
+ the University of Westminster
+ (<ulink url="http://www.m25lib.ac.uk/ULS/"/>).
+ They have achieved this using an
+ unusual architecture, which they describe as a
+ ``non-distributed virtual union catalogue''.
+ </para>
+ <para>
+ The member libraries send in data files representing their
+ periodicals, including both brief bibliographic data and summary
+ holdings. Then 21 individual &acro.z3950; targets are created, each
+ using &zebra;, and all mounted on the single hardware server.
+ The live service provides a web gateway allowing &acro.z3950; searching
+ of all of the targets or a selection of them. &zebra;'s small
+ footprint allows a relatively modest system to comfortably host
+ the 21 servers.
+ </para>
+ <para>
+ More information can be found at
+ <ulink url="http://www.m25lib.ac.uk/ULS/"/>
+ </para>
+ </section>
+
+ <section id="various-web-indexes">
+ <title>Various web indexes</title>
+ <para>
+ &zebra; has been used by a variety of institutions to construct
+ indexes of large web sites, typically in the region of tens of
+ millions of pages. In this role, it functions somewhat similarly
+ to the engine of Google or AltaVista, but for a selected intranet
+ or a subset of the whole Web.
+ </para>
+ <para>
+ For example, Liverpool University's web-search facility (see on
+ the home page at
+ <ulink url="http://www.liv.ac.uk/"/>
+ and many sub-pages) works by relevance-searching a &zebra; database
+ which is populated by the Harvest-NG web-crawling software.
+ </para>
+ <para>
+ For more information on Liverpool university's intranet search
+ architecture, contact John Gilbertson
+ <email>jgilbert@liverpool.ac.uk</email>
+ </para>
+ <para>
+ Kang-Jin Lee
+ has recently modified the Harvest web indexer to use &zebra; as
+ its native repository engine. His comments on the switch over
+ from the old engine are revealing:
+ <blockquote>
+ <para>
+ The first results after some testing with &zebra; are very
+ promising. The tests were done with around 220,000 SOIF files,
+ which occupies 1.6GB of disk space.
+ </para>
<para>
- Can import the data into Zebras own storage, or just refer to
- external files (html pages).
+ Building the index from scratch takes around one hour with &zebra;
+ where [old-engine] needs around five hours. While [old-engine]
+ blocks search requests when updating its index, &zebra; can still
+ answer search requests.
+ [...]
+ &zebra; supports incremental indexing which will speed up indexing
+ even further.
</para>
- </listitem>
-
- <listitem>
- <para>
- Supports multiple concrete syntaxes
- for record exchange (depending on the configuration): GRS-1, SUTRS,
- XML, ISO2709 (*MARC). Records can be mapped between record syntaxes
- and schema on the fly.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Supports approximate matching in registers (ie. spelling mistakes,
- etc).
- </para>
- </listitem>
-
- <listitem>
- <para>
- Zebra is written in portable C, so it runs on most Unix-like systems
- as well as Windows NT - a binary distribution for Windows NT is available.
- </para>
- </listitem>
-
- </itemizedlist>
-
- </para>
-
- <para>
- Protocol support:
- </para>
-
- <para>
- <itemizedlist>
- <listitem>
- <para>
- Protocol facilities: Init, Search, Retrieve, Delete, Browse and Sort.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Piggy-backed presents are honored in the search-request.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Named result sets are supported.
- </para>
- </listitem>
- <listitem>
- <para>
- Easily configured to support different application profiles, with
- tables for attribute sets, tag sets, and abstract syntaxes.
- Additional tables control facilities such as element mappings to
- different schema (eg., GILS-to-USMARC).
- </para>
- </listitem>
-
- <listitem>
- <para>
- Complex composition specifications using Espec-1 are partially
- supported (simple element requests only).
- </para>
- </listitem>
-
- <listitem>
- <para>
- Element Set Names are defined using the Espec-1 capability of the
- system, and are given in configuration files as simple element
- requests (and possibly variant requests).
- </para>
- </listitem>
-
- </itemizedlist>
-
- </para>
-
- </sect1>
-
- <sect1 id="future">
- <title>Future Work</title>
-
- <para>
- These are some of the plans that we have for the software in the near
- and far future, approximately ordered after their relative importance.
- Items marked with an
- asterisk will be implemented before the
- last beta release.
- FIXME - What are the current plans?
- </para>
-
- <para>
- <itemizedlist>
-
- <listitem>
- <para>
- *Finalize the data element <emphasis>include</emphasis> facility
- to support multimedia data elements in records.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Add more sophisticated relevance ranking mechanisms.
- Add support for soundex and stemming.
- Add relevance <emphasis>feedback</emphasis> support.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Complete EXPLAIN support.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Add support for very large records by implementing segmentation and/or
- variant pieces.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Support the Item Update extended service of the protocol.
- </para>
- </listitem>
-
- <listitem>
- <para>
- We want to add a management system that allows you to
- control your databases and configuration tables from a graphical
- interface.
- </para>
- </listitem>
- </itemizedlist>
- </para>
-
- <para>
- Programmers thrive on user feedback. If you are interested in a
- facility that you don't see mentioned here, or if there's something
- you think we could do better, please drop us a mail.
- If you think it's all really neat, you're welcome to drop us a line
- saying that, too. You'll find contact info at the end of this file.
- </para>
-
- </sect1>
-</chapter>
+ <para>
+ While the search time of [old-engine] varies from some seconds
+ to some minutes depending how expensive the query is, &zebra;
+ usually takes around one to three seconds, even for expensive
+ queries.
+ [...]
+ &zebra; can search more than 100 times faster than [old-engine]
+ and can process multiple search requests simultaneously
+ </para>
+ <para>
+ I am very happy to see such nice software available under GPL.
+ </para>
+ </blockquote>
+ </para>
+ </section>
+ </section>
+
+ <section id="introduction-support">
+ <title>Support</title>
+ <para>
+ You can get support for &zebra; from at least three sources.
+ </para>
+ <para>
+ First, there's the &zebra; web site at
+ <ulink url="&url.idzebra;"/>,
+ which always has the most recent version available for download.
+ If you have a problem with &zebra;, the first thing to do is see
+ whether it's fixed in the current release.
+ </para>
+ <para>
+ Second, there's the &zebra; mailing list. Its home page at
+ <ulink url="&url.idzebra.mailinglist;"/>
+ includes a complete archive of all messages that have ever been
+ posted on the list. The &zebra; mailing list is used both for
+ announcements from the authors (new
+ releases, bug fixes, etc.) and general discussion. You are welcome
+ to seek support there. Join by filling the form on the list home page.
+ </para>
+ </section>
+ </chapter>
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