doc for indexStoreDocText

src/doc/user/recoll.conf.xml

@@ -174,7 +174,7 @@ members. This is passed to the filters in the environment
 as RECOLL_FILTER_MAXMEMBERKB.</para></listitem></varlistentry>
 </variablelist></sect3>
 <sect3 id="RCL.INSTALL.CONFIG.RECOLLCONF.TERMS">
-<title>Parameters affecting how we generate terms </title><variablelist>
+<title>Parameters affecting how we generate terms and organize the index </title><variablelist>
 <varlistentry id="RCL.INSTALL.CONFIG.RECOLLCONF.INDEXSTRIPCHARS">
 <term><varname>indexStripChars</varname></term>
 <listitem><para>Decide if we store
@@ -184,6 +184,34 @@ will be bigger, and some marginal weirdness may sometimes occur. The
 default is a stripped index. When using multiple indexes for a search,
 this parameter must be defined identically for all. Changing the value
 implies an index reset.</para></listitem></varlistentry>
+<varlistentry id="RCL.INSTALL.CONFIG.RECOLLCONF.INDEXSTOREDOCTEXT">
+<term><varname>indexStoreDocText</varname></term>
+<listitem><para>Decide if we store the
+documents' text content in the index. Storing the text
+allows extracting snippets from it at query time, instead of building
+them from index position data.
+Newer Xapian index formats have rendered our use of positions list
+unacceptably slow in some cases. The last Xapian index format with good
+performance for the old method is Chert, which is default for 1.2, still
+supported but not default in 1.4 and will be dropped in 1.6.
+The stored document text is translated from its original format to UTF-8
+plain text, but not stripped of upper-case, diacritics, or punctuation
+signs. Storing it increases the index size by 10-20% typically, but also
+allows for nicer snippets, so it may be worth enabling it even if not
+strictly needed for performance if you can afford the space.
+The variable only has an effect when creating an index, meaning that the
+xapiandb directory must not exist yet. Its exact effect depends on the
+Xapian version.
+For Xapian 1.4, if the variable is set to 0, the Chert format will be
+used, and the text will not be stored. If the variable is 1, Glass will
+be used, and the text stored.
+For Xapian 1.2, and for versions after 1.5 and newer, the index format is
+always the default, but the variable controls if the text is stored or
+not, and the abstract generation method. With Xapian 1.5 and later, and
+the variable set to 0, abstract generation may be very slow, but this
+setting may still be useful to save space if you do not use abstract
+generation at all.
+</para></listitem></varlistentry>
 <varlistentry id="RCL.INSTALL.CONFIG.RECOLLCONF.NONUMBERS">
 <term><varname>nonumbers</varname></term>
 <listitem><para>Decides if terms will be