(Crosspost Handling): Move vindex to gnus-nov-is-evil to the Slow/Expensive

 Connection node.
(Slow/Expensive Connection): Describe not only NNTP connection; improve
 gnus-nov-is-evil; add an explanation of NOV.

diff --git a/texi/ChangeLog b/texi/ChangeLog
index ec71ca7..244d386 100644 (file)
--- a/texi/ChangeLog
+++ b/texi/ChangeLog
@@ -1,3 +1,10 @@
+2007-09-14  Katsumi Yamaoka  <yamaoka@jpl.org>
+
+       * gnus.texi (Crosspost Handling): Move vindex to gnus-nov-is-evil to
+       the Slow/Expensive Connection node.
+       (Slow/Expensive Connection): Describe not only NNTP connection; improve
+       gnus-nov-is-evil; add an explanation of NOV.
+
 2007-09-13  Katsumi Yamaoka  <yamaoka@jpl.org>
 
        * gnus.texi (Selecting a Group): Rename gnus-maximum-newsgroup to

diff --git a/texi/gnus.texi b/texi/gnus.texi
index 83ac297..49aa873 100644 (file)
--- a/texi/gnus.texi
+++ b/texi/gnus.texi
@@ -11052,7 +11052,6 @@ get does not read @samp{Xref:full}, then you should shout and whine at
 your news admin until she includes the @code{Xref} header in the
 overview files.
 
-@vindex gnus-nov-is-evil
 If you want Gnus to get the @code{Xref}s right all the time, you have to
 set @code{gnus-nov-is-evil} to @code{t}, which slows things down
 considerably.
@@ -28254,11 +28253,11 @@ for some quite common situations.
 
 
 @node Slow/Expensive Connection
-@subsection Slow/Expensive NNTP Connection
+@subsection Slow/Expensive Connection
 
 If you run Emacs on a machine locally, and get your news from a machine
 over some very thin strings, you want to cut down on the amount of data
-Gnus has to get from the @acronym{NNTP} server.
+Gnus has to get from the server.
 
 @table @code
 
@@ -28270,11 +28269,47 @@ also have to set @code{gnus-check-new-newsgroups} and
 doesn't suddenly decide to fetch the active file anyway.
 
 @item gnus-nov-is-evil
-This one has to be @code{nil}.  If not, grabbing article headers from
-the @acronym{NNTP} server will not be very fast.  Not all @acronym{NNTP} servers
-support @sc{xover}; Gnus will detect this by itself.
+@vindex gnus-nov-is-evil
+This one has to be @emph{always} @code{nil} (which is the default).  If
+you need not to use @acronym{NOV} (see below) with the @code{nntp} back
+end for example (@pxref{Crosspost Handling}), set
+@code{nntp-nov-is-evil} to a non-@code{nil} value instead of setting
+this.  But you normally have no need to set @code{nntp-nov-is-evil}
+since Gnus by itself will detect whether the @acronym{NNTP} server
+supports @acronym{NOV}.  Anyway, grabbing article headers from the
+@acronym{NNTP} server will not be very fast if you tell Gnus not to use
+@acronym{NOV}.
+
+As the variables for the other back ends, there are
+@code{nndiary-nov-is-evil}, @code{nndir-nov-is-evil},
+@code{nnfolder-nov-is-evil}, @code{nnimap-nov-is-evil},
+@code{nnml-nov-is-evil}, @code{nnspool-nov-is-evil}, and
+@code{nnwarchive-nov-is-evil}.  Note that a non-@code{nil} value for
+@code{gnus-nov-is-evil} overrides all those variables.
 @end table
 
+@noindent
+What's @acronym{NOV}?
+
+@acronym{NOV} stands for News OverView, which provide data containing
+the condensed header information of articles.  They are what the server
+makes; in the @code{nntp} back end Gnus uses the ones that the
+@acronym{NNTP} server makes, but Gnus makes them by itself in the server
+like @code{nnml} which Gnus performs.  The @acronym{NOV} data consist of
+one or more text lines (@pxref{Text Lines, ,Motion by Text Lines, elisp,
+The Emacs Lisp Reference Manual}) where each line has the header
+information of one article.  The header information is a tab-separated
+series of the header's contents including an article number, a subject,
+an author, a date, a message-id, references, etc.
+
+Those data enable Gnus to generate summary lines fast.  However, if the
+server does not support @acronym{NOV} or you disable it purposely or for
+some reason, Gnus will try to generate the header information by parsing
+article's header one by one.  It will take time.  Therefore, it is not
+usually a good idea to set @code{*-nov-is-evil} to a non-@code{nil}
+value unless there is such a reason that the server makes wrong
+@acronym{NOV} data.
+
 
 @node Slow Terminal Connection
 @subsection Slow Terminal Connection