diff --git a/doc/rrdupdate.pod b/doc/rrdupdate.pod
index 797b8bd33a2e4112907939db55b7f1fb62bf0980..c285ee372545e02595607c12a3445d01ebe64916 100644 (file)
--- a/doc/rrdupdate.pod
+++ b/doc/rrdupdate.pod
=head1 SYNOPSIS
-B<rrdtool> {B<update> | B<updatev>} I<filename>
-S<[B<--template>|B<-t> I<ds-name>[B<:>I<ds-name>]...]>
-S<B<N>|I<timestamp>B<:>I<value>[B<:>I<value>...]>
-S<I<at-timestamp>B<@>I<value>[B<:>I<value>...]>
+B<rrdtool> {B<update> | B<updatev>} I<filename>
+S<[B<--template>|B<-t> I<ds-name>[B<:>I<ds-name>]...]>
+S<[B<--daemon> I<address>]>
+S<B<N>|I<timestamp>B<:>I<value>[B<:>I<value>...]>
+S<I<at-timestamp>B<@>I<value>[B<:>I<value>...]>
S<[I<timestamp>B<:>I<value>[B<:>I<value>...] ...]>
=head1 DESCRIPTION
Note that depending on the arguments of the current and previous call to
update, the list may have no entries or a large number of entries.
+Since B<updatev> requires direct disk access, the B<--daemon> option cannot be
+used with this command.
+
=item I<filename>
The name of the B<RRD> you want to update.
While it appears possible with the template switch to update data sources
asynchronously, B<RRDtool> implicitly assigns non-COMPUTE data sources missing
-from the template the I<*UNKNOWN*> value.
+from the template the I<*UNKNOWN*> value.
Do not specify a value for a COMPUTE B<DST> in the B<update>
function. If this is done accidentally (and this can only be done
using the template switch), B<RRDtool> will ignore the value specified
for the COMPUTE B<DST>.
+=item B<--daemon> I<address>
+
+If given, B<RRDTool> will try to connect to the caching daemon L<rrdcached>
+at I<address> and will fail if the connection cannot be established. If the
+connection is successfully established the values will be sent to the daemon
+instead of accessing the files directly.
+
+For a list of accepted formats, see the B<-l> option in the L<rrdcached> manual.
+
=item B<N>|I<timestamp>B<:>I<value>[B<:>I<value>...]
The data used for updating the RRD was acquired at a certain
=back
-=head1 EXAMPLE
+=head1 ENVIRONMENT VARIABLES
+
+The following environment variables may be used to change the behavior of
+C<rrdtoolE<nbsp>update>:
+
+=over
+
+=item B<RRDCACHED_ADDRESS>
+
+If this environment variable is set it will have the same effect as specifying
+the C<--daemon> option on the command line. If both are present, the command
+line argument takes precedence.
+
+=back
+
+=head1 EXAMPLES
+
+=over
+
+=item *
C<rrdtool update demo1.rrd N:3.44:3.15:U:23>
Update the database file demo1.rrd with 3 known and one I<*UNKNOWN*>
value. Use the current time as the update time.
+=item *
+
C<rrdtool update demo2.rrd 887457267:U 887457521:22 887457903:2.7>
Update the database file demo2.rrd which expects data from a single
data-source, three times. First with an I<*UNKNOWN*> value then with two
regular readings. The update interval seems to be around 300 seconds.
-=head1 AUTHOR
+=item *
+
+C<rrdtool update --cache /var/lib/rrd/demo3.rrd N:42>
+
+Update the file C</var/lib/rrd/demo3.rrd> with a single data source, using the
+current time. If the caching daemon cannot be reached, do B<not> fall back to
+direct file access.
+
+=item *
+
+C<rrdtool update --daemon unix:/tmp/rrdd.sock demo4.rrd N:23>
+
+Use the UNIX domain socket C</tmp/rrdd.sock> to contact the caching daemon. If
+the caching daemon is not available, update the file C<demo4.rrd> directly.
+B<WARNING:> Since a relative path is specified, the following disturbing effect
+may occur: If the daemon is available, the file relative to the working
+directory B<of the daemon> is used. If the daemon is not available, the file
+relative to the current working directory of the invoking process is used.
+B<This may update two different files depending on whether the daemon could be
+reached or not.> Don't do relative paths, kids!
+
+=back
+
+=head1 AUTHORS
-Tobias Oetiker <oetiker@ee.ethz.ch>
+Tobias Oetiker <tobi@oetiker.ch>,
+Florian Forster <octoE<nbsp>atE<nbsp>verplant.org>