misc fixed and TREND and reduce functionality by

[rrdtool.git] / doc / rrdgraph_data.src

diff --git a/doc/rrdgraph_data.src b/doc/rrdgraph_data.src
index 9b9ec8a..1f8fcb7 100644 (file)
--- a/doc/rrdgraph_data.src
+++ b/doc/rrdgraph_data.src
@@ -1,8 +1,8 @@
 =include name
 
-=head1 SYNOPSYS
+=head1 SYNOPSIS
 
-B<DEF>:I<vname>=I<RRD file>:I<ds name>:I<CF>[:step=I<step size>][:<time range>>]
+B<DEF:>I<E<lt>vnameE<gt>>=I<E<lt>rrdfileE<gt>>:I<E<lt>ds-nameE<gt>>:I<E<lt>CFE<gt>>[:step=I<E<lt>stepE<gt>>][:start=I<E<lt>timeE<gt>>][:end=I<E<lt>timeE<gt>>][:reduce=I<E<lt>B<CF>E<gt>>]
 
 B<VDEF>:I<vname>=I<RPN expression>
 
@@ -13,22 +13,22 @@ B<CDEF>:I<vname>=I<RPN expression>
 These three instructions collect the data out of the B<RRD> files,
 optionally altering it (think of a bytes to bits conversion) and
 if desired you can define variables containing useful information
-such as maximum, mininimum etcetera. Two of the instructions use
+such as maximum, minimum etcetera. Two of the instructions use
 a language called B<RPN> which is described in its own manual page.
 
 =head1 DEF
 
-B<DEF>:I<vname>=I<RRD file>:I<ds name>:I<CF>[:step=I<step size>][:<time range>>]
+B<DEF:>I<E<lt>vnameE<gt>>=I<E<lt>rrdfileE<gt>>:I<E<lt>ds-nameE<gt>>:I<E<lt>CFE<gt>>[:step=I<E<lt>stepE<gt>>][:start=I<E<lt>timeE<gt>>][:end=I<E<lt>timeE<gt>>][:reduce=I<E<lt>B<CF>E<gt>>]
 
 This command fetches data from an B<RRD> file.  The virtual name
 I<vname> can then be used throughout the rest of the script. By
 default, an B<RRA> which contains the correct consolidated data
 at an appropriate resolution will be chosen.  The resolution can
-be overriden with the L<--step|rrdgraph/item_Time> option. 
-The resolution can again be overriden by specifying the B<step size>.
-I<Not yet implemented:> [ The time span of this data
-is the same as for the graph by default, you can override this by
-specifying the B<time range>. ]
+be overridden with the L<--step|rrdgraph/item_Time> option. 
+The resolution can again be overridden by specifying the B<step size>.
+The time span of this data is the same as for the graph by default,
+you can override this by specifying B<start and end>.  Remember to
+escape colons in the time specification!
 
 If the resolution of the data is higher than the resolution of off
 graph, the data will be further consolidated.  This may result in
@@ -39,10 +39,17 @@ a resolution of 1800 seconds per B<CDP>, you should create an
 image with width 400 and time span 400*1800 seconds (use appropriate
 start and end times, such as C<--start end-8days8hours>).
 
+If consolidation needs to be done, the B<CF> of the B<RRA> specified in the
+B<DEF> itself will be used to reduce the data density.  This behaviour can
+be changed using C<:reduce=I<E<lt>B<CF>E<gt>>>.  This optional parameter
+specifies the B<CF> to use during the data reduction phase.
+
 Example:
 
         DEF:ds0=router.rrd:ds0:AVERAGE
         DEF:ds0weekly=router.rrd:ds0:AVERAGE:step=7200
+        DEF:ds0weekly=router.rrd:ds0:AVERAGE:start=end-1h
+        DEF:ds0weekly=router.rrd:ds0:AVERAGE:start=11\:00:end=start+1h
 
 =head1 VDEF