big spell checking patch -- slif@bellsouth.net

[rrdtool.git] / doc / rrdupdate.pod

diff --git a/doc/rrdupdate.pod b/doc/rrdupdate.pod
index bc4e902..50a656e 100644 (file)
--- a/doc/rrdupdate.pod
+++ b/doc/rrdupdate.pod
@@ -1,14 +1,15 @@
 =head1 NAME
 
 =head1 NAME
 

-rrdtool update - Store a new set of values into the rrd
+rrdtool update - Store a new set of values into the RRD

 
 =for html <div align="right"><a href="rrdupdate.pdf">PDF</a> version.</div>
 
 =head1 SYNOPSIS
 
 
 =for html <div align="right"><a href="rrdupdate.pdf">PDF</a> version.</div>
 
 =head1 SYNOPSIS
 

-B<rrdtool> B<update> I<filename> 
+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<[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>...]> 

 S<[I<timestamp>B<:>I<value>[B<:>I<value>...] ...]>
 
 =head1 DESCRIPTION
 S<[I<timestamp>B<:>I<value>[B<:>I<value>...] ...]>
 
 =head1 DESCRIPTION


@@ -19,39 +20,63 @@ which the data is written.
 
 =over 8
 
 
 =over 8
 

+=item B<updatev>
+
+This alternate version of B<update> takes the same arguments and
+performs the same function. The I<v> stands for I<verbose>, which
+describes the output returned. B<updatev> returns a list of any and all
+consolidated data points (CDPs) written to disk as a result of the
+invocation of update. The values are indexed by timestamp (time_t),
+RRA (consolidation function and PDPs per CDP), and data source (name).
+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.
+

 =item I<filename>
 
 The name of the B<RRD> you want to update.
 
 =item B<--template>|B<-t> I<ds-name>[B<:>I<ds-name>]...
 
 =item I<filename>
 
 The name of the B<RRD> you want to update.
 
 =item B<--template>|B<-t> I<ds-name>[B<:>I<ds-name>]...
 

-by default, the update function expects the data input in the order,
-the data sources are defined in the RRD. This is not very error
-resistant, as you might be sending the wrong data into a RRD.
+by default, the B<update> function expects the data input in the order
+the data sources are defined in the RRD, excluding any COMPUTE data sources 
+(i.e. if the third data source B<DST> is COMPUTE, the third input value
+will be mapped to the fourth data source in the B<RRD>). This is not very
+error resistant, as you might be sending the wrong data into a RRD.

 
 The template switch allows you to specify which data sources you are
 going to update and in which order. If the data sources specified in
 
 The template switch allows you to specify which data sources you are
 going to update and in which order. If the data sources specified in

-the template are not available in the rrd file, the update process
+the template are not available in the RRD file, the update process

 will abort with an error message.
 
 will abort with an error message.
 

+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. 
+
+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<N>|I<timestamp>B<:>I<value>[B<:>I<value>...]
 
 The data used for updating the RRD was acquired at a certain time. This
 time can either be defined in seconds since 1970-01-01. Or by using the
 letter 'N' the update time is set to be the current time. Negative time
 values are subtracted from the current time.
 =item B<N>|I<timestamp>B<:>I<value>[B<:>I<value>...]
 
 The data used for updating the RRD was acquired at a certain time. This
 time can either be defined in seconds since 1970-01-01. Or by using the
 letter 'N' the update time is set to be the current time. Negative time
 values are subtracted from the current time.

+An AT_STYLE TIME SPECIFICATION (see the I<rrdfetch> documentation) may
+also be used by delimiting the end of the time specification with the '@' character
+instead of a ':'.

 Getting the timing right to the second is especially
 important when you are working with data-sources of type B<COUNTER>,
 B<DERIVE> or B<ABSOLUTE>. 
 
 The remaining elements of the argument are DS updates. The order of this list is
 Getting the timing right to the second is especially
 important when you are working with data-sources of type B<COUNTER>,
 B<DERIVE> or B<ABSOLUTE>. 
 
 The remaining elements of the argument are DS updates. The order of this list is

-the same as the order the data sources were defined in the rra.
+the same as the order the data sources were defined in the RRA.

 If there is no data for a certain data-source, the letter 
 B<U> (eg. N:0.1:U:1) can be defined.
 
 The format of the value acquired from the data source is dependent of the
 data source type chosen. Normally it will be numeric, but the data acquisition
 If there is no data for a certain data-source, the letter 
 B<U> (eg. N:0.1:U:1) can be defined.
 
 The format of the value acquired from the data source is dependent of the
 data source type chosen. Normally it will be numeric, but the data acquisition

-modules my impose their very own parsing of this parameter as long as the colon
+modules may impose their very own parsing of this parameter as long as the colon

 (B<:>) remains the data source value separator.
 
 =back
 (B<:>) remains the data source value separator.
 
 =back