X-Git-Url: https://git.octo.it/?p=rrdtool.git;a=blobdiff_plain;f=doc%2Frrdcached.pod;h=a346d601f6cddc5d13b65df15737a868378c5320;hp=98376a11009a0576b51a63d6028d55c3a41a27dc;hb=f090c6d208157d252bf806fea2107b9e318424d4;hpb=baa76240855b60e459bce9e1c3330fe74235b7a0 diff --git a/doc/rrdcached.pod b/doc/rrdcached.pod index 98376a1..a346d60 100644 --- a/doc/rrdcached.pod +++ b/doc/rrdcached.pod @@ -125,10 +125,23 @@ used. updated by the daemon, assuming the base directory "/tmp". +B The paths up to and including the base directory B +symbolic links. In other words, if the base directory is +specified as: + + -b /base/dir/somewhere + +... then B of the following should be symbolic links: + + /base + /base/dir + /base/dir/somewhere + =item B<-B> -Only permit writes into the base directory specified in B<-b>. This does -B detect symbolic links. Paths containing C<../> will also be blocked. +Only permit writes into the base directory specified in B<-b> (and any +sub-directories). This does B detect symbolic links. Paths +containing C<../> will also be blocked. =back @@ -172,7 +185,7 @@ The daemon reports errors in one of two ways: During startup, error messages are printed to C. One of the steps when starting up is to fork to the background and closing C - after this writing directly to the user is no longer possible. Once this has happened, the daemon will send log messages -to the system logging daemon using L. The facility used it +to the system logging daemon using L. The facility used is C. =head1 HOW IT WORKS @@ -224,7 +237,8 @@ to disk. +---+----+---+ +------+-----+ +---+----+---+ ! File: foo ! ! File: bar ! ! File: qux ! ! First: 101 ! ! First: 119 ! ! First: 180 ! - ! Next: ---+--->! Next: ---+---> ... --->! Next: - ! + ! Next:&bar -+--->! Next:&... -+---> ... --->! Next:NULL ! + | Prev:NULL !<---+-Prev:&foo !<--- ... ----+-Prev: &... ! +============+ +============+ +============+ ! Time: 100 ! ! Time: 120 ! ! Time: 180 ! ! Value: 10 ! ! Value: 0.1 ! ! Value: 2,2 ! @@ -361,6 +375,15 @@ sent B the node has been dequeued. Causes the daemon to start flushing ALL pending values to disk. This returns immediately, even though the writes may take a long time. +=item B I + +Shows any "pending" updates for a file, in order. The updates shown have +not yet been written to the underlying RRD file. + +=item B I + +Removes I from the cache. Any pending updates B. + =item B [I] Returns a short usage message. If no command is given, or I is @@ -398,6 +421,10 @@ Adds more data to a filename. This is B operation the daemon was designed for, so describing the mechanism again is unnecessary. Read L above for a detailed explanation. +Note that rrdcached only accepts absolute timestamps in the update values. +Updates strings like "N:1:2:3" are automatically converted to absolute +time by the RRD client library before sending to rrdcached. + =item B I This command is written to the journal after a file is successfully @@ -405,6 +432,36 @@ written out to disk. It is used during journal replay to determine which updates have already been applied. It is I valid in the journal; it is not accepted from the other command channels. +=item B + +This command initiates the bulk load of multiple commands. This is +designed for installations with extremely high update rates, since it +permits more than one command to be issued per read() and write(). + +All commands are executed just as they would be if given individually, +except for output to the user. Messages indicating success are +suppressed, and error messages are delayed until the client is finished. + +Command processing is finished when the client sends a dot (".") on its +own line. After the client has finished, the server responds with an +error count and the list of error messages (if any). Each error messages +indicates the number of the command to which it corresponds, and the error +message itself. The first user command after B is command number one. + + client: BATCH + server: 0 Go ahead. End with dot '.' on its own line. + client: UPDATE x.rrd 1223661439:1:2:3 <--- command #1 + client: UPDATE y.rrd 1223661440:3:4:5 <--- command #2 + client: and so on... + client: . + server: 2 Errors + server: 1 message for command 1 + server: 12 message for command 12 + +=item B + +Disconnect from rrdcached. + =back =head2 Performance Values @@ -432,10 +489,11 @@ daemon was started. =item B I<(unsigned 64bit integer)> -Total number of "data sets" written to disk since the daemon was started. A -data set is one or more values passed to the B command. For example: -C is one data set with two values. The term "data set" is used to -prevent confusion whether individual values or groups of values are counted. +Total number of "data sets" written to disk since the daemon was +started. A data set is one or more values passed to the B +command. For example: C<1223661439:123:456> is one data set with two +values. The term "data set" is used to prevent confusion whether +individual values or groups of values are counted. =item B I<(unsigned 64bit integer)>