X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=doc%2Frrdgraph_data.txt;h=338b264d71437403d3ea7e7583e109d8ebc596d6;hb=06ef6a573e296977f34f9153039a377fb96c407b;hp=8dab92a357335642b6dd4cd4054c38d7d9e4c6b6;hpb=b4e87090e25c68f2ee17d5a63bfa213091121976;p=pkg-rrdtool.git diff --git a/doc/rrdgraph_data.txt b/doc/rrdgraph_data.txt index 8dab92a..338b264 100644 --- a/doc/rrdgraph_data.txt +++ b/doc/rrdgraph_data.txt @@ -25,7 +25,7 @@ DDEESSCCRRIIPPTTIIOONN ters "A-Z, a-z, 0-9, -,_" and a maximum length of 255 characters. When picking variable names, make sure you do not choose a name that is - already taken by an RPN operator. A save bet it to use lowercase or + already taken by an RPN operator. A safe bet it to use lowercase or mixedcase names for variables since operators will always be in upper- case. @@ -75,7 +75,7 @@ VVDDEEFF Example: "VDEF:avg=mydata,AVERAGE" - Note that currently only agregation functions work in VDEF rpn expres- + Note that currently only aggregation functions work in VDEF rpn expres- sions. Patches to change this are welcome. CCDDEEFF @@ -89,6 +89,32 @@ CCDDEEFF Example: "CDEF:mydatabits=mydata,8,*" +AAbboouutt CCDDEEFF vveerrssuuss VVDDEEFF + At some point in processing, RRRRDDttooooll has gathered an array of rates + ready to display. + + CCDDEEFF works on such an array. For example, _C_D_E_F_:_n_e_w_=_d_s_0_,_8_,_* would mul- + tiply each of the array members by eight (probably transforming bytes + into bits). The result is an array containing the new values. + + VVDDEEFF also works on such an array but in a different way. For example, + _V_D_E_F_:_m_a_x_=_d_s_0_,_M_A_X_I_M_U_M would scan each of the array members and store the + maximum value. + + WWhheenn ddoo yyoouu uussee VVDDEEFF vveerrssuuss CCDDEEFF?? + + Use CCDDEEFF to transform your data prior to graphing. In the above exam- + ple, we'd use a CCDDEEFF to transform bytes to bits before graphing the + bits. + + You use a VVDDEEFF if you want _m_a_x_(_1_,_5_,_3_,_2_,_4_) to return five which would be + displayed in the graph's legend (to answer, what was the maximum value + during the graph period). + + If you want to apply 'complex' operations to the result of a VDEF you + have to use a CDEF again since VDEFs only look like RPN expressions, + they aren't realy. + SSEEEE AALLSSOO rrdgraph gives an overview of how rrrrddttooooll ggrraapphh works. rrdgraph_data describes DDEEFF,CCDDEEFF and VVDDEEFF in detail. rrdgraph_rpn describes the RRPPNN @@ -100,8 +126,9 @@ SSEEEE AALLSSOO AAUUTTHHOORR Program by Tobias Oetiker - This manual page by Alex van den Bogaerdt + This manual page by Alex van den Bogaerdt with + corrections and/or additions by several people -1.3.1 2008-03-15 RRDGRAPH_DATA(1) +1.3.99909060808 2009-04-29 RRDGRAPH_DATA(1)