Hi Martin, since there seems to be no opposition on the ML and I quite like your patch, only touching little existing code, I have included it into trunk.
cheers tobi Monday Martin Sperl wrote: > Hi! > > As some of you may know that I have created a patch for rrdtool 1.2 a few > years ago, so that a database could be queried for values for graphing. > > I have created an updated patch for rrdtool version 1.3 (against SVN version > 1644). > > The patch has been mostly rewritten and the following changes have been made: > > * high dependency on mysql has been reduced by avoiding the > temporary tables (which was bad for mysql replication) > * The number of executed SQL-Statements for one CDEF has been > reduced to 1 compared to 11 SQLs (including CREATE TEMPORARY > TABLE) - for patch against version 1.2 > * All consolidation is done in rrdtool itself (MIN,MAX,AVERAGE) > * Additional consolidation functions are COUNT and SIGMA, which give > information on statistics on a per "time-bin" basis. > * All these consolidation values are always returned as separate > columns, that are returned by RRD and the consolidation function > given as Argument is ignored. > Main reason is that this way there is only one call to rrd_fetcht > and thus the database even if we need to fetch for example min, > avg and max. Compare this to 3 calls in case of different > consolidation functions - and if you want to get SIGMA and COUNT > as well it is still only one call to the backend and the database. > * Some previous existing features have been taken out at the moment > to allow for this reduced set of SQL queries. > o prediction using the values from the last X days at the same > time > o the corresponding sigma calculation > * The idea is to create generic CDEF's that will do the same thing, > but that is also available when using RRD-files (similar to TREND, > but with another scope) > This will get posted as a separate patch. > * Overall performance should be much better and the patch as a whole > simpler. > * The patch also includes modifications to the configuration > infrastructure, to make libdbi support optional. > > As requested by Tobi in a private email-thread, the patch should be highly > localized (and configurable via configure), to allow a possible merge with > minimal shared code touched. > > Please review the code and comment... > > Thanks, > Martin > > P.s: I know that there is the "new" approach of rrdcached to improve > write-performance with massive updates on rrd. This patch was an initial > attempt to get a similar problem solved. > Here for comparison: our production system (running with the 1.2 patch for > graphing) is updating on average 150k different values every 300 seconds or > approximately 500 values/s on a HP-DL360G3 with Dual Xenon 3.0GHz, 4GB RAM > connected via ISCSI (over GBit network) to our storage system. (data-gathering > Application and the mysql DB is done on the same host) > -- Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland http://it.oetiker.ch [EMAIL PROTECTED] ++41 62 775 9902 / sb: -9900 _______________________________________________ rrd-developers mailing list rrd-developers@lists.oetiker.ch https://lists.oetiker.ch/cgi-bin/listinfo/rrd-developers
