Igor, my understanding is that even in the UPDATE case it is not a simple value replacement that happens ... but I would be most interested in your tests, stability and performance of such a solution ... you can do this with mockup configs without actually re-writing rrdtool.
cheers tobi Today Sfiligoi Igor wrote: > Tobias Oetiker wrote: > > Hi Igor, > > > > Yesterday Igor Sfiligoi wrote: > > > >> Hi Kevin and Tobi. > >> > >> Since you are planning to radically change the format, have you considered > >> going a more "standard" way? > >> > >> Instead of having a completely RRDTool specific format, use something > >> other tools could easily read? > >> > >> What about SQLite? > >> It is already portable. > >> And it is a database ;) > >> > >> It should be pretty easy to define a schema that serves RRDTool well. > >> > >> Would it be worth a consideration? > >> > >> Igor > > > > yes the thought has crossed my mind, the problem with SQL databases > > is that they are not realy good at updating round robin archives, > > du to transactional consistancy constraints they will create > > internal fragmentation which will cause performance to suffer > > dramatically. > > > > BUT it would be an interesting thought to see, if we can abstract > > the interface enough so that writing a 'plugin' for an sqlite > > storage backend becomes easy ... > > > > cheers > > tobi > What if the table had a structure like this: > index,date,value(1,value2,...) > > with index the table key. > I.e. very similar to what you have now in the RRD file. > > One would populate all the rows with consecutive indexes and > date=NULL,valueX=NULL at creation time. > The updates would be SQL UPDATEs on the existing row, i.e. replacing > date+valueX at a specific index. > > No INSERTs, no DELETEs. > This should keep the database compact and of fixed size. > > Do you still see a fragmentation problem under this conditions? > > Cheers, > Igor > > > -- 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 [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/rrd-developers
