Thank you Luigi, this is more or less what I expected. Cheers, Riccardo
2015-06-12 7:57 GMT+02:00 Luigi Dell'Aquila <luigi.dellaqu...@gmail.com>: > Hi guys, > > I'd like to shed some light on this "magic" :-) > > a RID is made of two numbers (a short and a long, at this stage, but the > first one will become a long too in next releases, it's in the radmap). > Say the RID is #xxx:yyy > > xxx is the cluster ID, it identifies the cluster where the record is > stored. OrientDB keeps a 1-1 mapping from this number to a file on the > filesystem (the cluster file, well, two files actually). > yyy is the cluster position, it defines the physical position where the > record is stored in the cluster file. > > The cluster is actually made of two files, one is the "directory" of > cluster positions and the second one contains the actual data. > The first file contains fixed size records that contain physical pointers > to positions in the second file. > > Now let's do a practical example > > #12:20 = {@class="Person", name="Luigi"} > > 1) OrientDB translates 12 -> "person" cluster > 2) person.cpm is the "directory" for that cluster, person.pcl contains data > 3) say every entry in the directory is N bytes long, OrientDB seeks in > person.pcm at position N*20 (20 is the cluster position) > 4) at this position it will find another number, say 12345, this is the > position of the record content in person.pcl > > So to resume you are doing two constant time operations, a direct seek in > person.cpm and another one in person.pcl > > Luigi > > > > > > 2015-06-11 11:59 GMT+02:00 James Wang <jwang25...@gmail.com>: > >> agreed >> >> >> On Thursday, 11 June 2015 06:38:06 UTC+1, scott molinari wrote: >>> >>> I was wondering, is an index automatically created on the RID? I would >>> imagine it is, just wanted to be sure. >>> >>> Also, are there any plans to create something like a sparse index in >>> MongoDB? Or does Orient already have this capability? >>> >>> Scott >>> >> -- >> >> --- >> You received this message because you are subscribed to the Google Groups >> "OrientDB" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to orient-database+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > > --- > You received this message because you are subscribed to the Google Groups > "OrientDB" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to orient-database+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- --- You received this message because you are subscribed to the Google Groups "OrientDB" group. To unsubscribe from this group and stop receiving emails from it, send an email to orient-database+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.