Rob Vesse kirjoitti 16.11.2017 klo 13:13:
This is by design. As has been discussed in the past tdbloader2 produces
maximally packed B+Trees by preprocessing data which will minimise disk space
usage.
[...]
As Andy mentioned on an earlier thread tdb2.tdbloader essentially has the
same behaviour as tdbloader, because of the different data structures low
performance should be much better anyway and he did not think there would be
much benefit to having a tdb2.tdbloader2 variant. Also given the different Data
structures I’m not sure if this would be as practical.
Right. I was just surprised at how big the difference is.
tdbloader2 is both fast and space-efficient, that makes it a lot more
appealing than tdb2.tdbloader which in my (very limited) experience is
slow and space-hungry (but similar to tdbloader for TDB1).
But the real surprise was the space overhead of named graphs. More than
twice the space just because I decide to put the data in a named graph
instead of the default graph? And that seems to be the case both for
TDB1 (both tdbloader and tdbloader2) and TDB2.
-Osma
--
Osma Suominen
D.Sc. (Tech), Information Systems Specialist
National Library of Finland
P.O. Box 26 (Kaikukatu 4)
00014 HELSINGIN YLIOPISTO
Tel. +358 50 3199529
[email protected]
http://www.nationallibrary.fi
