HDT is primarily on disk. Whether it is query-able depends on the exact
encoding, there is one encoding designed primarily for transportation of data
and another designed for querying called HDT-FoQ aka focused on querying
In either case, there will be some memory usage as they do perform some
caching. They may also take advantage of memory mapped files similar to what
TDB does.
As far as comparisons with TDB I have never done any myself. For simplistic
queries, I would expect that HDT performs ok since from what I remember the
indexing is suitable for simple scans. However, for queries with any kind of
complexity i.e. Filters, negations, Joins etc. I would expect TDB to outperform
it and will scale far better.
But as I always point out on these kinds of questions your use case will
matter. If you think one solution will be better than the other for your use
case then you should benchmark that yourself. Generic benchmarking will only
tell you so much and give you a general indication of comparative performance.
Rob
On 04/04/2017 07:03, "Lorenz B." <buehm...@informatik.uni-leipzig.de> wrote:
Well, I'm not that familiar with HDT, thus, I'm probably wrong. And I
saw right now that they also provide some kind of indexing concept.
Let's wait for response from Andy and/or Rob.
(In the meantime, I'll play around with HDT and Jena today to get some
more insights. )
>> Jena HDT is in-memory, right?
> Is it? I thought it was a on-disk, compressed, and query-able list of
quads...
>
--
Lorenz Bühmann
AKSW group, University of Leipzig
Group: http://aksw.org - semantic web research center
