- From: Renato Golin <renato@ebi.ac.uk>
- Date: Wed, 26 Sep 2007 10:32:00 +0100
- To: "Emanuele D'Arrigo" <manu3d@gmail.com>
- CC: Semantic Web Interest Group <semantic-web@w3.org>, "public-owl-dev@w3.org" <public-owl-dev@w3.org>
Emanuele D'Arrigo wrote: > Hi everybody! > > Has any consensus been reached on the architecture for efficient storage > and retrieval of an ontology's triples? Hi Manu, I'm quite interested in triplet storages but what I found is that there is no consensus nor standard for anything in that area. There are several storage engines but each one doing it's own way. Also, the support to query languages is quite random. > I've read an interesting paper about a triple store based on hashed tables > that intuitively sounded more efficient than a straightforward > one-table approach. Given the amount of data you can have the hash table might not fit in any computer and even if it fits, I/O will become a huge problem. This is a common misconception that hash tables are always faster than lists but that's not true, especially when you have bigger hash tables than your memory can hold (not that difficult). The only way to have an efficient and still powerful storage engine is to mix standards. For very local queries, hashes can be a good solution. For locally distributed queries, lists and binary indexes might perform better. But for truly distributed queries (outside of your domain) you need an adaptive indexing system. The more distributed you go slower it is, but that's acceptable when you reckon the quality of your data will be higher that way. > Are there alternatives? Where can I learn more about this specific aspect? More alternatives than standards... see the Wiki pages to learn more: http://esw.w3.org/topic/FrontPage http://esw.w3.org/topic/SemanticWebTools http://esw.w3.org/topic/CommercialProducts http://esw.w3.org/topic/Semantic_Bioinformatics (storage at the end) cheers, --renato -- Reclaim your digital rights, eliminate DRM, learn more at http://www.defectivebydesign.org/what_is_drm
Received on Wednesday, 26 September 2007 09:33:54 UTC