Hey all, I would like to also voice my support of Jeroen's requests -- these features are indeed essential to geographic queries (being able to sort by distance). I believe it is possible to do in the same manner in which 'where' statements are able to be modified by extensions (I have written up a beta expansion of SM and SMW to do this a few months ago - not using the built in GIS mysql features however but the haversine formula).
Right now I have an unadulterated SMW installation with about ~30million pages, ~23million of them have geographic coordinates. Distance queries take about ~240 seconds across them if loaded for the first time (lots of time building temp tables). Running Dual i7, 12gb ram - 8gb innodb buffer, 4x 7200 1tb drives in raid 10. We are beginning to look into external stores - but with so much data and other work the testing and transfer would take some time. We've also had to remove Semantic Drilldown and turn off auto-completion in Semantic Forms (be careful of Type:Page, automatically uses auto-completion). -Tom p.s. Apologies for the really really bad distance query in the original SMW, was my first time working with SMW, and was impossible to do bounding-box with lat/lon being stored in the same field in MySQL ;) On Wed, Feb 23, 2011 at 2:09 PM, Jeroen De Dauw <jeroended...@gmail.com>wrote: > Hey, > > Since this discussion is about performance and changes to the SMW storage > layer, I'd like to bring up an issue I've been having as Semantic Maps dev. > > To efficiently do spatial operations on geographical data stored by SMW, > support for spatial extensions in MySQL and PostGis in PostGres is needed. > Currently there is no way to make use of these database extensions, as the > SMW storage layer does not allow for: > * specifying what type of index to place on a field (it only allows > specifying a field should be indexed) > * putting SQL functions in insert and select statements (which is needed to > insert or select geographical entities) > > I'm not sure to what extend supporting this is possible, but it would make > a huge difference for working with geographical data in SMW. So I'd be nice > if this was kept into consideration when modifications to the storage layer > are made. > > In any case, the current distance query in Semantic Maps already performs > way better then the one in older versions of SMW (which was really really > ... really bad). More incentive for Wikia to update :) > > Cheers > > -- > Jeroen De Dauw > http://www.bn2vs.com > Don't panic. Don't be evil. > -- > > > ------------------------------------------------------------------------------ > Free Software Download: Index, Search & Analyze Logs and other IT data in > Real-Time with Splunk. Collect, index and harness all the fast moving IT > data > generated by your applications, servers and devices whether physical, > virtual > or in the cloud. Deliver compliance at lower cost and gain new business > insights. http://p.sf.net/sfu/splunk-dev2dev > _______________________________________________ > Semediawiki-devel mailing list > Semediawiki-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/semediawiki-devel > >
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