Re: [Virtuoso-users] Query performance with R2RML remote RDBMS SQL Server

/company/schneider-electric> FB > <https://www.youtube.com/schneidercorporate> FB > <https://instagram.com/schneiderelectric> FB > <https://plus.google.com/+schneiderelectric> > > > > > > > > > *From:*Kingsley Idehen [mailto:kide...@openlin

Re: [Virtuoso-users] Query performance with R2RML remote RDBMS SQL Server

FB > <https://www.linkedin.com/company/schneider-electric> FB > <https://www.youtube.com/schneidercorporate> FB > <https://instagram.com/schneiderelectric> FB > <https://plus.google.com/+schneiderelectric> > > > > > > > > &

Re: [Virtuoso-users] Query performance with R2RML remote RDBMS SQL Server

> [FB] <https://www.youtube.com/schneidercorporate> [FB] <https://instagram.com/schneiderelectric> [FB] <https://plus.google.com/+schneiderelectric> From: Kingsley Idehen [mailto:kide...@openlinksw.com] Sent: Thursday, November 03, 2016 9:30 PM To: virtuoso-users@lists.sourceforge.ne

Re: [Virtuoso-users] Query performance with R2RML remote RDBMS SQL Server

On 10/14/16 12:41 PM, CHARBEL EL KAED wrote: > > Hello, > > > > I would like to have your opinion on the following: > > > > I installed Virtuoso Enterprise on a Windows VM with: > > 8 cores > > 28 GB RAM > > 56 GB SSD > > > > I attached virtuoso configuration file. > > > > On virtuoso I hav

[Virtuoso-users] Query performance with R2RML remote RDBMS SQL Server

Hello, I would like to have your opinion on the following: I installed Virtuoso Enterprise on a Windows VM with: 8 cores 28 GB RAM 56 GB SSD I attached virtuoso configuration file. On virtuoso I have a local RDF Table with 8221 triples and a remote MS SQL Azure with 50 million records. A recor

Re: [Virtuoso-users] Query performance problem

And now for the amazing result: replacing the "?r nao:userVisible 1" with a bif:exists filter makes the query blazingly fast. Then again this is probably not that amazing after all since the query without the restriction is fast, thus, filtering on those results would be, too. Still, it is a fun

Re: [Virtuoso-users] Query performance problem

Hi Ivan, thanks a lot for your answer. Funnily enough your query version does not make a difference. The query takes about the same time. Sadly I cannot add any conditions on the graph since all is in different graphs. I know this is not great for Virtuoso but we use graphs for metadata on stateme

Re: [Virtuoso-users] Query performance problem

Hello Sebastian, One variant to check is select distinct ?r (bif:concat(bif:search_excerpt(bif:vector('lego'), ?v2))) as ?_n_f_t_m_ex_ where { {{select distinct ?r ?v2 where { ?r ?v1 ?v2 . ?v2 bif:contains 'lego' . ?r nao:userVisible "1"^^xsd:int . } limit 10 } }

[Virtuoso-users] Query performance problem

Hi list, as always my question is about query performance. The following very simple query performs very well on a V6.3rc1 with default indexes: select distinct ?r (bif:concat(bif:search_excerpt(bif:vector('lego'), ?v2))) as ?_n_f_t_m_ex_ where { { ?r ?v1 ?v2 . ?v2 bif:contai

Re: [Virtuoso-users] Query performance issues

YES! The new snapshot seems to solve the problem! Queries are lightning fast. Great work. Thanks a lot. :) On 06/01/2010 12:36 PM, Ivan Mikhailov wrote: > Hello Sebastian, > > Something is really weird with this case, because it works at the local > box. The most important question was whether th

Re: [Virtuoso-users] Query performance issues

Hi Ivan, On 06/01/2010 12:36 PM, Ivan Mikhailov wrote: > Something is really weird with this case, because it works at the local > box. The most important question was whether the database statistics are Do you mean that your local installation does not have the problem and the queries are both f

Re: [Virtuoso-users] Query performance issues

Hello Sebastian, Something is really weird with this case, because it works at the local box. The most important question was whether the database statistics are calculated correctly (if not then execution plans would be wrong in the majority of queries). The direct comparison of statistical estim

Re: [Virtuoso-users] Query performance issues

On 05/03/2010 12:55 PM, Kingsley Idehen wrote: > Sebastian Trüg wrote: >> Hi Ivan, >> >> while this is very good to know it is hard to do it generically. After >> all users and developers can create all sorts of queries. >> >> Thanks for the explanation. >> >> Can this be considered a bug in the qu

Re: [Virtuoso-users] Query performance issues

Sebastian Trüg wrote: Hi Ivan, while this is very good to know it is hard to do it generically. After all users and developers can create all sorts of queries. Thanks for the explanation. Can this be considered a bug in the query optimizer? Sebastian, Cost based Query Optimization is a bo

Re: [Virtuoso-users] Query performance issues

Hi Ivan, while this is very good to know it is hard to do it generically. After all users and developers can create all sorts of queries. Thanks for the explanation. Can this be considered a bug in the query optimizer? Cheers, Sebastian On 05/03/2010 10:20 AM, Ivan Mikhailov wrote: > Hello Seb

Re: [Virtuoso-users] Query performance issues

Hello Sebastian, With select * where { ?r a nfo:FileDataObject . ?r nfo:fileName ?f . ?f bif:contains 'breaking' . } the optimizer decides for some reason that being nfo:FileDataObject is much less frequent property of ?r than containing "breaking" word in a filename. That's weird decision becau

Re: [Virtuoso-users] Query performance issues

Hello Hugh, Please find the output attached to prevent line breaks. Cheers, Sebastian On 04/30/2010 03:14 AM, Hugh Williams wrote: > Hi Sebastian, > > Can you please provide the explain output detailing the execution plan for > both queries for comparison, as detailed at: > > http://doc

Re: [Virtuoso-users] Query performance issues

Hi Sebastian, Can you please provide the explain output detailing the execution plan for both queries for comparison, as detailed at: http://docs.openlinksw.com/virtuoso/perfdiag.html#perfdiagqueryplans http://docs.openlinksw.com/virtuoso/fn_explain.html Note you must include th

[Virtuoso-users] Query performance issues

Hello, using a V6 server with default indexes I would like to know why the following queries are different in performance. The store contains thousands of different graphs but adding a "graph ?g {}" around all patterns does not change the execution time. select * where { ?r a nfo:FileDataObject .

Re: [Virtuoso-users] Query performance

HI Sebastian, I suggest you read the following document: http://docs.openlinksw.com/virtuoso/rdfperformancetuning.html I did, don't ask me why I still messed up the indexes. I don't get enough sleep these days... I know the feeling :) Anyway, something is still unclear to me: In whic

Re: [Virtuoso-users] Query performance

On Tuesday 27 October 2009 21:42:15 Patrick van Kleef wrote: > I suggest you read the following document: > >http://docs.openlinksw.com/virtuoso/rdfperformancetuning.html I did, don't ask me why I still messed up the indexes. I don't get enough sleep these days... Anyway, something is still

Re: [Virtuoso-users] Query performance

Hi Sebastian, Indeed, I am only using the default indexes. Thanks a lot for the hint. I suppose I need indexes like gsop and gspo? OK, this is obviously BS. I think I need some private lessons in index design... anyway, I suppose something like SPOG POSG OPSG GSPO GPOS makes more sense? I w

Re: [Virtuoso-users] Query performance

On Tuesday 27 October 2009 20:12:34 Sebastian Trüg wrote: > Indeed, I am only using the default indexes. Thanks a lot for the hint. > I suppose I need indexes like gsop and gspo? OK, this is obviously BS. I think I need some private lessons in index design... anyway, I suppose something like SPO

Re: [Virtuoso-users] Query performance

Indeed, I am only using the default indexes. Thanks a lot for the hint. I suppose I need indexes like gsop and gspo? Cheers, Sebastian On Tuesday 27 October 2009 15:08:51 Ivan Mikhailov wrote: > Sebastian, > > What indexes are in use? It seems to me that only default indexes are > created, but p

Re: [Virtuoso-users] Query performance

Sebastian, What indexes are in use? It seems to me that only default indexes are created, but patterns with unspecified graph need, of course, two additional indexes. If the speed of the first query is suitable and you do not want to create additional indexes for some reason, consider select * w

[Virtuoso-users] Query performance

Just out of curiosity: why is there such a big difference in performance between the following 2 query variants (second one much slower than the first) select * where { ?r a nfo:FileDataObject . OPTIONAL { ?g ?r . } . FILTER(!BOUN