Thanks for your insights. Best Regards, > JackB ----Messaggio originale---- Da: "Paul Houle" <ontolo...@gmail.com> Data: 12/09/2016 17.49 A: "Davis, Daniel (NIH/NLM) [C]"<daniel.da...@nih.gov> Cc: "Hugh Williams"<hwilli...@openlinksw.com>, "virtuoso-users@lists. sourceforge.net"<virtuoso-users@lists.sourceforge.net> Ogg: Re: [Virtuoso-users] Out of curiosity, some questions about OpenSource Virtuoso settings
The trouble with classic http is that pretty frequently you wind up making a separate TCP connection for each API call. In theory there was pipelining in http/1.1 but it did not really work and was rarely implemented in "web service" scenarios. http/2 has pipelining that works, reduces the # of round trips to do encryption, compresses headers, and has all sorts of goodness. Another issue is that http-based protocols have historically been text-based protocols and if there was useful thing I learned in grad school it was that you can do an awful lot of FLOPS in the time that it takes to parse a string like "7.55523135E12". Prior to 2000, it was common to see a wide range of text-based formats for structured data such as HL7, UN/EDIFACT, the communication packets used in amateur radio, etc. In the 2000-2010 period, XML ate most of that. In 2010-present, JSON has replaced XML in a lot of places. As people catch on to what JSON-LD really means (you can paint on the XML semantics that are missing in JSON with a minimum of bother), JSON will grow. Performance-wise you can get much better results with binary formats and people today are even realizing (slower than with JSON-LD) you can implement binary formats in LD in a secure way in C, unlike text formats. The interesting thing though is that "general" binary formats are nowhere near the consolidation we've seen with XML and JSON. Binary XML formats have been tried and not caught on outside of niches. A small community speaks Binary FIX. There is protocol buffers, Captain Proto, Thrift, Avro, MessagePack, and who knows what else. Binary formats might never get their XML moment because once you start caring about performance you care about performance for *your specific case* and thus it is impossible to pick one protocol that will make everybody equally happy (or miserable) Caching is another http family problem. Once you start caching you run into (a) the risk that cached data will be invalid, and (b) there is no guarantee that perceived performance will be better when you use a cache. It's is very hard for Homo Corporatus to understand that users (ex. customers, employees) experience latency, not throughput. (It's anathema to corporate ideology, for instance, that 9 women can't make a baby in 1 month -- I knew Sun was on the skids when they started talking about "Throughput Computing") A 5400 rpm hard drive typical in a laptop can spin around about twice in the time it takes my (awful) DSL connection to round trip to the Azure data center in Chicago, and any kind of I/O storm means it can take much longer than two spins to discover that something is not in the cache. It's certainly possible that http caching can improve perceived performance, but you can't take it for granted. On Mon, Sep 12, 2016 at 10:49 AM, Davis, Daniel (NIH/NLM) [C] <daniel. da...@nih.gov> wrote: Tangentially on JDBC/ODBC vs HTTP. HTTP is slow because of the transport, but JDBC/ODBC has more mature models of paging over results, pre-fetching, etc. I feel that RDF is mature as a Data format, but as a protocol it is not that mature. -----Original Message----- From: Hugh Williams [mailto:hwilli...@openlinksw.com] Sent: Monday, September 12, 2016 5:30 AM To: Lorenz Buehmann <buehm...@informatik.uni-leipzig.de> Cc: virtuoso-users@lists.sourceforge.net Subject: Re: [Virtuoso-users] Out of curiosity, some questions about OpenSource Virtuoso settings Hi Lorenz, In Virtuoso 7+ Vectored query execution [1] enables single, typically complex analytical types queries, to be broken down and executed on multiple threads. The INI file param that controls this is "ThreadsPerQuery" [2] , which controls the maximum number of threads that can be claimed from the thread pool by a single query, and there are other associated params details at [2] . [1] http://docs.openlinksw.com/virtuoso/vexqrparl.html [2] http://docs.openlinksw.com/virtuoso/vexqrparlconfp/ Best Regards Hugh Williams Professional Services OpenLink Software, Inc. // http://www.openlinksw.com/ Weblog -- http://www.openlinksw.com/blogs/ LinkedIn -- http://www.linkedin.com/company/openlink-software/ Twitter -- http://twitter.com/OpenLink Google+ -- http://plus.google.com/100570109519069333827/ Facebook -- http://www.facebook.com/OpenLinkSoftware Universal Data Access, Integration, and Management Technology Providers > On 12 Sep 2016, at 07:13, Lorenz Buehmann <buehm...@informatik.uni-leipzig. de> wrote: > > Hi, > > just as a follow-up question: > > I know it supports inter-query parallelization, but does it also support intra-query parallelization, i.e. using multiple threads to compute the result of a single query? If yes, which parameter is used to configure this? > > > Cheers, > > Lorenz > > On 12.09.2016 05:57, Kingsley Idehen wrote: >> On 9/10/16 10:41 PM, giacom...@libero.it >> wrote: >> >>> So, I have a bunch of questions about Virtuoso. >>> >>> * Are SPARQL queries performed concurrently (using the standard >>> virtuoso.ini configuration)? >>> >> Yes, Virtuoso is highly multi-threaded. In addition, it has >> vectorized query execution i.e., many query batches per thread, handled concurrently . >> >>> * Are Virtuoso transactions autocommittable, or there aren't any >>> kind of transactions when connecting to the ODBC driver? >>> >> Depends, by default you have Read Committed Isolation level. >> >>> * Does Virtuoso automatically performs triple indexing before query data? >>> >> No, it has indexes in place. >> >> >>> In >>> some systems I have to configure it manually. >>> * Does the usage of ODBC degradates the benchmarking of Virtuoso's >>> SPARQL query or the time required to store the triples within a given named graph? >>> >> No, if anything that's faster than HTTP. >> >> Links: >> >> [1] >> http://docs.openlinksw.com/virtuoso/isolation/ >> >> [2] >> >> http://wikis.openlinksw.com/VirtuosoWikiWeb/ChangeVirtuosoSDefaultTra >> nsactionIsolationLevel >> >> [3] >> http://docs.openlinksw.com/virtuoso/fn_log_enable.html >> >> [4] >> >> http://virtuoso.openlinksw.com/dataspace/doc/dav/wiki/Main/VirtRDFPer >> formanceTuning >> >> >> [5] >> >> http://virtuoso.openlinksw.com/dataspace/doc/dav/wiki/Main/VirtBulkRD >> FLoader#Running >> >> multiple Loaders >> >> >> Kingsley >> >> >>> Thanks in advance for any support, >>> >>>> JackB >>>> >>> -------------------------------------------------------------------- >>> ---------- _______________________________________________ >>> Virtuoso-users mailing list >>> >>> Virtuoso-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/virtuoso-users >>> >>> >>> >> >> >> >> --------------------------------------------------------------------- >> --------- >> >> >> >> _______________________________________________ >> Virtuoso-users mailing list >> >> Virtuoso-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/virtuoso-users > > ---------------------------------------------------------------------- > -------- _______________________________________________ > Virtuoso-users mailing list > Virtuoso-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/virtuoso-users ------------------------------------------------------------------------------ _______________________________________________ Virtuoso-users mailing list Virtuoso-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/virtuoso-users -- Paul Houle (607) 539 6254 paul.houle on Skype ontolo...@gmail.com Ontology2 Edition of DBpedia 2015-10https://aws.amazon. com/marketplace/pp/B01HMUNH4Q/http://ontology2.com/the-book/o2dbpedia-info.html http://ontology2.com/book/chapter2/part1/dbpedia-examples.html RDF: A new Slant http://ontology2.com/the-book/rdf-a-new-slant.html Data Lakes, Data Ponds, and Data Dropletshttp://ontology2.com/the-book/data- lakes-ponds-and-droplets.html ------------------------------------------------------------------------------ _______________________________________________ Virtuoso-users mailing list Virtuoso-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/virtuoso-users
