Hi Hugh, Reason #1: The Virtuoso tuning guide suggested:
"If predicate and graph are given but subject is not, then it is sometimes useful to add: CREATE BITMAP INDEX RDF_QUAD_PGOS ON DB.DBA.RDF_QUAD (G, P, O, S) PARTITION (O VARCHAR (-1, 0hexffff));" The instructions did not indicate for this index, that any prior indexes need to be dropped, so, I did not drop any. SQL> STATISTICS DB.DBA.RDF_QUAD; Showing SQLStatistics of table(s) 'DB.DBA.RDF_QUAD' TABLE_QUALIFIER TABLE_OWNER TABLE_NAME NON_UNIQUE INDEX_QUALIFIER INDEX_NAME TYPE SEQ_IN_INDEX COLUMN_NAME COLLATION CARDINALITY PAGES FILTER_CONDITION VARCHAR VARCHAR VARCHAR SMALLINT VARCHAR VARCHAR SMALLINT SMALLINT VARCHAR VARCHAR INTEGER INTEGER VARCHAR _______________________________________________________________________________ DB DBA RDF_QUAD NULL NULL NULL 0 NULL NULL NULL NULL NULL NULL DB DBA RDF_QUAD 0 DB RDF_QUAD 3 1 P NULL NULL NULL NULL DB DBA RDF_QUAD 0 DB RDF_QUAD 3 2 S NULL NULL NULL NULL DB DBA RDF_QUAD 0 DB RDF_QUAD 3 3 O NULL NULL NULL NULL DB DBA RDF_QUAD 0 DB RDF_QUAD 3 4 G NULL NULL NULL NULL DB DBA RDF_QUAD 1 DB RDF_QUAD_GS 3 1 G NULL NULL NULL NULL DB DBA RDF_QUAD 1 DB RDF_QUAD_GS 3 2 S NULL NULL NULL NULL DB DBA RDF_QUAD 1 DB RDF_QUAD_OP 3 1 O NULL NULL NULL NULL DB DBA RDF_QUAD 1 DB RDF_QUAD_OP 3 2 P NULL NULL NULL NULL DB DBA RDF_QUAD 1 DB RDF_QUAD_POGS 3 1 P NULL NULL NULL NULL DB DBA RDF_QUAD 1 DB RDF_QUAD_POGS 3 2 O NULL NULL NULL NULL DB DBA RDF_QUAD 1 DB RDF_QUAD_POGS 3 3 S NULL NULL NULL NULL DB DBA RDF_QUAD 1 DB RDF_QUAD_POGS 3 4 G NULL NULL NULL NULL DB DBA RDF_QUAD 1 DB RDF_QUAD_SP 3 1 S NULL NULL NULL NULL DB DBA RDF_QUAD 1 DB RDF_QUAD_SP 3 2 P NULL NULL NULL NULL Reason #2: The manual (the same URL actually) indicates that sometimes the indexes can become "polluted" and that "Dropping and recreating the index will remedy this situation." So, therefore, I am experimenting/hacking/playing so that I can become stronger with the Force. ;-) In any event, was there anything I needed to do prior to adding the above index? I had performed the test with a newly created database. - Erich Erich Bremer http://www.ebremer.com On 10/14/2013 10:53 PM, Hugh Williams wrote: > Hi Erich, > > Why are you creating these additional indexes and if you did were the > defaults dropped first ? What does the the following query return: > > STATISTICS DB.DBA.RDF_QUAD; > > Which should return a list of indexes on the RDF_QUAD table ... > > As indicated in the performance tuning guide the default indexes should > suffice for most use cases, thus you should not have to create additional > indexes ... > > 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 14 Oct 2013, at 13:56, Erich Bremer <er...@ebremer.com> wrote: > >> Either way, I get the following error when starting my bulk load: >> *** glibc detected *** virtuoso-t: double free or corruption (out): >> 0x00007f6b710f2000 *** >> Segmentation fault >> >> - Erich >> >> Erich Bremer >> http://www.ebremer.com >> >> The default schema as per the below URL is: >> CREATE DISTINCT NO PRIMARY KEY REF BITMAP INDEX RDF_QUAD_SP >> ON RDF_QUAD (S, P) >> PARTITION (S INT (0hexffff00)); >> >> CREATE BITMAP INDEX RDF_QUAD_POGS >> ON RDF_QUAD (P, O, G, S) >> PARTITION (O VARCHAR (-1, 0hexffff)); >> >> CREATE DISTINCT NO PRIMARY KEY REF BITMAP INDEX RDF_QUAD_GS >> ON RDF_QUAD (G, S) >> PARTITION (S INT (0hexffff00)); >> >> CREATE DISTINCT NO PRIMARY KEY REF INDEX RDF_QUAD_OP >> ON RDF_QUAD (O, P) >> PARTITION (O VARCHAR (-1, 0hexffff)); >> >> Given this, I noticed that the below index PGOS uses DB.DBA.RDF_QUAD (G, >> P, O, S), shouldn't that be DB.DBA.RDF_QUAD (P, G, O, S)? >> >> - Erich >> >> Hi, >> >> I tried creating the index as per the page: >> >> http://virtuoso.openlinksw.com/dataspace/doc/dav/wiki/Main/VirtRDFPerformanceTuning >> >> CREATE BITMAP INDEX RDF_QUAD_PGOS ON DB.DBA.RDF_QUAD (G, P, O, S) >> PARTITION (O VARCHAR (-1, 0hexffff)); >> >> which successfully creates via ISQL (seemingly), but when I go to >> execute a bulk load across 8 cores, Virtuoso >> dies with a segmentation core dump. The same bulk load works fine >> without creating the above index. >> Did I miss something in the creation of the index? - Erich >> >> Erich Bremer >> http://www.ebremer.com >> >> >> >> ------------------------------------------------------------------------------ >> October Webinars: Code for Performance >> Free Intel webinars can help you accelerate application performance. >> Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from >> the latest Intel processors and coprocessors. See abstracts and register > >> http://pubads.g.doubleclick.net/gampad/clk?id=60134071&iu=/4140/ostg.clktrk >> _______________________________________________ >> Virtuoso-users mailing list >> Virtuoso-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/virtuoso-users ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. 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