Dear All, Thank you very much for your response. However, I am not able to understand the meaning of "inlined", "rosq", "artm" in Virtuoso's query plans. For exposition my question contains small example query.
Also how can I figure out which join algorithm is used by Virtuoso by looking at the output of explain? On Thu, Jul 28, 2016 at 11:50 AM, Maria Jackson <maria.jackson....@gmail.com> wrote: > I apologize for another mail, but I have a deadline tomorrow so I'll > greatly appreciate if you could please help with this a little. > > On Wed, Jul 27, 2016 at 9:45 PM, Maria Jackson > <maria.jackson....@gmail.com> wrote: >> I ran the following query on Virtuoso: >> >> [code]PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#> >> SELECT DISTINCT ?X >> WHERE >> {?X rdf:type Musician . >> ?X rdf:plays <http://Music>} >> [/code] >> >> The output of "explain" of this query is: >> [code]{ >> RDF_QUAD_POGS 4 rows(s_1_4_t1.S) >> P = ##plays , O = #/Music >> RDF_QUAD_POGS 0.8 rows(s_1_4_t0.S) >> inlined P = ##type , O = ##Musician , S = s_1_4_t1.S >> Distinct (s_1_4_t0.S) >> >> After code: >> 0: X := := artm s_1_4_t0.S >> 4: BReturn 0 >> Subquery Select(X) >> >> After code: >> 0: X := Call __ro2sq (X) >> 5: BReturn 0 >> Select (X) >> } >> [/code] >> >> Now I am unable to decipher the output of explain command. What do >> "ro2sq", "inlined" and "artm" mean? And which join algorithm (like >> Hash Join, Merge Join, Nested loop join, etc.) is Virtuoso using for >> this query? I need to understand Virtuoso's explain command in order >> to understand the reason for Virtuoso taking a long time to execute? ------------------------------------------------------------------------------ _______________________________________________ Virtuoso-users mailing list Virtuoso-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/virtuoso-users
