SPARQL Working Group Teleconference Minutes, 12 October 2010

Lee Feigenbaum: Looking at the end of last week's minutes, I'm not sure of an example that differentiates between "in place" and "end of gorup" semantics for binds, given the resolution that to use simple (error to assign to in-scope variable) semantics ←

Lee Feigenbaum: Lee Feigenbaum: WHERE { ?x ns:q ?v . KW(?two := 2*?v) . ?x ns:q: ?two } ← ←

Lee Feigenbaum: Lee Feigenbaum: in place semantics: the above is allowed ← ←

Lee Feigenbaum: Lee Feigenbaum: end of group semantics: the above is an error ← ←

Zakim IRC Bot: ok, trackbot; I see SW_(SPARQL)10:00AM scheduled to start in 6 minutes ←

Zakim IRC Bot: On IRC I see SteveH, NickH, RRSAgent, OlivierCorby, LeeF, AxelPolleres, cbuilara_, AndyS, ivan, iv_an_ru, AlexPassant, pgearon, trackbot, ericP, kasei, sandro ←

Lee Feigenbaum: in particular, the equivalence you give would have been the join/filter semantics, not the simple semantics ←

Zakim IRC Bot: ok, trackbot; I see SW_(SPARQL)10:00AM scheduled to start in 4 minutes ←

Lee Feigenbaum: Well, the subquery equivalence doesn't make it an error to project a variable that's then bound in the same scope as the subquery ←

Lee Feigenbaum: and that's what the group decided (simple semantics) to do for bind/assignment ←

Zakim IRC Bot: On IRC I see SteveH, NickH, RRSAgent, OlivierCorby, LeeF, AxelPolleres, cbuilara_, AndyS, ivan, iv_an_ru, AlexPassant, pgearon, trackbot, ericP, kasei, sandro ←

Axel Polleres: LeeF, I thought that order-dependence means that only the use of var within P1 (ie on the rhs of assignment) would be restricted? ←

Lee Feigenbaum: I can live with that, though I probably won't change my implementation to do it that way, since I think it's weird :) ←

Zakim IRC Bot: On the phone I see NickH, SteveH, AxelPolleres, AndyS, OlivierCorby, Ivan, kasei, MattPerry, +1.617.553.aaaa, bglimm (muted) ←

Carlos Buil Aranda: I can't connect to the phone, I'm using skype and I do not have a phone that allows me to make international calls :( ←

Trackbot IRC Bot: Created ACTION-322 - Draft a reply to GK-1 and Gk-2 [on Steve Harris - due 2010-10-19]. ←

I'm not sure I liked the draft to the wiki page, but it should be searchable ←

Andy Seaborne: there are so many possible cases, I don't see anythig fundamnetal on this one ←

Trackbot IRC Bot: Created ACTION-323 - Draft reply on GK-3 [on Axel Polleres - due 2010-10-19]. ←

Lee Feigenbaum: thanks very much to Birte for writing up the steps to prepare docs for publication!! ←

Lee Feigenbaum: alternative meaning is { { SELECT * (Expr AS ?var) { P1 . P2 } } } ←

Axel Polleres: assignment is order dependent because which part is on the left depends on whats inside and whats outside ←

Lee Feigenbaum: Axel's version ("in place" semantics) -- the bind operator "breaks up" a group ←

Lee Feigenbaum: "end of group" semantics just shoves all assignments to the "bottom"/"end" of the group ←

Andy Seaborne: Lee's test case: WHERE { ?x ns:q ?v . KW(?two := 2*?v) . ?x ns:q: ?two } ←

Zakim IRC Bot: LeeF, listening for 10 seconds I heard sound from the following: AndyS (9%) ←

Axel Polleres: { ?x ns:q ?v . KW(?two := 2*?v) . ?x ns:q: ?two KW(?two := 3*?v) ←

Lee Feigenbaum: alternative meaning is { { SELECT * (Expr AS ?var) { P1 . P2 } } } ←

Ivan Herman: yes, but that means order dependence without {}s, in basic model grap patterns are not order dep ←

... on the mental model side we introduce something with order dep, I don't like that ←

Lee Feigenbaum: right, people like to write their queries in the order they expect it to execute ←

... I don't think many people think of FILTERS as floating, but it happens to work out ←

Axel Polleres: 1) order dependent { P1 KW(Expr AS ?Var) P2} =:= { { SELECT * ←

Axel Polleres: 2) oder-indepentent { P1 KW(Expr AS ?Var) P2} =:= { { SELECT * ←

... I would propose to implement one, see what comments we get then go ahead ←

Axel Polleres: conclusion: go ahead with option 1) noting that we have some reservations. ←

Andy Seaborne: preference is related to pt. 2, BIND goes with AS, LET better with := ←

Andy Seaborne: BIND AS (at this current moment) May change based on experience ←

Axel Polleres: if there are comments we might change, but we have a solution everyone can live with ←

Paul Gearon: people I've spoken to don't have an intuition re. BIND, we know what it means ←

Lee Feigenbaum: Surprised to hear that, since (expr AS ?var) is pretty much exactly what SQL does ←

Paul Gearon: sure, I agree that people understand "AS". It's actually the word "BIND" that is the problem. ←

Lee Feigenbaum: with SteveH, pgearon, bglimm, OlivierCorby, cbuilara_ abstaining ←

Paul Gearon: [on the basis that I would prefer different syntax, but agree with the principle] ←

... current doc is quite restrictive, any failed svc fails query, do we want that ←

... on drawback is order in which call is executed is implicit, determined by engine ←

Steve Harris: order-intependence is appealing, but want to hear from someone who implemented it [ Scribe Assist by Axel Polleres ] ←

Axel Polleres: current doc says variable must be bound, but doesn't explain meaning ←

Gregory Williams: if were going with var. endpoints I think better would be potentiall bound that we've already got ←

Gregory Williams: I think the query planner has to know that the var is potentially bound otherwise users will never be able to figure it out ←

Gregory Williams: SteveH, my ideas on why that might be useful were within UNIONs and OPTIONALs ←

15:00:09 <SteveH> parallel with FILTER errors

parallel with FILTER errors ←

15:00:29 <SteveH> AndyS: have other comments on doc to deal with

Andy Seaborne: have other comments on doc to deal with ←

15:00:44 <SteveH> ... kasei's is significant

... kasei's is significant ←

15:00:58 <kasei> the content was mostly good, but it's in a very different style...

Gregory Williams: the content was mostly good, but it's in a very different style... ←

15:01:01 <SteveH> AxelPolleres: more dicussion on ML please

Axel Polleres: more dicussion on ML please ←

15:01:08 <ivan> zakim, drop me

Ivan Herman: zakim, drop me ←

15:01:08 <Zakim> Ivan is being disconnected

Zakim IRC Bot: Ivan is being disconnected ←

15:01:10 <Zakim> -Ivan

Zakim IRC Bot: -Ivan ←

15:01:20 <bglimm> Zakim, unmute me

Birte Glimm: Zakim, unmute me ←

15:01:20 <Zakim> bglimm should no longer be muted

Zakim IRC Bot: bglimm should no longer be muted ←

15:02:15 <SteveH> bye

bye ←

15:02:18 <Zakim> -SteveH

Zakim IRC Bot: -SteveH ←

15:02:19 <Zakim> - +1.617.553.aaaa

Zakim IRC Bot: - +1.617.553.aaaa ←

15:02:22 <bglimm> bye

Birte Glimm: bye ←

15:02:24 <SteveH> AndyS, good!

AndyS, good! ←

15:02:26 <Zakim> -kasei

Zakim IRC Bot: -kasei ←

15:02:28 <Zakim> -bglimm

Zakim IRC Bot: -bglimm ←

15:02:31 <Zakim> -NickH

Zakim IRC Bot: -NickH ←

15:02:32 <Zakim> -OlivierCorby

Zakim IRC Bot: -OlivierCorby ←

15:02:35 <AxelPolleres> nothing on the official ISWC sched�ule. but we should meet up

Axel Polleres: nothing on the official ISWC sched�ule. but we should meet up ←

15:02:37 <Zakim> -pgearon

Zakim IRC Bot: -pgearon ←

15:02:40 <AndyS> kasei ?

Andy Seaborne: kasei ? ←

15:02:43 <Zakim> -AxelPolleres

Zakim IRC Bot: -AxelPolleres ←

15:02:44 <cbuilara_> bye

Carlos Buil Aranda: bye ←

15:02:47 <Zakim> -AndyS

Zakim IRC Bot: -AndyS ←

15:02:48 <AxelPolleres> adjourned

Axel Polleres: adjourned ←

15:02:48 <kasei> yes?

Gregory Williams: yes? ←

15:03:05 <Zakim> -??P27

Zakim IRC Bot: -??P27 ←

15:03:06 <Zakim> SW_(SPARQL)10:00AM has ended

Zakim IRC Bot: SW_(SPARQL)10:00AM has ended ←

15:03:07 <Zakim> Attendees were AxelPolleres, [IPcaller], AndyS, OlivierCorby, SteveH, NickH, Ivan, kasei, MattPerry, +1.617.553.aaaa, bglimm, pgearon

Zakim IRC Bot: Attendees were AxelPolleres, [IPcaller], AndyS, OlivierCorby, SteveH, NickH, Ivan, kasei, MattPerry, +1.617.553.aaaa, bglimm, pgearon ←

15:03:07 <AndyS> Do you have an impl of SPARQL HTTP I can test against?

Andy Seaborne: Do you have an impl of SPARQL HTTP I can test against? ←

15:03:23 <kasei> the REST stuff?

Gregory Williams: the REST stuff? ←

15:03:34 <AndyS> StveH, ditto - what's a good 4Store public server to test against?

Andy Seaborne: StveH, ditto - what's a good 4Store public server to test against? ←

15:03:39 <AndyS> yes - REST stuff

Andy Seaborne: yes - REST stuff ←

15:03:49 <AndyS> SteveH, ditto - what's a good 4Store public server to test against?

Andy Seaborne: SteveH, ditto - what's a good 4Store public server to test against? ←

15:03:57 <kasei> i don't think so... KjetilK has a partial implementation somewhere, but I'm not sure how complete it is...

Gregory Williams: i don't think so... KjetilK has a partial implementation somewhere, but I'm not sure how complete it is... ←

15:04:06 <SteveH> AndyS, hm... BBC guys have one, don't know URI offhand

AndyS, hm... BBC guys have one, don't know URI offhand ←

15:05:06 <kasei> i've mostly focused on query/update/service description so far...

Gregory Williams: i've mostly focused on query/update/service description so far... ←

15:05:21 <AndyS> OK - will see if BBC has a public facing one.  (not sure it's publically accessible - only via a web appl)

Andy Seaborne: OK - will see if BBC has a public facing one. (not sure it's publically accessible - only via a web appl) ←

15:05:30 <kasei> interested in the http stuff, but it's on the back burner

Gregory Williams: interested in the http stuff, but it's on the back burner ←

15:05:39 <SteveH> AndyS, what were you hoping to test, most people firewall off update for e.g.

AndyS, what were you hoping to test, most people firewall off update for e.g. ←

15:05:53 <AndyS> kasei, what does "implement service description" cover?

Andy Seaborne: kasei, what does "implement service description" cover? ←

15:05:55 <SteveH> AndyS, I think the SPARQL endpoint is publically accessible

AndyS, I think the SPARQL endpoint is publically accessible ←

15:06:05 <AndyS> SteveH, GET and HEAD => graph naming tests

Andy Seaborne: SteveH, GET and HEAD => graph naming tests ←

15:06:14 <SteveH> I don't think we impl. GET

I don't think we impl. GET ←

15:06:24 <kasei> hooking it up to the endpoint code and getting dataset descriptions, available extensions functions, etc. in place...

Gregory Williams: hooking it up to the endpoint code and getting dataset descriptions, available extensions functions, etc. in place... ←

15:06:39 <AndyS> kasei, ack

Andy Seaborne: kasei, ack ←

15:07:44 <kasei> Andy, it's a bit sparse, but see for example: http://triplr.org/turtle/myrdf.us/sparql11

Gregory Williams: Andy, it's a bit sparse, but see for example: http://triplr.org/turtle/myrdf.us/sparql11 ←

15:08:41 <AndyS> got to run

Andy Seaborne: got to run ←

15:13:21 <AxelPolleres> thanks all...

Axel Polleres: thanks all... ←

15:13:31 <AxelPolleres> rrsagent, make records public

Axel Polleres: rrsagent, make records public ←

Formatted by CommonScribe

This revision (#1) generated 2010-10-12 15:27:41 UTC by 'apollere2', comments: None

SPARQL Working Group Teleconference

Minutes of 12 October 2010

1. comments

2. publication status

3. LET/BIND/assignment

4. federation