14:00:00 RRSAgent has joined #sparql 14:00:00 logging to http://www.w3.org/2010/06/15-sparql-irc 14:00:01 +kasei 14:00:02 RRSAgent, make logs world 14:00:04 Zakim, this will be 77277 14:00:04 ok, trackbot; I see SW_(SPARQL)10:00AM scheduled to start now 14:00:05 Meeting: SPARQL Working Group Teleconference 14:00:05 Date: 15 June 2010 14:00:05 rrsagent, smake logs world 14:00:05 I'm logging. I don't understand 'smake logs world', bglimm. Try /msg RRSAgent help 14:00:13 Zakim, mute me 14:00:13 sorry, kasei, I don't know what conference this is 14:00:13 rrsagent, set logs world 14:00:15 zakim, this is SPARQL 14:00:15 ok, LeeF; that matches SW_(SPARQL)10:00AM 14:00:21 Zakim, mute me 14:00:21 kasei should now be muted 14:00:35 SteveH__ has joined #sparql 14:00:36 +[IPcaller] 14:00:43 Scribe: bglimm 14:00:46 -MattPerry 14:00:47 zakim, IPCaller is me 14:00:47 +AndyS; got it 14:00:53 Zakim, who is here? 14:00:53 On the phone I see +86528aaaa, kasei (muted), AndyS 14:00:54 On IRC I see SteveH__, RRSAgent, AlexPassant, MattPerry, Zakim, bglimm, OlivierCorby, LeeF, iv_an_ru, SteveH, AndyS, karl, pgearon, kasei, sandro, trackbot 14:00:59 + +1.617.245.aabb 14:01:03 zakim, aabb is me 14:01:03 +LeeF; got it 14:01:05 Zakim, +86528aaaa is me 14:01:05 +bglimm; got it 14:01:16 scribe: bglimm 14:01:18 +MattPerry 14:01:24 ScribeNick: bglimm 14:02:08 Advanced regrets for 29/June. Will (still) be returning from the US. 14:02:45 -LeeF 14:02:47 +[Garlik] 14:02:56 Zakim, [Garlik] is temporarily me 14:02:56 +SteveH; got it 14:03:31 +Souri 14:03:33 +Lee_Feigenbaum 14:03:33 Souri has joined #sparql 14:03:45 zakim, who's on the phone? 14:03:45 On the phone I see bglimm, kasei (muted), AndyS, MattPerry, SteveH, Souri, Lee_Feigenbaum 14:04:05 Regrets: Axel, pgearon, Sandro, IvanH 14:04:13 Regrets: Axel, Paul, Ivan 14:04:22 Agenda: http://www.w3.org/2009/sparql/wiki/Agenda-2010-06-15 14:04:34 last week's minutes: http://www.w3.org/2009/sparql/meeting/2010-06-08 14:04:39 Regrets continued: Sandro 14:04:55 +??P27 14:05:01 NickH has joined #sparql 14:05:02 Zakim: ??p27 is me 14:05:10 Zakim, ??p27 is me 14:05:10 +AlexPassant; got it 14:05:25 Zakim, who is on the call? 14:05:25 On the phone I see bglimm, kasei (muted), AndyS, MattPerry, SteveH, Souri, Lee_Feigenbaum, AlexPassant 14:05:27 tel server does not recognize when I deal sparql code 14:06:12 OlivierCorby, disconnect and try again 14:06:24 RESOLVED: Approve minutes at http://www.w3.org/2009/sparql/meeting/2010-06-08 14:06:57 Next meeting: 2010-06-29 @ 15:00 UK / 10:00 EDT 14:06:58 I keep getting disconnected from the UK number 14:07:02 Lee: Andy has already send regrets from 29 July 14:07:17 SteveH strongly at risk for 6/29 14:07:21 Stve: I am at risk, unlikely to make it actually 14:07:35 NickH, apparently zakim is having troubles - solution is to either keep trying or to try the US number if you can 14:07:43 s/Stve/SteveH/ 14:08:00 LeeF: new comment about the HTTP protocol 14:08:01 +??P21 14:08:13 ... Chime can say something about that 14:08:14 Zakim, ??21 is me 14:08:14 sorry, NickH, I do not recognize a party named '??21' 14:08:19 ... nothing new from RIF 14:08:20 Zakim, ??P21 is me 14:08:20 +NickH; got it 14:08:38 ... RDF2RDF will have a F2F in CA and has published their use cases 14:08:47 +OlivierCorby 14:08:54 s/RDF2RDF/RDB2RDF/ 14:09:23 ... W3C might set up a WG for governments to handle linked data 14:09:55 Dedicated teleconference on test cases: June 30th, 15:00 BST (10:00 EDT) 14:09:57 ... time for test cases call is Wed Jun 30, 3pm UK time, 10am US Eastern 14:10:13 ... some test cases in emails 14:10:28 ... make sure we have a place to put these 14:10:36 topic: SemTech 14:10:55 ... SemTec plans: we have a SPARQL 1.1 panel at Wed 2pm local time 14:11:03 ... same as the one at ISWC 14:12:06 ... Is there interest in meeting informally outside of the panel? 14:12:18 Be good to informally meet up 14:12:29 I won't be there 14:12:57 Agendum: Function Library 14:13:15 LeeF: Axel is fleshing out the design on a wiki page 14:13:18 topic: zero-length paths 14:13:31 .... 0-length path semantics is stilll undefined 14:13:50 ... everything in the world, everything in the graph 14:14:14 See Andy's suggestion at http://lists.w3.org/Archives/Public/public-rdf-dawg/2010AprJun/0360.html 14:14:49 ... AndyS suggested compromise that 0-length matches any subject and object node in the DS and constant subj./obj. IRIs in the triple pattern 14:15:01 q+ 14:15:05 ack SteveH 14:15:26 SteveH: I might miss something, but if you have: 14:15:58 ?x :p{0,1} ?y, I would expect that to match only triples with that 14:15:59 ?x :p{0,1} ?y 14:16:01 predicate 14:16:23 ?x :p{0} ?y 14:16:28 LeeF: Lets consider first ?x p{0} ?y 14:16:45 or bnodes 14:16:52 So are we saying every property is reflexive? 14:17:00 ... gives all pairs of (iri, iri) for IRIs that occur in the graph as sub. or obj 14:17:02 ?x :p _:foo 14:17:13 I don't think 14:18:04 Do you mean ?x :p{0} _:foo? 14:18:09 :p . :p . :p 14:18:12 -AlexPassant 14:18:27 :q / 14:18:39 ?x :p* ?y 14:18:56 :p* ?y 14:19:08 That just gives I guess 14:19:35 :q 14:19:37 +[IPcaller] 14:19:51 Zakim, ??ipcaller is me 14:19:51 sorry, AlexPassant, I do not recognize a party named '??ipcaller' 14:20:05 Zakim, ??[IPcaller] is me 14:20:05 sorry, AlexPassant, I do not recognize a party named '??[IPcaller]' 14:20:22 LeeF: we will have some more test cases for this, to illustrate what are expected results 14:20:37 PROPOSED: Zero-length paths are defined to match all subjects and objects in the graph plus any IRI literal that is the subject or object of the triple pattern. 14:20:49 Zakim, ??IPcaller is me 14:20:49 sorry, AlexPassant, I do not recognize a party named '??IPcaller' 14:20:49 Zakim, ??ipcaller is AlexPassant 14:20:50 sorry, bglimm, I do not recognize a party named '??ipcaller' 14:22:17 We could just have + and no * and number must be greater than 0 in path length restrictions... 14:22:43 Tentative consensus on the fact that zero-length paths are defined to match all subjects and objects in the graph plus any IRI literal that is the subject or object of the triple pattern. 14:22:52 Encourage further discussion & test cases and will solicit external feedbcak 14:23:27 Agendum: SPARQL UPDATE and service keyword 14:23:43 LeeF: Steve did send an email regarding this 14:23:44 http://lists.w3.org/Archives/Public/public-rdf-dawg/2010AprJun/0267.html 14:24:58 LeeF: Do we have to define atomicity or any other issues we have to define? 14:25:25 SteveH: We could say that we do not define atomicity. 14:25:37 LeeF: What do implementations do? 14:26:13 AndyS: depends a bit on the implementation, depends on the underlying datasource 14:26:25 ... whether it supports transactions 14:26:34 ... in one case you would deadlock 14:26:51 ... it would attemot to get a write lock on something that is already locked 14:27:03 ... there is no lock coordination 14:27:30 SteveH: Our implementation would also do that. 14:27:52 actually, it wouldn't, but it did in the past 14:28:09 Leef: Should we say that implementors should care about how they handle concurrency? 14:29:02 SteveH: A user might not know that two endpoints are actually the same endpoint 14:29:18 LeeF: Not clear what we can do to prevent this 14:29:53 .... we say that multiple operations should be atomic, but we cannot really specify it more 14:30:43 LeeF: At one point we said that update queries just use SPARQL 1.0 queries, but I think we changed that to SPARQL 1.1 at some point 14:31:08 AndyS: You could do the same as service does in the example with load 14:31:37 SteveH: It is worth a note in the security section because it can be part of a DoS attack 14:31:46 Advice to editor: consider a note in the security section about the interplay of SERVICE & LOAD against the endpoint handling an Update request 14:33:17 LeeF: We need to do a review of the open issues 14:33:31 ... understand the most important open issues for the docuemmnts 14:33:47 s/docuemmnts/documents/ 14:34:08 .... Axel and I need to write an overview document about the different parts of the spec 14:34:26 Topic: Aggregates 14:34:48 LeeF: AndyS and SteveH tried to highlight the most important issues here 14:35:09 ... Andy asked what does SELECT * mean in conjunction with GROUP BY clause 14:35:29 ... SELECT * could be an error if the query mentions variables not in the group by 14:35:42 q+ 14:35:42 ... we could also only collect vars in the group by clause 14:35:47 ack SteveH 14:35:54 I prefer option 1 14:36:02 example: SELECT * { ... ?x ... ; ... ?y ... } GROUP BY ?x 14:36:18 is that (1) an error (projecting ?y which is not in GROUP BY) or (2) a valid query that projects just ?x ? 14:36:31 marginal preference for (2) 14:36:36 but very marginal 14:36:45 2 would project ut ?y before aggregating 14:36:51 s/ut/out/ 14:36:57 I would say this is an error 14:37:00 in SQL it will be an error 14:37:13 hm, maybe I'm changing my mind 14:37:13 I prefer to have it like SQL with error 14:38:08 In Oracle, "select * from scott.emp group by ename;" returns "ORA-00979: not a GROUP BY expression" 14:39:26 pref option 2 14:39:32 LeeF: In IRC, I see strong support for 1 14:39:43 I prefer 2 slightly, though it's a pretty strange query... 14:40:10 marginal preference for 2 14:40:15 er, 1 14:40:24 straw poll - #1 is error and #2 is projects just the group by key variables 14:40:30 1 14:40:33 prefer 1 14:40:36 2 14:40:37 #2 14:40:38 1 14:40:38 2 14:40:39 prefer 1 14:40:48 0 14:41:14 3:1 for option 1 14:41:19 3:2 14:41:32 Yes, I can't count 14:41:35 :) 14:41:43 4:3 for option 1 14:41:54 4 for #1 , 3 for #2, and 1 for #0 14:42:14 LeeF: No convincing decision, we should bring it to the attention of the group and get more feedback 14:42:17 ha. I prefer #2, but support #1 by default because it just explodes when I try executing the query. 14:42:21 ... create more test cases 14:42:39 ACTION: Lee to craft a test case for SELECT * ... GROUP BY and solicit implementor, WG, and community feedback 14:42:39 Created ACTION-257 - Craft a test case for SELECT * ... GROUP BY and solicit implementor, WG, and community feedback [on Lee Feigenbaum - due 2010-06-22]. 14:43:02 So did you change your vote kasei? 14:43:27 bglimm, no. 14:43:28 LeeF: There was discussion about GROUP BY without having an aggregate 14:43:41 just means I need to do more impl. work. 14:43:46 ah 14:44:21 LeeF: wrong reference 14:45:09 ... I waned to go back to what AndyS called null aggregation 14:45:19 which leads me to a fairly natural interpretation of 14:45:19 SELECT ?s ?p 14:45:19 { 14:45:19 ?s ?p ?p 14:45:19 } GROUP BY ?s ?p 14:45:20 AndyS: I'll type a small example 14:45:20 as "null aggregation" 14:45:21 Example: SELECT ?s { ?s ?p ?o } GROUP BY ?s 14:46:01 but is has GROUP BY for all projected vars, so should be fine 14:46:52 AndyS: It could be aggregation that just does nothing 14:47:04 SteveH: It could be an imolicit SAMPLE 14:47:15 s/imolicit/implicit/ 14:47:32 AndyS: but here the var is not necessarily in the key 14:47:40 SteveH: That's not a problem 14:47:55 SELECT SAMPLE(?s) { ?s ?p ?o } GROUP BY ?s 14:48:22 SELECT (?o+1 AS ?e) { ?s ?p ?o } GROUP BY ?o+1 14:48:41 That's scary 14:48:46 SELECT (?o+1 AS ?e) { ?s ?p ?o } GROUP BY ?o 14:49:13 SteveH: That should be legal 14:49:38 LeeF: Must the expressions be functional? 14:49:46 SELECT (rand(?o) AS ?e) { ?s ?p ?o } GROUP BY ?o 14:49:59 which of those first two is meant to be legal? 14:50:09 SELECT (?o AS ?e) { ?s ?p ?o } GROUP BY ?o 14:50:15 AndyS: Going back to the use of sample, that must be carefully worded 14:50:45 SteveH: The renaming happens later in the algebra, so that is not a problem 14:51:09 SELECT (SAMPLE(?o)+1 AS ?e) { ?s ?p ?o } GROUP BY ?o 14:51:17 AndyS: If we have the ?o+1, we need to have ?o available later on 14:53:00 LeeF: I am interested in understanding which queries are legal and which ones are not in an email, so that we agree 14:53:40 SteveH: I so far based the definitions on the F2F decisions, algebra got complicated though 14:53:42 If we do go for "SELECT *" withGROUP BY is illegal, I'm presuming this *not* a grammar issue 14:53:49 ... we can revise if too complicated 14:53:55 ACTION: Steve to summarize which queries are legal and not in terms of expressions in GROUP BY and expressions in the SELECT clause that deal with group by keys and with aggregators 14:53:55 Created ACTION-258 - Summarize which queries are legal and not in terms of expressions in GROUP BY and expressions in the SELECT clause that deal with group by keys and with aggregators [on Steve Harris - due 2010-06-22]. 14:53:57 AndyS, doesn't seem like one 14:54:02 q? 14:54:37 LeeF: Last issue: AndyS asked about composite keys give an implicit sorting 14:55:01 ... Is that something that is or is not in the current draft? 14:55:28 http://lists.w3.org/Archives/Public/public-rdf-dawg/2010AprJun/0348.html 14:55:40 yup 14:55:41 yes 14:56:13 SteveH: I am not sure I understand the issue 14:56:23 ...question 14:57:18 3 Y 14:57:19 Sou you wouldn't get 3 Y, 1 A, 3 X, ... 14:57:21 1A 14:57:37 Wouldn't you add an order by for that guarantee 14:57:37 no 14:57:39 SteveH: The current algebra does nt guarantee anything 14:57:50 ... you have to put an order by clause 14:58:15 AndyS: My implementation would not give a guarantee, uses hash sets 14:58:27 I would be in favor of not guranteeing an order 14:58:42 SteveH: It seems too much to require that since we have an explicit order by clause that can be used if required 14:58:56 s/guranteeing/guaranteeing / 14:59:03 LeeF: Seems easy then, no guarantee is given on the ordering 14:59:15 LeeF: Any other business? 14:59:29 AndyS: The syntax issue for Union and MINUS 14:59:51 ... for Union, we coud not require left hand side brackets 15:00:13 s/coud/could/ 15:00:14 SteveH: I thought we wanted it to be more like optional 15:00:44 I thought so as well, and would prefer it to work syntactically like optional. 15:00:55 LeeF: I think we agreed we shouldn't require braces on the left-hand side part, but no firm decision 15:01:18 .... if you are interested in these syntax issues, take a look at Andy's mail and get involved 15:01:38 see you in SF next week 15:01:38 .... see you at SemTec or until 29th. 15:01:41 bye all 15:01:42 adjourned 15:01:43 -Souri 15:01:44 -Lee_Feigenbaum 15:01:45 -SteveH 15:01:45 bye 15:01:48 bye! 15:01:48 -[IPcaller] 15:01:49 -OlivierCorby 15:01:50 -MattPerry 15:01:51 -NickH 15:01:54 Zakim, unmute me 15:01:54 kasei should no longer be muted 15:02:01 -bglimm 15:02:56 should I be able to rewrite this: { ?x !(a|^a) ?y } 15:02:59 as this: { ?x !a ?y } UNION { ?y !a ?x } 15:05:07 :p{0} 15:07:18 { ?x !(A|B|C|^D|^E) ?y } => { ?x !(A|B|C) ?y } UNION { ?y !(D|E) ?x } 15:08:01 Does anybody know who NickH is? scribe agent complains 15:08:12 as the perl member, I suspect that job falls to me :) 15:08:12 zakim, who is on the phone? 15:08:12 On the phone I see kasei, AndyS 15:08:20 we are on the phone. 15:10:35 bglimm, Nick Humfrey, from the BBC 15:10:42 Ah, thanks 15:10:47 -kasei 15:11:35 -AndyS 15:11:36 SW_(SPARQL)10:00AM has ended 15:11:38 Attendees were kasei, MattPerry, AndyS, +1.617.245.aabb, LeeF, bglimm, SteveH, Souri, Lee_Feigenbaum, AlexPassant, NickH, OlivierCorby, [IPcaller] 15:11:42 OlivierCorby has left #sparql 15:35:52 SteveH has joined #sparql 15:42:40 bglimm, thanks for scribing! 17:28:32 Zakim has left #sparql 19:29:40 AndyS has joined #sparql 20:02:58 SteveH has joined #sparql 22:16:57 LeeF has joined #sparql 22:46:16 karl has joined #sparql