IRC log of sparql on 2009-08-11

Timestamps are in UTC.

13:47:31 [RRSAgent]
RRSAgent has joined #sparql
13:47:31 [RRSAgent]
logging to
13:47:33 [trackbot]
RRSAgent, make logs world
13:47:33 [Zakim]
Zakim has joined #sparql
13:47:35 [trackbot]
Zakim, this will be 77277
13:47:35 [Zakim]
ok, trackbot; I see SW_(SPARQL)10:00AM scheduled to start in 13 minutes
13:47:36 [trackbot]
Meeting: SPARQL Working Group Teleconference
13:47:36 [trackbot]
Date: 11 August 2009
13:47:40 [LeeF]
Zakim, this will be sparql
13:47:40 [Zakim]
ok, LeeF; I see SW_(SPARQL)10:00AM scheduled to start in 13 minutes
13:47:42 [LeeF]
Chair: LeeF
13:47:45 [LeeF]
Scribe: SimonS
13:47:47 [KjetilK]
KjetilK has joined #sparql
13:47:47 [LeeF]
Scribenick: SimonS
13:48:01 [LeeF]
Regrets: IvanH, pgearon, AndyS
13:48:24 [LeeF]
13:48:30 [LeeF]
LeeF has changed the topic to: Agenda -
13:51:13 [LeeF]
my connection's so good right now i'm considering using skype or vonage for the sparql call, instead of my cell phone
13:53:08 [SimonS]
SimonS has joined #sparql
13:55:37 [KjetilK]
wow, people have been active while I have been away
13:56:46 [LeeF]
don't you just hate when the world moves on while you're on holiday? :)
13:57:15 [swh_]
it's very depressing :)
13:58:12 [Zakim]
SW_(SPARQL)10:00AM has now started
13:58:19 [Zakim]
+ +1.518.276.aaaa
13:58:20 [Zakim]
13:58:25 [kasei]
Zakim, aaaa is me
13:58:25 [Zakim]
+kasei; got it
13:58:32 [kasei]
Zakim, mute me
13:58:36 [Zakim]
kasei should now be muted
13:58:40 [Zakim]
13:58:56 [LukeWM]
zakim, ??P11 is me
13:58:59 [Zakim]
+LukeWM; got it
13:59:00 [Zakim]
+ +1.207.735.aabb
13:59:07 [SteveH]
Zakim, aabb is me
13:59:07 [Zakim]
+SteveH; got it
13:59:08 [LukeWM]
Zakim, ??P11 is me
13:59:08 [Zakim]
I already had ??P11 as LukeWM, LukeWM
13:59:25 [Zakim]
13:59:38 [SimonS]
Zakim, ??P17 is me
13:59:38 [Zakim]
+SimonS; got it
14:00:04 [Zakim]
14:00:11 [SteveH]
I'm clling from home, in london, it's noisy :)
14:00:13 [SteveH]
so you'd know
14:00:15 [KjetilK]
Zakim. ??P18 is me
14:00:21 [SteveH]
ok, cool
14:00:23 [Zakim]
14:00:25 [AlexPassant]
Zakim, ??P20 is me
14:00:26 [Zakim]
+AlexPassant; got it
14:00:52 [LeeF]
zakim, who's on the phone?
14:00:53 [Zakim]
On the phone I see kasei (muted), LukeWM, LeeF, SteveH, SimonS, ??P18, AlexPassant
14:01:05 [Zakim]
14:01:16 [Zakim]
14:01:17 [Zakim]
14:01:18 [Zakim]
14:01:44 [Zakim]
14:02:03 [Zakim]
14:02:03 [KjetilK]
Zakim. ??P11 is me
14:02:08 [Zakim]
14:02:19 [bglimm]
bglimm has joined #SPARQL
14:02:20 [LukeWM]
Zakim, ??P31 is me
14:02:20 [Zakim]
+LukeWM; got it
14:02:31 [Zakim]
14:02:32 [chimezie]
chimezie has joined #sparql
14:02:35 [LeeF]
zakim, ??P18 is Orri
14:02:35 [Zakim]
+Orri; got it
14:02:38 [chimezie]
Zakim, what is the passcode?
14:02:38 [Zakim]
the conference code is 77277 (tel:+1.617.761.6200 tel:+ tel:+44.117.370.6152), chimezie
14:02:47 [KjetilK]
Zakim, mute me
14:02:47 [Zakim]
sorry, KjetilK, I do not know which phone connection belongs to you
14:02:48 [bglimm]
Zakim, bcuencagrau is bglimm
14:02:50 [Zakim]
+bglimm; got it
14:02:56 [KjetilK]
Zakim, who is talking
14:02:56 [Zakim]
I don't understand 'who is talking', KjetilK
14:02:59 [Zakim]
14:03:00 [KjetilK]
Zakim, who is talking?
14:03:07 [LeeF]
zakim, ??P11 is kjetilk
14:03:07 [Zakim]
+kjetilk; got it
14:03:10 [Zakim]
KjetilK, listening for 10 seconds I heard sound from the following: 10 (28%), ??P11 (49%), LeeF (36%)
14:03:26 [LeeF]
zakim, who's on the phone?
14:03:26 [Zakim]
On the phone I see kasei (muted), LeeF, SteveH, AlexPassant, john-l, AxelPolleres, kjetilk, Orri, LukeWM, bglimm
14:03:31 [KjetilK]
Zakim, mute me
14:03:31 [Zakim]
kjetilk should now be muted
14:03:32 [Zakim]
14:03:33 [Zakim]
14:03:43 [SimonS]
Zakim, ??P36 is me
14:03:43 [Zakim]
+SimonS; got it
14:04:22 [ericP]
RRSAgent, please dial ericP-office
14:04:22 [RRSAgent]
I'm logging. I don't understand 'please dial ericP-office', ericP. Try /msg RRSAgent help
14:04:30 [Zakim]
14:04:40 [Zakim]
+ +
14:04:40 [ericP]
Zakim, please dial ericP-office
14:04:40 [Zakim]
ok, ericP; the call is being made
14:04:41 [Zakim]
14:04:47 [chimezie]
Zakim, mute me
14:04:47 [Zakim]
Chimezie_Ogbuji should now be muted
14:04:49 [Prateek]
Prateek has joined #sparql
14:05:33 [iv_an_ru]
+ does not work, btw.
14:05:49 [iv_an_ru]
14:05:51 [LeeF]
iv_an_ru, are you on the call?
14:06:06 [iv_an_ru]
yes, via UK number
14:06:20 [LeeF]
zakim, aacc is iv_an_ru
14:06:20 [Zakim]
+iv_an_ru; got it
14:06:23 [LeeF]
zakim, who's here?
14:06:23 [Zakim]
On the phone I see kasei (muted), LeeF, SteveH, AlexPassant, john-l, AxelPolleres, kjetilk (muted), Orri, LukeWM, bglimm, Chimezie_Ogbuji (muted), SimonS, Prateek, iv_an_ru, EricP
14:06:26 [Zakim]
On IRC I see Prateek, chimezie, bglimm, SimonS, KjetilK, Zakim, RRSAgent, LukeWM, AxelPolleres, SteveH, LeeF, karl, john-l, iv_an_ru, kjetil, AlexPassant, trackbot, kasei, ericP
14:07:00 [SimonS]
LeeF: Topics for today are Aggregate design and discovering service descriptions
14:07:23 [LeeF]
topic: admin
14:07:30 [LeeF]
PROPOSED: Approve minutes at
14:07:53 [bglimm]
14:08:07 [LeeF]
RESOLVED: Approve minutes at
14:08:27 [LeeF]
Next meeting: 2009-08-18 @ 15:00 BST / 10:00 EDT, SimonKJ to scribe
14:08:34 [bglimm]
Next week I am on holiday
14:08:41 [LeeF]
14:08:51 [LeeF]
regrets next week: bglimm, orri
14:09:42 [LeeF]
wiki page for next F2F
14:10:08 [SimonS]
LeeF: F2F 1st week of November in Santa Clara.
14:10:09 [SteveH]
14:10:52 [SimonS]
... Please indicate your attendance on the Wiki
14:11:10 [chimezie]
Zakim, unmute me
14:11:10 [Zakim]
Chimezie_Ogbuji should no longer be muted
14:11:29 [KjetilK]
14:11:29 [chimezie]
Good question, I don't know off head (will need to chew on that).
14:11:37 [chimezie]
14:11:50 [SimonS]
LeeF: SPARQL group meeting Monday and Tuesday.
14:12:06 [KjetilK]
ack me
14:12:12 [LeeF]
ack kjetilk
14:12:31 [SimonS]
KletilK: how about a split meeting with video conferencing?
14:12:36 [bglimm]
+1 to KjetilK
14:12:39 [ericP]
q+ to talk about challenges
14:12:44 [ericP]
14:12:53 [ericP]
q+ to talk about tech challenges re: vid conf
14:13:05 [SimonS]
LeeF: might be possible, but huge time difference, European side needs to how night owls.
14:13:13 [SimonS]
14:13:36 [bglimm]
I would fly just for the 2 days and the jet-lag would kill me, I rather stay up late here
14:13:45 [KjetilK]
Zakim, mute me
14:13:45 [Zakim]
kjetilk should now be muted
14:13:53 [bglimm]
I could probably organize some video conferencing here
14:14:47 [SimonS]
EricP: point of the meeting also is to interact with other groups, which means we need video conferencing on site, which is prohibitively expensive.
14:15:05 [SimonS]
LeeF: Unlikely that we will have video conferencing.
14:15:19 [SimonS]
... phone will be available, though.
14:15:57 [SteveH]
can we chivvy people to say whether they're going or not?
14:16:03 [SteveH]
I have to decide soon
14:16:09 [iv_an_ru]
Which Ivan?
14:16:13 [ericP]
nothing new from HCLS or XQuery
14:16:15 [SimonS]
topic: Liaisons
14:17:01 [SimonS]
Orri: nothing new from RDB2RDF
14:17:14 [AxelPolleres]
no news from RIF (teleconfs irregular, there is one today, so I will know more next week)
14:17:35 [SimonS]
Orri: talk about it at the F2F.
14:17:39 [LeeF]
open actions -
14:17:42 [SimonS]
topic: actions
14:17:52 [LeeF]
trackbot, close ACTION-66
14:17:52 [trackbot]
ACTION-66 Draft aggregates closed
14:20:07 [LeeF]
topic: Aggregates
14:20:09 [AxelPolleres]
71 is done from my side in the sense that rif and rdb2rdf are informed.
14:20:24 [LeeF]
draft of aggregate design at
14:21:29 [SimonS]
chimezie: First draft, some issues regarding sets vs multi-sets
14:21:39 [SimonS]
... do we need specific restrictions?
14:21:48 [SimonS]
... how to deal with DISTINCT?
14:21:55 [LeeF]
open issues at
14:22:22 [SimonS]
... seems we want to have variables associated with result of aggregates, so we always need AS
14:22:44 [SimonS]
... tried to describe algebra extension.
14:23:20 [SimonS]
... Start with groups function
14:23:56 [SimonS]
... starting with grouped variables.
14:24:39 [SimonS]
... function partitions takes solution set and extracts unique n-tuples, which are partitions of the solution set
14:24:51 [AxelPolleres]
q+ to ask about whether bnodes should be considered nasty or not
14:25:15 [LeeF]
ack ericp
14:25:16 [Zakim]
ericP, you wanted to talk about tech challenges re: vid conf
14:25:20 [SimonS]
... Aggregation then computes the actual aggregate.
14:25:29 [SimonS]
... now need test cases
14:26:21 [AxelPolleres]
ack me
14:26:21 [Zakim]
AxelPolleres, you wanted to ask about whether bnodes should be considered nasty or not
14:26:59 [ericP]
q+ to propose we stay with a graph semantics
14:27:02 [SimonS]
AxelPolleres: Are BNodes in the solution set an issue? e.g. count is difficult, if BNodes are treated as existentials
14:27:13 [SimonS]
... most implementations treat them as constants, though.
14:27:56 [bglimm]
I agrre in that blank nodes in our reasoner (OWL direct semantics) are not the same as constants
14:28:00 [SimonS]
Orri: We treat them as constants, sometimes owl:sameAs semantics is applied
14:28:06 [LeeF]
ack ericP
14:28:06 [Zakim]
ericP, you wanted to propose we stay with a graph semantics
14:28:26 [SimonS]
EricP: Language should stay a graph based language.
14:28:31 [AxelPolleres]
similar with "!=" which is currently "not known to be equal"
14:29:14 [SimonS]
LeeF: treat as in equals in filters
14:29:25 [SimonS]
... might need to look at this again for entailment regimes.
14:29:38 [LeeF]
ISSUE: How do other entailment regimes interact with aggregate grouping vis a vis blank nodes?
14:29:38 [trackbot]
Created ISSUE-34 - How do other entailment regimes interact with aggregate grouping vis a vis blank nodes? ; please complete additional details at .
14:30:25 [SimonS]
Orri: Guess, you can do expressions of aggregates
14:31:46 [LeeF]
for the record, extensibility of aggregate functions is an open issue
14:31:48 [SimonS]
... are user defined aggregates in scope, but we might need syntax restrictions?
14:32:18 [SimonS]
LeeF: we already have issue for extensions in aggregate functions
14:32:22 [ericP]
am fiddling with grammar (has S/R errors) --
14:32:22 [Zakim]
14:32:59 [Zakim]
14:33:08 [SimonS]
Zakim, ??P30 is me
14:33:08 [Zakim]
+SimonS; got it
14:33:46 [LeeF]
LeeF: can aggregate functions take multiple arguments?
14:34:00 [LeeF]
Chimezie: As long as all variables are part of gorup keys, should be ok, not sure if SQL aggregate functions do this at all
14:34:05 [LeeF]
Orri: there are a few like diverse_regression
14:34:37 [ericP]
ok, no S/Rs in
14:35:11 [SimonS]
chimezie; issues with multi sets. Do not require uniqueness. however, Aggregates do for partitioning.
14:35:49 [SimonS]
EricP: Algebra does not have ordering, but aggregates need them. Current algebra should work.
14:35:58 [SimonS]
Orri: Why do aggregates require ordering?
14:36:09 [SimonS]
EricP: Not always, but might make sense.
14:36:28 [chimezie]
SteveH did have an example on this SubSelect design wiki asking about ordering and aggregation (working together)
14:36:35 [chimezie]
14:36:35 [SimonS]
Orri: For user defined aggregates we have a flag for that, but usually it is not neccessary.
14:36:58 [SimonS]
... should not be an issue, if we do not specify extension syntax
14:37:18 [LeeF]
14:37:35 [SimonS]
iv_an_ru: also benefits for parallelization then.
14:37:51 [chimezie]
Zakim, who is here?
14:37:51 [Zakim]
On the phone I see kasei (muted), LeeF, SteveH, AlexPassant, john-l, AxelPolleres, kjetilk (muted), Orri, LukeWM, bglimm, Chimezie_Ogbuji, Prateek, iv_an_ru, EricP, SimonS
14:37:55 [Zakim]
On IRC I see Prateek, chimezie, bglimm, SimonS, KjetilK, Zakim, RRSAgent, LukeWM, AxelPolleres, SteveH, LeeF, karl, john-l, iv_an_ru, kjetil, AlexPassant, trackbot, kasei, ericP
14:38:20 [SimonS]
LeeF: do we need test case, that needs ordering?
14:38:30 [SimonS]
EricP: same as for SubSelect.
14:38:48 [SimonS]
LeeF: Last week we had consensus to discard ordering for subqueries.
14:39:12 [SimonS]
Orri: ORDER BY allowed?
14:39:37 [SimonS]
LeeF: yes, needed for slicing for example, but when combined with parent query, order is lost.
14:40:07 [SimonS]
LeeF: what specific aggregate functions to include?
14:40:10 [AxelPolleres]
any slicing in subqueries potentially introduces non-determinism, but well, I guess that was discussed?
14:40:17 [SimonS]
... discuss tios on the mailing list.
14:40:19 [ericP]
chimezie, do you know of a grammar proposal for SELECT ?foo AS ?bar which i could inject tinot the SPARQL_Aggregate grammar?
14:40:46 [SimonS]
LeeF: How to apply REDUCED / DISTINCT? Afterwards?
14:41:04 [SimonS]
chimezie: if done afterwards, everything should be fine.
14:41:05 [ericP]
ahh, it was in your proposal
14:41:14 [SimonS]
Orri: grouped columns are distinct anyway.
14:42:01 [SimonS]
Orri: Can we have DISTINCT in aggregate expressions?
14:42:16 [SimonS]
14:42:33 [LeeF]
ISSUE: Can aggregate functions take DISTINCT as an argument a la SELECT COUNT(DISTINCT ?X)?
14:42:33 [trackbot]
Created ISSUE-35 - Can aggregate functions take DISTINCT as an argument a la SELECT COUNT(DISTINCT ?X)? ; please complete additional details at .
14:42:55 [LukeWM]
q+ to ask about HAVING
14:43:13 [LeeF]
ack LukeWM
14:43:13 [Zakim]
LukeWM, you wanted to ask about HAVING
14:43:34 [SimonS]
LukeWM: does HAVING cause issues?
14:43:43 [SimonS]
Orri: HAVING is save.
14:44:02 [SimonS]
... can be done in nested query.
14:44:06 [LeeF]
14:44:43 [kasei]
we had talked earlier about using FILTER instead of HAVING (not introducing new terms for roughly the same thing)
14:44:53 [SteveH]
yes, reusing FILTER would makesense
14:45:06 [SimonS]
chimezie: should be easy to add to the proposal for completeness' sake.
14:45:46 [LeeF]
ACTION: Chimezie to continue forward with aggregates w.r.t test cases, HAVING/FILTER clause, ISSUE-35, ...
14:45:46 [trackbot]
Created ACTION-79 - Continue forward with aggregates w.r.t test cases, HAVING/FILTER clause, ISSUE-35, ... [on Chimezie Ogbuji - due 2009-08-18].
14:46:23 [LeeF]
topic: service description
14:47:22 [LeeF]
14:47:26 [SimonS]
LeeF: Most important question is discovery mechanism. We hava >= 8 proposals.
14:47:42 [SimonS]
14:48:54 [SimonS]
... drop proposal 3 - Well known location.
14:49:02 [SimonS]
... general agreement on this.
14:49:23 [SimonS]
... drop 5 - Query as well.
14:49:31 [AxelPolleres]
is "DESCRIBE <.>" also meant as a suboption of Opt 4?
14:49:42 [SimonS]
... EricP likes it, but noone else.
14:50:32 [SimonS]
... some objections to 6: prefer discovery via the endpoint instead of via the query.
14:52:07 [ericP]
chimezie, shows that your example query works with the grammar you supplied (modulo AggregateFunc which I added)
14:52:16 [SimonS]
... issue with option 7 without conneg is that existing implementations might have webpages at endpoint URI
14:52:38 [SimonS]
... proposal 8: do get with some special operation
14:52:43 [chimezie]
ericP: thanks
14:53:00 [ericP]
feel free to fiddle with the grammar
14:53:10 [ericP]
(note [Edit this grammar])
14:53:11 [SimonS]
... is anyone NOT happy with using an approach based on the endpoint rather than the query?
14:53:18 [kasei]
14:53:56 [kasei]
Zakim, unmute me
14:53:56 [Zakim]
kasei should no longer be muted
14:54:10 [SimonS]
EricP: might be nice to be able to query endpoint descriptions, but could solve that differently.
14:54:46 [AxelPolleres]
14:54:47 [SimonS]
LukeWM: favors conneg
14:54:53 [LeeF]
14:55:08 [LukeWM]
14:55:17 [kasei]
Zakim, mute me
14:55:17 [Zakim]
kasei should now be muted
14:55:21 [LeeF]
ack AxelPolleres
14:55:34 [SimonS]
AxelPolleres: What was objection to option 4?
14:55:53 [SimonS]
LeeF: restricts possible datasets and URIs
14:55:59 [kasei]
and that describe doesn't always return the same things...
14:56:02 [ericP]
q+ to ask how i find for instance, what VoID description it has in opt 4
14:56:21 [SimonS]
LeeF: same for DESCRIBE <> as it is just a shortcut
14:56:28 [LeeF]
ack ericP
14:56:28 [Zakim]
ericP, you wanted to ask how i find for instance, what VoID description it has in opt 4
14:57:12 [SteveH]
you can still do FROM <endpoint> .... on stores that support it
14:57:13 [SimonS]
EricP: that also means optimization becomes more difficult than just serving a void description.
14:57:39 [SimonS]
Orri: You would usually ask for the whole graph once.
14:58:20 [SimonS]
EricP: imagine void, void* etc, so guessing the best representation is a burden on the endpoint
14:59:36 [SimonS]
Orri: don't want to do many round trips with lots of short queries. Retrieve full description once, then do postprocessing locally.
14:59:59 [SimonS]
EricP: But we might be interested in certain aspects of the description only.
15:00:09 [AxelPolleres]
q+ to ask about the relative or absolute description in the protocol based options
15:00:22 [kasei]
ericP's point, I think, supports conneg or a simple GET mechanism so that you *could* point a SPARQL query at the SD if you wanted.
15:00:24 [LeeF]
zakim, close the queue
15:00:24 [Zakim]
ok, LeeF, the speaker queue is closed
15:01:01 [SimonS]
Orri: We might say in the viod description that the description is queryable, and where.
15:01:07 [SimonS]
15:01:24 [LeeF]
ack AxelPolleres
15:01:24 [Zakim]
AxelPolleres, you wanted to ask about the relative or absolute description in the protocol based options
15:02:07 [SimonS]
AxelPolleres: option 1 is just about returning a link to the service description, i.e. two GETs are neccessary, while the others are one GET only.
15:02:13 [SimonS]
LeeF: that is right.
15:02:32 [AxelPolleres]
2 GETs for getting to the service description seems a bit awkward to me, personally.
15:02:59 [LeeF]
PROPOSED: Service description discovery should be based on an operation performed against a SPARQL endpoint, ruling out options 3,4,5,6 in
15:03:51 [AxelPolleres]
need to get something clear: does it mean we agree that QUERYING the service description should NOT necessarily be allowed on the very endpoint?
15:04:02 [Zakim]
15:04:22 [SimonS]
I'd say not required.
15:04:43 [SteveH]
to be convinced I'd need to be shown that it works, not that it meets some usecases
15:05:03 [SimonS]
EricP: Could do use cases for querying. Would that be worth while?
15:05:13 [SteveH]
you can still do FROM <endpoint> .... on stores that support it
15:05:30 [SimonS]
Orri: Propose to include in the endpoint based description link to the queryable version
15:06:18 [kasei]
option 7 gives you queryability for free with a FROM clause.
15:07:03 [SimonS]
LeeF: discussion closed, please continue on the mailing list. Continue discussion next week
15:07:10 [LeeF]
ACTION: Orri to send a compromise proposal to the mailing list
15:07:11 [trackbot]
Created ACTION-80 - Send a compromise proposal to the mailing list [on Orri Erling - due 2009-08-18].
15:07:44 [Zakim]
15:07:44 [LeeF]
15:07:46 [Zakim]
15:07:53 [LukeWM]
15:07:55 [Zakim]
15:07:56 [SteveH]
15:07:57 [Zakim]
15:07:57 [Zakim]
15:07:58 [Zakim]
15:07:59 [Zakim]
15:08:00 [Zakim]
15:08:00 [Zakim]
15:08:02 [Zakim]
15:08:06 [Zakim]
15:08:10 [Zakim]
15:08:20 [LeeF]
15:08:26 [LeeF]
(how to do the minutes)
15:08:39 [Zakim]
15:08:47 [Zakim]
15:08:51 [Zakim]
SW_(SPARQL)10:00AM has ended
15:08:52 [Zakim]
Attendees were +1.518.276.aaaa, kasei, LeeF, LukeWM, +1.207.735.aabb, SteveH, SimonS, AlexPassant, john-l, AxelPolleres, Orri, bglimm, kjetilk, Chimezie_Ogbuji, Prateek,
15:08:54 [Zakim]
... +, EricP, iv_an_ru
15:26:44 [SimonS]
minutes are available at
15:26:48 [SimonS]
15:26:51 [SimonS]
SimonS has left #sparql
15:28:16 [AxelPolleres]
AxelPolleres has left #sparql
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AxelPolleres has joined #sparql
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