De dierentuin: geboortebeperking versus slachten

Michel Vandenbosch versus Dirk Draulans: ben ooit zo’n 15 jaar vegetariër geweest om vandaag tevreden te zijn over dit goed voorbereid en mooi gebalanceerd debat. Mijn dank aan de redactie van Terzake.

Ik was het eens met beide heren. Daarom was dit een waardig filosofische discussie: geboortebeperking versus het aan de leeuwen voeden van overbodige dieren plus het nut en de zin van goed gerunde dierenparken. Dat nut is me duidelijk: educatie voor de dwaze mens (z’n kinders, in de hoop dat de opvolging minder dwaas zal zijn)

Hoewel ik het eens was met beide ben ik momenteel zelf meer voor het aan de leeuwen voeden van overbodige dieren dan dat ik voor geboortebeperking van wel of niet bedreigde diersoorten ben. Dat leek me, met groot respect voor Vandenbosch’s, Draulans’ standpunt te zijn. Ethisch snapte ik Vandenbosch ook: is het niet beter om aan geboortebeperking te doen teneinde het leed van een slachting te vermijden?

Ik kies voor het standpunt van Draulans omdat dit het meeste de echte wereld nabootst. Ik vind het ook zeer goed dat het dierenpark de slachting van de giraffe aan de kinderen toonde. Want dit is de werkelijkheid. Onze kinderen moeten de werkelijkheid zien. We moeten met ons verstand de werkelijkheid nabootsen. Geen eufemisme zoals het doden van een giraffe een euthanasie noemen. Laten we onze kinders opvoeden met de werkelijkheid.

Maalwarkstrodon

It’s a mythical beast that speaks in pornographic subplots and maintains direct communication with your girlfriends every wants and desires so as better to inform you on how to best please her. It has the feet of bonzi buddy, the torso of that man who uses 1 weird trick to perfect his abs, and the arms of the scientists that hate her. Most impressively, Maalwarkstrodon has a skull made from a Viagra, Levitra, Cialis, and Propecia alloy. This beast of malware belches sexy singles from former east-bloc soviet satellite states and is cloaked in the finest fashions from paris and milan, imported directly from Fujian china.

Maalwarkstrodon is incapable of offering any less than the best deals at 80% to 90% off, and will not rest until your 2 million dollar per month work-at-home career comes to fruition and the spoils of all true nigerian royalty are delivered unto those most deserving of a kings riches.

Maalwarkstrodon will also win the malware arms race.

De monarchie van’t land

Ik ben niet noodzakelijk voorstander van de of een monarchie. Maar wanneer het goed is, is het goed. De redacteurs van de VRT hebben zeker moeite gedaan een positief beeld te schetsen in Koppen. Maar zelfs moest ik moeite doen negatief te zijn, kan ik niets slechts vinden in het beeld dat men vandaag van koning Filip schetste. Ik ben tevreden dat iemand met zorg en zorgzaamheid met België en de Belgen bezig is.

RE: Scudraketten

Wanneer Isabel Albers iets schrijft ben ik aandachtig. Misschien ben ik verliefd? Misschien is ze een verstandige vrouw? Niettemin doe ik moeite me te ontdoen van m’n eigen grote waarheden. Één blijft overeind: wij moeten investeren in infrastructuur.

Dit creëert welvaart, distribueert efficiënt het geld en investeert in onze kinderen hun toekomst: iets wat nodig is; en waar we voor staan.

De besparingsinspanningen kunnen we beperken wat betreft investeringen in infrastructuur; we moeten ze des te meer doorvoeren wat betreft andere overheidsuitgaven.

Misschien moeten we bepaalde scudraketten lanceren? Een scudraket op de overheidsomvang zou geen slecht doen.

Een week mediastorm meemaken over hoe hard we snoeien in bepaalde overheidssectoren: laten we dat hard en ten gronde doen.

Laten we tegelijk investeren in de Belgische infrastructuur. Laten we veel investeren.

Rusland

De cultuur die heerst, leeft,  ploert en zweet op het grondgebied van Rusland zal niet verdwijnen. Zelfs niet na een nucleaire aanval tenzij die echt verschrikkelijk wreedaardig is. En dan zou ik ons verdommen dat we dat gedaan hebben zoals ik hoor te doen. Wij, Europeanen, moeten daar mee leven zoals zij met ons moeten leven.

We delivered

Damned guys, we’re too shy about what we delivered. When the N900 was made public we flooded the planets with our blogs about it. And now?

I’m proud of the software on this device. It’s good. Look at what Engadget is writing about it! Amazing. We should all be proud! And yes, I know about the turbulence in Nokia-land. Deal with it, it’s part of our job. Para-commandos don’t complain that they might get shot. They just know. It’s called research and development! (I know, bad metaphor)

I don’t remember that many good reviews about even the N900, and that phone was by many of its owners seen as among the best they’ve ever owned. Now is the time to support Harmattan the same way we passionately worked on the N900 and its predecessor tablets (N810, N800 and 770). Even if the N9’s future is uncertain: who cares? It’s mostly open source! And not open source in the ‘Android way’. You know what I mean.

The N9 will be a good phone. The Harmattan software is awesome. Note that Tracker and QSparql are being used by many of its standard applications. We have always been allowed to develop Tracker the way it’s supposed to be done. Like many other similar projects: in upstream.

As for short term future I can announce that we’re going to make Michael Meeks happy by finally solving the ever growing journal problem. Michael repeatedly and rightfully complained about this to us at conferences. Thanks Michael. I’ll write about how we’ll do it, soon. We have some ideas.

We have many other plans for long term future. But let’s for now work step by step. Our software, at least what goes to Harmattan, must be rock solid and very stable from now on. Introducing a serious regression would be a catastrophe.

I’m happy because with that growing journal – problem, I can finally focus on a tough coding problem again. I don’t like bugfixing-only periods. But yeah, I have enough experience to realize that sometimes this is needed.

And now, now we’re going to fight.

Support for SPARQL IN and NOT IN, the new class signals

I made some documentation about our SPARQL-IN feature that we recently added. I added some interesting use-cases like doing an insert and a delete based on in values.

For the new class signal API that we’re developing this and next week, we’ll probably emit the IDs that tracker:id() would give you if you’d use that on a resource. This means that IN is very useful for the purpose of giving you metadata of resources that are in the list of IDs that you just received from the class signal.

We never documented tracker:id() very much, as it’s not an RDF standard; rather it’s something Tracker specific. But neither are the class signals a RDF standard; they are Tracker specific too. I guess here that makes it usable in combo and turns the status of ‘internal API’, irrelevant.

We’re right now prototyping the new class signals API. It’ll probably be a “sa(iii)a(iii)”:

That’s class-name and two arrays of subject-id, predicate-id, object-id. The class-name is to allow D-Bus filtering. The first array are the deletes and the second are the inserts. We’ll only give you object-ids of non-literal objects (literal objects have no internal object-id). This means that we don’t throw literals to you in the signal (you need to make a query to get them, we’ll throw 0 to you in the signal).

We give you the object-ids because of a use-case that we didn’t cover yet:

Given triple <a> nie:isLogicalPartOf <b>. When <a> is deleted, how do you know <b> during the signal? So the feature request was to do a select ?b { <a> nie:isLogicalPartOf ?b } when <a> is deleted (so the client couldn’t do that query anymore).

With the new signal we’ll give you the ID of <b> when <a> is deleted. We’ll also implement a tracker:uri(integer id) allowing you to get <b> out of that ID. It’ll do something like this, but then much faster: select ?subject { ?subject a rdfs:Resource . FILTER (tracker:id(?subject) IN (%d)) }

I know there will be people screaming for all objects, also literals, in the signals, but we don’t want to flood your D-Bus daemon with all that data. Scream all you want. Really, we don’t. Just do a roundtrip query.

Domain indexes finished, technical conclusions

The support for domain specific indexes is, awaiting review / finished. Although we can further optimize it now. More on that later in this post. Image that you have this ontology:

nie:InformationElement a rdfs:Class .

nie:title a rdf:Property ;
  nrl:maxCardinality 1 ;
  rdfs:domain nie:InformationElement ;
  rdfs:range xsd:string .

nmm:MusicPiece a rdfs:Class ;
  rdfs:subClassOf nie:InformationElement .

nmm:beatsPerMinute a rdf:Property ;
  nrl:maxCardinality 1 ;
  rdfs:domain nmm:MusicPiece ;
  rdfs:range xsd:integer .

With that ontology there are three tables called “Resource”, “nmo:MusicPiece” and “nie:InformationElement” in SQLite’s schema:

  • The “Resource” table has ID and the subject string
  • The “nie:InformationElement” has ID and “nie:title”
  • The “nmm:MusicPiece” one has ID and “nmm:beatsPerMinute”

That’s fairly simple, right? The problem is that when you ORDER BY “nie:title” that you’ll cause a full table scan on “nie:InformationElement”. That’s not good, because there are less “nmm:MusicPiece” records than “nie:InformationElement” ones.

Imagine that we do this SPARQL query:

SELECT ?title WHERE {
   ?resource a nmm:MusicPiece ;
             nie:title ?title
} ORDER BY ?title

We translate that, for you, to this SQL on our schema:

SELECT   "title_u" FROM (
  SELECT "nmm:MusicPiece1"."ID" AS "resource_u",
         "nie:InformationElement2"."nie:title" AS "title_u"
  FROM   "nmm:MusicPiece" AS "nmm:MusicPiece1",
         "nie:InformationElement" AS "nie:InformationElement2"
  WHERE  "nmm:MusicPiece1"."ID" = "nie:InformationElement2"."ID"
  AND    "title_u" IS NOT NULL
) ORDER BY "title_u"

OK, so with support for domain indexes we change the ontology like this:

nmm:MusicPiece a rdfs:Class ;
  rdfs:subClassOf nie:InformationElement ;
  tracker:domainIndex nie:title .

Now we’ll have the three tables called “Resource”, “nmo:MusicPiece” and “nie:InformationElement” in SQLite’s schema. But they will look like this:

  • The “Resource” table has ID and the subject string
  • The “nie:InformationElement” has ID and “nie:title”
  • The “nmm:MusicPiece” table now has three columns called ID, “nmm:beatsPerMinute” and “nie:title”

The same data, for titles of music pieces, will be in both “nie:InformationElement” and “nmm:MusicPiece”. We copy to the mirror column during ontology change coping, and when new inserts happen.

When now the rdf:type is known in the SPARQL query as a nmm:MusicPiece, like in the query mentioned earlier, we know that we can use the “nie:title” from the “nmm:MusicPiece” table in SQLite. That allows us to generate you this SQL query:

SELECT   "title_u" FROM (
  SELECT "nmm:MusicPiece1"."ID" AS "resource_u",
         "nmm:MusicPiece1"."nie:title" AS "title_u"
  FROM   "nmm:MusicPiece" AS "nmm:MusicPiece1"
  WHERE  "title_u" IS NOT NULL
) ORDER BY "title_u"

A remaining optimization is when you request a rdf:type that is a subclass of nmm:MusicPiece, like this:

SELECT ?title WHERE {
  ?resource a nmm:MusicPiece, nie:InformationElement ;
            nie:title ?title
} ORDER BY ?title

It’s still not as bad as now the “nie:title” is still taken from the “nmm:MusicPiece” table. But the join with “nie:InformationElement” is still needlessly there (we could just do the earlier SQL query in this case):

SELECT   "title_u" FROM (
  SELECT "nmm:MusicPiece1"."ID" AS "resource_u",
         "nmm:MusicPiece1"."nie:title" AS "title_u"
  FROM   "nmm:MusicPiece" AS "nmm:MusicPiece1",
         "nie:InformationElement" AS "nie:InformationElement2"
  WHERE  "nmm:MusicPiece1"."ID" = "nie:InformationElement2"."ID"
  AND    "title_u" IS NOT NULL
) ORDER BY "title_u"

We will probably optimize this specific use-case further later this week.