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Replicating memes From the mind of Philip

Replicating memes From the mind of Philip
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Why do you need Tracker?

Replicating memes From the mind of Philip - Fri, 05/07/2013 - 11:11pm
(Or why our project’s name wasn’t wrong after all) First and foremost, because the Internet isn’t available everywhere all the times. To put it simple: 3G (and 4G) suck. The latency is a joke in even the most modern countries, and even their capital cities. Reliable availability of The Internet simply doesn’t exist for most [...]

A use-case for SPARQL and Nepomuk

Replicating memes From the mind of Philip - Mon, 24/06/2013 - 9:23pm
As I got contacted by two different companies last few days who both had questions about integrating Tracker into their device, I started thinking that perhaps I should illustrate what Tracker can already do today. I’m going to make a demo for the public transportation industry in combination with contacts and places of interest. Tracker’s [...]

Bypassing Tracker’s file system miner, for example for MTP daemons

Replicating memes From the mind of Philip - Mon, 17/12/2012 - 11:49am
Recapping from my last blog article; I worked a bit on this concept during the weekend. When a program is responsible for delivery of a file to the file system that program knows precisely when the rename syscall, completing the file transfer transaction, takes place. An example of such a program is an MTP daemon. [...]

Warming up

Replicating memes From the mind of Philip - Fri, 14/12/2012 - 2:19pm
Hey former Harmattan peeps. How about we do a little bit of this Jolla stuff after our hours and see where it goes? You never know, and neither have any of the technologies and improvements that we did for Nokia harmed us. It’s at #jollamobile on FreeNode. Btw. Ping me if you are going to [...]

Morals? Forbidding stuff?

Replicating memes From the mind of Philip - Mon, 10/12/2012 - 12:21pm
It isn’t freedom to have to choose for Richard Stallman’s world view. It isn’t ‘freedom’ to be called immoral just because you choose another ethic. It isn’t freedom when a single person or group with a single view on morality tries to forbid you something based on just their point of view. For example, Stallman [...]

Allowing local cults of personality in open source

Replicating memes From the mind of Philip - Sat, 10/11/2012 - 2:10pm
Hey Aaron. I mostly agree with your post. I don’t fully agree, however, with “We needed Android because we couldn’t do it ourselves”: Mostly Qt (and also KDE) developers, and some GNOME developers who where still left developing for Nokia since the N900 and earlier, made the Nokia N9 Swipe phone. Technically the product is [...]

Curiosity

Replicating memes From the mind of Philip - Mon, 06/08/2012 - 5:10am
Up early to follow EDL of Curiosity. Follow it live here. Go NASA! Edit ‘We are on Mars again. Photo of a wheel and a shadow of the rover’:

How I think companies like Jolla should do it

Replicating memes From the mind of Philip - Mon, 09/07/2012 - 12:07pm
I’ll focus on the technical stuff; I think I would only Peter Principle myself if I would try giving management advice. What I’ve seen too much are community projects, companies or groups who think that the synchronization of Harmattan with Moblin or MeeGo was done well to make what is now the OS on the [...]

Battery drain on N9 caused by a combination of Battery-Icon, Tracker and Smartsearch

Replicating memes From the mind of Philip - Thu, 05/07/2012 - 3:11pm
Tired of the fact that my N9 had few battery time I decided to “as a developer” investigate my device a little bit. Last time I did that I was still contracted by Nokia and a few days later I had to fly to Helsinki to help fix a Tracker in combination with contactsd bug. [...]

Avoiding duplicate album art storage on the N9

Replicating memes From the mind of Philip - Thu, 18/08/2011 - 7:20am
At Tracker (core component of Nokia N9‘s MeeGo Harmattan’s Content Framework) we extract album art out of music files like MP3s, and we do a heuristic scan in the same directory of the music files for files like cover.jpg. Right now we use the media art storage spec which we at a Boston Summit a few years [...]

Null support for INSERT OR REPLACE available in master

Replicating memes From the mind of Philip - Mon, 15/08/2011 - 10:26am
About Last week I wrote about adding a feature to our SPARQL Update’s INSERT OR REPLACE. With that feature it’s not needed to put a DELETE upfront the INSERT to clear a field. This makes our SPARQL-ish INSERT OR REPLACE in some ways more powerful than SQL’s UPDATE. Note, however, that all of INSERT OR [...]

Support for null with Tracker’s INSERT OR REPLACE feature.

Replicating memes From the mind of Philip - Tue, 09/08/2011 - 9:38am
I believe it was the QtContacts Tracker team who requested this feature. When they have to unset the value of a resource’s property and at the same time set a bunch of other properties, they need to use a DELETE statement upfront an INSERT OR REPLACE. The DELETE increases the amount of queries and introduces [...]

Refactoring our writeback system

Replicating memes From the mind of Philip - Thu, 14/07/2011 - 10:15pm
Tracker writes back certain metadata to your files. It for example writes back in XMP the title of a JPeg file, among other fields that XMP supports. We had a service that runs in the background waiting for signals coming from the RDF store that tell it to perform a writeback. To avoid that our [...]

The ever growing journal problem

Replicating memes From the mind of Philip - Mon, 11/07/2011 - 2:55pm
Current upstream situation In Tracker‘s RDF store we journal all inserts and deletes. When we replay the journal, we replay every event that ever happened. That way you end up in precisely the same situation as when the last journal entry was appended. We use the journal also for making a backup. At restore we [...]

We delivered

Replicating memes From the mind of Philip - Wed, 22/06/2011 - 10:46pm
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 [...]

INSERT OR REPLACE explained in more detail

Replicating memes From the mind of Philip - Fri, 25/03/2011 - 4:30pm
A few weeks ago we were asked to improve data entry performance of Tracker’s RDF store. From earlier investigations we knew that a large amount of the RDF store’s update time was going to the application having to first delete triples and internally to the insert having to look up preexisting values. For this reason [...]

A REPLACE extension for Tracker’s SPARQL’s Update

Replicating memes From the mind of Philip - Wed, 09/03/2011 - 5:02pm
SPARQL Update has INSERT and DELETE. To update an existing triple in RDF you need to DELETE it first. You of course already have our INSERT-SILENT but that just ignores certain errors; it doesn’t replace triples. A (performance) problem is that with each DELETE having to solve all possible solutions you create an extra query [...]

Synchronizing your application’s data with Tracker’s RDF store

Replicating memes From the mind of Philip - Mon, 31/01/2011 - 4:36pm
A few months ago we added the implicit tracker:modified property to all resources. This property is an auto-increment. It used to be that the property was incremented on ~ each SQL update-query that happens. The value is stored per resource. We are now changing this to be per transaction. A transaction in Tracker is one [...]

All quiet on the Tracker front

Replicating memes From the mind of Philip - Wed, 26/01/2011 - 12:49pm
It has been a long time since we wrote propaganda about the Tracker project. That has a lot to do with both the holiday-season and the fact that we’re preparing for a stable release. This means that we are increasingly reluctant to new features. We still made quite some progress, though. We for example ported [...]

IPC performance improvements for insert queries

Replicating memes From the mind of Philip - Fri, 08/10/2010 - 3:45pm
Although with SQLite WAL we have direct-access now, we don’t support direct-access for insert and delete SPARQL queries. Those queries when made using libtracker-sparql still go over D-Bus using Adrien’s FD passing D-Bus IPC technique. The library will do that for you. After investigating a performance analysis by somebody from Intel we learned that there [...]

LRU cache for prepared statements in Tracker’s RDF store

Replicating memes From the mind of Philip - Wed, 22/09/2010 - 4:45pm
While trying to handle a bug that had a description like “if I do this, tracker-store’s memory grows to 80MB and my device starts swapping”, we where surprised to learn that a sqlite3_stmt consumes about 5 kb heap. Auwch. Before we didn’t think that those prepared statements where very large, so we threw all of [...]

Less exciting features also need to be done, return types

Replicating memes From the mind of Philip - Thu, 09/09/2010 - 3:29pm
We have a feature request to support return types and to give back variable names. We currently return an array (of array) of just strings, with no typing. This doesn’t work very well for knowing whether a cell is (for example) unbound. Empty string isn’t the same as unbound. So what can you do? With [...]

Tracker’s new class signal system being developed

Replicating memes From the mind of Philip - Tue, 24/08/2010 - 10:49pm
Tracker 0.8′s situation In Tracker 0.8 we have a signal system that causes quite a bit of overhead. The overhead comes from: Having to store the URIs of the resources involved in a changeset in tracker-store‘s memory; Having to store the predicates involved in a changeset in tracker-store‘s memory (less severe than A because we […]

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

Replicating memes From the mind of Philip - Wed, 11/08/2010 - 1:01pm
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 […]

Domain indexes finished, technical conclusions

Replicating memes From the mind of Philip - Wed, 07/07/2010 - 10:30am
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 . […]

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