Update: no Gmail integration after all, feel free to contact me if you want to help

Hi all,

I already teased publicly about the new Gmail resource on Google+ yesterday, now it's time for some more explanations and...screenshots!

What is this about?

A native Gmail Resource for Akonadi that will bring much better integration of Gmail features into Kmail.

I've been talking about it and promising it for quite some time. But now thanks to some changes to the regular IMAP Resource that Christian Mollekopf has done recently, I could finally start working on it!

But...why?

Those who use Gmail know that Gmail does some things differently than most normal mail services. The biggest difference is that there are not really any folders with emails. Instead there's one folder with all your emails and then there are labels, that you can assign to emails and then you can just filter your emails by the labels. And you can assign multiple labels to one email.

Yeah, but why bother? It already works quite well with the normal IMAP resource, right?

Yes, Gmail is able to hide this specialities from regular email clients so that they can still work with Gmail like with any other generic mail server, but at the cost of losing some features.

More and more often you can hear today that desktop email clients are dead and the future is in webmail (and cloud). And for many users who only have one email account this is true - why having KMail and KOrganizer etc. running, when they can have all this and more opened constantly in a single tab in their web browser? And the truth is, that Gmail is simply the largest mail provider in the world today. So if we want to persuade all these users to keep using KMail, we need to provide a user experience that is as close as possible to the native web interface. And for that we need a native Akonadi Resource ;-)

(Note: I'd like to avoid flamewars about "desktop clients are not dead vs. are dead" - I believe they are not dead for people who use more than one email account. They will cling to desktop clients until the dawn of the Gods, and even longer, but for normal users with just one mail account, it might be just matter of years to leave desktop clients. But who knows. impossible to see the future is).

Ok, so what's the difference between Gmail and IMAP Resources?

The Gmail Resource supports some Gmail-specific IMAP extensions. In other words, it can speak and understands Gmail's IMAP dialect. This means that the Gmail resource can handle the Gmail specifics better than the generic IMAP Resource:

1) Flattened folder hierarchy. This is best shown on screenshots: on the left, there's a folder hierarchy as shown in KMail when using the current IMAP resource, on the right there's the same account but synced via the new Gmail resource.

2) One email to rule them all! As explained above, one email on Gmail can have multiple labels. But when you sync the mail via normal IMAP, you get a copy of that email in each folder. That means, that marking the mail as read will only mark as read that copy, but not the other copies in other folders, simply because KMail does not know they are effectively the same mail.

The Gmail resource is aware of this, an it syncs all your emails into one hidden folder and then just links them to the actual folders representing Gmail labels that you can see in KMail, so when you mark an email as read in any folder, it will mark it as read in all folders it's linked into. Awesome, right?

3) OAuth authentication. The regular IMAP resource only supports the regular username-password authentication (and GSSAPI), which means that your password is stored in the computer somewhere, and if you use 2-step verification, you need to generate an app-specific password.

The Gmail resource has support for Gmail's OAuth2, so you only enter your password once into Google's web login, and the resource will then use a special tokens issued by Gmail with limited life-span to authenticate all your requests.

The authentication is actually powered by LibKGAPI, a Qt/KDE library that implements various Google APIs, so it has the same look and uses the same code as the Akonadi Resources for Google Calendars and Google Contacts.

(Funny story and a question: I actually had to write a custom plugin for Cyrus-SASL to support XOAUTH2 mechanism, as upstream does not support it. Does anyone know whether there's an existing implementation somewhere on the interwebs that I could use instead my crappy plugin?)

4) Simpler configuration. This is not really that big, bacause you don't open the dialog very often, but I really like the configuration dialog a lot: simple and without complex options like encryption, mechanisms... This is simply because Gmail supports only a specific set of IMAP features, so I could just remove lot's of stuff from the configuration dialog making it thinner and much easier to understand (IMO).

5) Push-notifications for all folders. The IMAP Resource can only monitor one folder for changes (using IMAP IDLE), because of certain technical restrictions. The folder usually is the Inbox. So if you have server-side filtering, you will never get push-notifications about new emails arriving to your other folders.

The limitation for watching only one folder applies to the Gmail Resource too. However since we understand Gmail, we can watch the "All Mail" folder, instead of the Inbox, so this way we get push notifications about emails from absolutely all folders (except for Trash and Junk folders, but who cares about these). Thinking about it, I could even remove the "Check Interval" option from configuration now.

Uhm ok, so what's the state of the resource?

Currently the resource is still in a branch, waiting for some more features to be finished and for Christian to approve some of my changes to the IMAP resource (I'll bribe him with some beer during Akademy, if necessary ;-)), and some changes must be done in KMail to properly support copying and moving of the linked emails, but other than that, it already works quite nicely :-)

That's about it, see you next time :-)

Hi KMail users,

we have a little favor to ask from you :-) On the KDE PIM Sprint we discussed how to improve email threading in KMail by using Akonadi to store the information, so that KMail does not have to compute it every time. This would make opening a folder almost instant, all threads would be reconstructed immediately and it would massively improve CPU and memory consumption (so it's totally something worth helping us with ;-)) More details on what else we discussed and implemented will follow in another blog post tomorrow.

To implement the threading caching, we need to know, whether in these days it still makes sense to support threading by Subject. It's used as a fallback when grouping by standardized email headers (In-Reply-To, References) are missing, which used to be a case with buggy email clients years ago, but hopefully is better now, so we could drop it, which would massively simplify the algorithms.

So we would like you to disable threading by Subject, observe how much it breaks your threading (and potentially your workflow) and report back to us. To disable it, go to View ->Message List ->Aggregation -> Configure. There go to Groups & Threading tab and in Threading combobox select Perfect and by Reference. If the combo boxes are disabled, you have to click Clone Aggregation to clone the default settings, and use the clone.

View->Message List->Aggregation->Configure...

Aggregation Configuration

If removing threading by subject would break threading and workflow for too many users, we will keep the settings and we will try to figure out another way to do it.

So please configure your KMails, and let us know in comments below this post, on IRC, kde-pim mailing list or through any other communication means (just please try to avoid using smoke signals and pigeons ;-))

Thank you for your help!

Akonadi 1.10.3 has been released, fixing (among other things) support for PostgreSQL 9.2 with Qt 4.8.5.

I write a blog specially about this update, because the fix requires updating the Akonadi database schema. The update will be performed on next Akonadi start and it can take some time, especially on larger databases, so we kindly ask users for patience.

Update: if your distribution ships Qt 4.8.5 with the PSQL driver patch reverted, please make sure to remove the revert before pushing Akonadi 1.10.3 to repositories.

Users of other backends (MySQL or SQLite) will not be affected by this update.

Big thank you for investigating and fixing this problem to Cédric Villemain.

Full changelog:

• Fix crash when there are no flags to update during flags change
• Fix crash on Akonadi shutdown when using PostgreSQL
• Fix notification to clients about database upgrade
• Send dummy requests to MySQL from time to time to keep the connection alive
• Bug #277839 - Fix problem with too long socket paths
• Bug #323977 - Check minimum MySQL version at runtime
• Bug #252120, Bug #322931 - Use text instead of bytea column type for QString in PostgreSQL

Thanks to Volker Krause, Christian Mollekopf and Cédric Villemain for their contributions to this release.

Hi!

I arrived back home from Akademy just a day ago and I already miss it. I enjoyed every single moment of it and had lots and lots of fun. Thanks everyone for making this such an awesome event, and especially to the local team. They did an incredible job!

This blog however will not be about Akademy (I will write one maybe later), but about Akonadi, core component of our PIM suite. As you probably already read or heard, Volker Krause has handed over to me maintainership of Akonadi.  It means really lot to me and I'll do my best to be at least as good maintainer as he was (if that's even possible) and I would like to thank him for his outstanding job he did writing and maintaining Akonadi.

I really believe in Akonadi, I like design of the framework and admire all the work guys have done on it since the beginning, long before I even dreamed about becoming a KDE contributor. I also believe that having a powerful and well-working PIM suite is the key for success of KDE (not just) in the enterprise world. Akonadi is more powerful than most of the competition out there, we just now need to focus bit more on stability and performance. I think we are doing pretty fine with stability, so I want to focus mainly on the performance side of Akonadi. In this bit more technical blog post I want to write about what I did recently, what I'm doing know and what are (some of) my future plans with Akonadi. As usually, huge thank you to Volker for his ideas, suggestions and comments about my ideas. We had a great discussion during Akademy and we (theoretically) solved many problems and bottlenecks that were bothering Akonadi for a long time, but nobody had time to look into it.

Batch Notifications

I started working on batch notifications after the KDE PIM sprint in March, merged it in May (I think) and hopefully have resolved all regressions by now. Akonadi server uses notifications to inform all clients about changes, like new items, changed items, removed items, etc. Notification is a simple data structure that is transferred via D-Bus to all clients. Before this patch there was one notification per each item which means that marking 500 emails as read had generated 500 notifications that had to be transferred via D-Bus. With batch notifications the server can create a single notification that references all 500 items. This saves a lot of D-Bus traffic and allows faster processing on the client side. This feature will be available in KDE 4.11.

MTime-based item retrieval

This was written during Akademy and will allow Vishesh to improve start-up time of the Akonadi Nepomuk Feeder. Until now the feeder had to fetch all items from Akonadi and all items from Nepomuk on start just to compare whether everything is up-to-date. With mtime-based item retrieval the feeder can ask Akonadi to hand over only items that have been changed since some given timestamp. In most cases that means 0 items. You have to agree that fetching no or just a few items instead of all of them will give us a notable performance boost during start. Albert allowed us to backport this to 4.11, so you will get this improvement in 4.11 as well.

External payload files without path

Another thing that has been implemented during Akademy is aimed to save some of your precious disk space. Because Akonadi is a cache for your data, it means that it has to store all your emails, contacts, events etc. somewhere. Smaller records are stored directly in the database. Larger items are stored in external files on your hard drive and there is only file path stored in the database. However the path is always the same and is usually around 50 characters long, while the file name is only around 10 characters long. This patch makes sure that only the file name without path is stored in the database, saving some disk space. Clients now also have the capability to understand file names without path in server replies, so we can even reduce size of traffic  between server and clients a bit. I know that 50 bytes is not much, but multiply it by tens or hundreds of thousands of items, and it's already worth it. As a side effect, all newly created databases will be relocatable, because all file paths are relative, not absolute. There is no plan to make an automated migration to strip the path from existing records, but I might one day implement this in the Janitor, so that users can migrate their database manually if they want to. But it's not a priority now.

Server-side monitoring

Previously I explained that Akonadi sends notifications via D-Bus to all clients to inform them about changes. The problem here is that not all clients are usually interested in all changes. For instance KOrganizer does not care about new emails and KMail does not care about modified appointments (there are exceptions like the Nepomuk Feeder, which listens to everything for obvious reason). Yet each notification is "broadcasted" to all Akonadi clients. Each client then decides whether it's are interested in the notification and wants to process it further or just drops it. The average number of clients is around 16, but in most cases only 3 or 4 clients are actually interested in each notification. That means that other 12 or 13 clients just drop the notification. What I'm working on right now is to move this filtering code to the Akonadi server, so that the clients can tell the server what kinds and types of notifications they want and the server will only send notifications to those clients that are really interested in it. This should save us a lot of D-Bus traffic and will fix the awkward situation when all clients are consuming CPU, even when you are just syncing one of your IMAP accounts.

Server-side change recording (IDLE)

The biggest task ahead of me. Some Akonadi clients are using feature called change recording. That means that every notification that is not dropped by the client is stored into a binary file (every client has one such file) and is removed again when the client confirms that the notification has been processed. This is used for example by the IMAP resource. When you are offline the resource is recording all notifications (about items being deleted, moved between folders, marked as read, etc) into the file and when you connect to the internet and the resource is switched to online all notifications are replayed from the file. My plan is to implement something similar to IMAP's IDLE. Changes will be recorded on the server instead of the clients and all clients will be able to connect to the server and request all pending notifications. After that they send "IDLE" command + explanation of what kind of notifications they are interested in and the server will automatically feed them with new notifications. This is essentially continuation of the "Server-side filtering" feature, but it takes it to a completely new level. With this feature the Akonadi framework will generated almost no D-Bus traffic at all and the whole thing will be much much faster. I'm really looking forward to work on this because it's a very challenging task and the result will definitely be worth the effort.

Volker has also submitted a few patches to reduce size of the messages sent between clients and server even more and started working on optimizing some SQL queries so that we don't query the database for data we don't actually use anywhere.

Of course there are more smaller ideas and improvements in the queue, but I need to keep something for next blog posts so stay tuned - there's more coming soon! :-)