Scrap baloo?

[Boudhayan Gupta]

Hi,

On 16 September 2016 at 01:04, Christoph Cullmann <cullmann at absint.com> wrote:
>>> => Opinions?
>>
>> It would be nice to hear what Vishesh, Pinak and Boudhayan think about
>> this.

I prefer getting familiar with the code as well as having a mile-high
view of what does what before I start laying down code, hence why I
haven't submitted a single line of code yet. What I have been doing so
far, though...

I've been trying to track down the history of Baloo and which part
does what. Also looking at past backends and what decisions were taken
that ended up with Baloo in the state that it is today.

I spoke to Pinak privately and he's volunteered to write some
documentation over the weekend. I've also been looking at why Baloo
doesn't use something like Xapian (which is made for use-cases like
Baloo) and I was pointed to this:
https://community.kde.org/Baloo/XapianProblems. Looks like the whole
rationale boils down to - we have so much custom code over Xapian we
might as well just have custom code over LMDB instead, it's faster.

I have a long journey (an actual journey, flights, buses, the whole
deal) ahead of me and I'll have some time to think about a long-term
plan for Baloo. It may involve killing it and working against Tracker,
or it may even involve putting more custom code into it. Whatever the
decision is, I'm going to try and justify the effort involved before I
present my plan to everyone here.

So far I'm leaning towards either a safer wrapper around LMDB or a
custom Key Value Database (basically a reimplimentation of Bitcask in
C++) for which we can ensure the presence of a Qt-friendly "safe" C++
API, to armour the database code. I actually think Baloo in its
current form is very well designed; for example, using the filesystem
as a database is pure genius. It's just sloppily executed and the code
quality could do with... some work.

I think wrapping the Database bits into a more modular and reusable
component was part of Vishesh's plans anyway, because other bits of
KDE would like to re-use them.

Anyway, enough rambling. I should have something in a few days.

Thanks,
Boudhayan