[Monodevelop-devel] Using SQLite as parser database

["Andrés G. Aragoneses"]

Hi. Just my 2 cents on this.

Mike Krüger wrote:
> Hi
>
>   
>> This discussion should have been done before committing anything to
>> trunk, but here it is anyway.
>>
>> Migrating to SQLite only makes sense if it provides noticeable
>> improvements in performance and memory use. Guessing that it will be
>> better is not enough. We need real numbers before taking the decision
>> to
>> switch, and only do it if the numbers are so much better that pay off
>> the burden of having a dependency on SQLite.
>>
>> I might be wrong, but I don't believe that SQLite will be better than
>> the ad-hoc database we are using in MD 1.0. I spent a lot of time
>> tuning
>> up the parser database, and I'm quite happy about how is it
>> performing.
>>
>>     
>
> Some more benefits for using a real database over an own implementation:
>
> - It's reliable. Atomic transactions, threading - all solved.
> - It's easy to look into the data using a command line client and SQL
> statements
>
> Its not just pure performance. Using a database will allow us for
> example to switch the database software to a new implementation. And
> databases and SQL are very easy to understood and to change.
>
> I had to think about it too (I implemented the #develop database some
> years ago which monodevelop inherited (but optimized I admit ^^)) -
> after thinking about it the decision was easy - A database makes it
> easier to change the model and to make complicated querys more
> efficient. 
>
> There are many more reasons using database software instead of own data
> storage solutions - otherwise the whole database software would be
> obsolete.
>   

There are a lot of reasons too why programs don't use SQL database 
software. Maintainability gets hurt also by adopting such a solution in 
a OOP world; I guess you have heard about the Impedance mismatch [1], 
hence the existance of complicated ORM [2] frameworks or OOP databases 
like DB4O [3] (which in particular could be a better bet, but I guess 
the license is not adequate for MD).

I'm also worried about the fact that your opinion about SQLite may be 
biased because I guess you only used Win32 OS when you were working in 
SharpDevelop, right? There has been huge performance problems (locking 
problems) with SQLite in Linux, which recently caused a lot of 
discussions due to its usage in Firefox (which BTW is performing for me 
a lot worse than other browsers in Linux). I can't give you the exact 
reference of where I read (but I can give you some first google hits 
like [4] and [5]) it but AFAIK this is yet a problem to be solved 
upstream (don't remember if it's in the kernel or in the extX filesystem).

Regards,

    Andrés

[1] http://en.wikipedia.org/wiki/Object-Relational_impedance_mismatch
[2] http://en.wikipedia.org/wiki/Object-relational_mapping
[3] http://www.db4o.com/
[4] 
http://digg.com/linux_unix/Firefox_3_has_system_killing_performance_problem_for_Linux
[5] 
http://news.softpedia.com/news/Who-Freezes-The-System-Firefox-or-ext3-86242.shtml
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