Re: [Monotone-devel] mtn: error: sqlite error: database is locked

[Markus Schiltknecht]

Hi Chad,

Chad Walstrom wrote:
> How deep does the rabbit hole go?  Now we're getting into questions
> about whether or not the database should do work other than storing and
> retrieving data.  Personally, I'm not a fan of programming in-database,
> but there are times when it makes sense to do so.

Well, SQLite doesn't offer you much there. But for most other databases, 
I'd certainly recommend implementing as much of the logic as possible in 
a way the database understands. It saves you a lot of duplicate work and 
allows you to make full use of the very good optimizers of todays 
database systems. The more the database knows about your data, the 
better it can optimize queries.

> Obviously, the
> database cannot understand those higher-order objects, it's up to
> Monotone to draw meaning from them.  Likewise, it's up to Monotone to
> decide what is a safe transaction and an unsafe transaction relative to
> those objects.

That's certainly bogus. Source code can be equally clever, no matter if 
it's running within the database or not. I'd rather argue that lots of 
the logic would profit from a tight integration into the database.

> It's up to the database to make sure that the decisions
> Monotone makes become permanent, safely.

You are ignoring most of what todays databases offer. Take another look 
at the acronym ACID, only the last 'd' stands for durability.

> As it was stated earlier in
> this thread, making montone friendly to different types of transactions
> is going to take some API changes.

Sure. The question is, how to change it...

Regards

Markus