Re: [Bug-apl] A really simple component-file implementation

[Elias Mårtenson]

I think that I should probably implement SQL∆with_transaction. It belongs in the SQL layer. It's also the only way to ensure that transaction rollback on error is handled correctly.

Regards,

Elias

On 21 April 2014 12:18, David B. Lamkins <address@hidden> wrote:

One more code drop...

I've factored out the encode and decode routines to make it easier to
experiment with the storage format.

I've added a cf∆with_transaction operator to simplify transaction
support for applications that actually need it. This, I believe, is
useful since it lets the application determine policy for failed
transactions.

I've extended the test cases and performance tests.

One thing that's interesting is that cf∆append runs about twice as fast
inside the transaction wrapper than it does without. I imagine that
SQLite must be running several implicit transactions; these get deferred
by running the sequence of operations inside an explicit transaction.

Despite that observation, I'm loathe to build-in transaction support for
the sake of speed. It'd help the case where component files are
implemented on SQLite, but might not be the right thing to do for other
databases. Again, this is a policy decision that belongs at a higher
level of abstraction.