[Seaside] ImageSegments as persistence
avi at dabbledb.com
Mon Feb 19 20:59:07 UTC 2007
On 2/19/07, Sebastian Sastre <ssastre at seaswork.com> wrote:
> Avi did you have any progress on that primitive that you want for array
> allocation to disk?
No. I'm still interested in it if anyone has time.
> I understood is file based and not atomical (transactional) and that it
> is like a piece of the image in another file.
It's certainly atomic in that there is a single primitive that builds
the segment. But you'll need to do a lot of work yourself to get the
ACID properties you might want.
> How much can one rely on them? any experience in production
Once a segment is successfully built, I've never had any trouble
loading one into a new image (and Dabble DB has produced god knows how
many hundreds of thousands of image segments by this point). The
problems are in building them - you have to be *very* careful not to
have any outpointers, and the allocation of the buffer to build the
segment can cause low-memory conditions more often than I'd like
(hence the desire for the disk-based version).
> I think, that if reliable, it is an interesting option for seaside
> applications that do not require transactions.
If you understand and can carefully manage them, they certainly are.
But they're hardly an "out of the box" persistence solution.
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