[tahoe-dev] use case request for accounting/leasedb

[Zooko Wilcox-O'Hearn]

Okay, great! I was very confused to think that querying and changing
leases would be a long expensive process. That's the whole *point* of
leasedb is to make that fast and reliable. Duh.

I agree that the protocol you sketched out in your email would work,
including that the client can wait for confirmation that it worked and
retry it if it didn't (such as if the server failed at any point).

It kind of sounds like with this current revision of the scheme you
don't really need to crawl over all the shares for the purpose of
garbage collection. You still need to crawl in order to build an index
of shares for the first time (i.e., when you first turn on leasedb, or
if your leasedb gets destroyed or corrupted) and even if you have a
leasedb, you might still want to crawl in order to discover
externally-imported shares, and I *guess* it might be useful to crawl
in order to discover that shares have been externally removed, but
there's no need to crawl in order to expire or garbage-collect shares,
is there?

If that's right, maybe we shouldn't run a crawler all the time and
support adding shares by simply copying them into place and waiting
for a crawler to discover them.

Regards,

Zooko