[ZODB-Dev] design issue: job queue is concurrency bottleneck
Toby Dickenson
tdickenson at geminidataloggers.com
Thu Mar 4 09:49:53 EST 2004
On Thursday 04 March 2004 05:04, John Belmonte wrote:
> I finally got through the first round of concurrency testing on my app.
> Despite being a high-write application, virtually no write conflicts
> occur-- with one major exception. I have a job queue, which is a BTree
> keyed by scheduled job time. It's the only BTree in my app that doesn't
> have random keys. Incoming requests to my server tend to generate a few
> jobs, and unfortunately they must be scheduled at various constant time
> periods in the future. As a result, simultaneous requests generate jobs
> scheduled for approximately the same time, mapping to the same area of
> the BTree, and causing write conflicts.
That makes sense for keys that are *exactly* the same time. For approximately
the same time then surely conflict resolution would take care of the write
conflict?
Or do you have read conflicts?
--
Toby Dickenson
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