>>>>> "Tom" == Tom Lane <tgl@sss.pgh.pa.us> writes:
Tom> AFAIK, no commercial database does predicate locking either,
True ..
Tom> so we all fall short of true serializability. The usual Tom> solution if you need the sort of behavior
you'retalking Tom> about is to take a non-sharable write lock on the table you Tom> want to modify, so that only
onetransaction can do the
Not really. If you have B+-tree indexes on the table you can get by
with key-value locking (as in ARIES/KVL) and achieve some of the
effects of predicate locking to get true serializability without
losing too much concurrency. While this falls short in the general
case, it turns out to be pretty acceptable normally (when indexes are
present).
--
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Sailesh
http://www.cs.berkeley.edu/~sailesh
