In message <[log in to unmask]>, Bruce Toback
<[log in to unmask]> writes
>Roy Brown writes:
>
>>In practice, you might see more conditional lock failures, due to longer
>>lock periods from the queued unconditionals. But this would only occur
>>if you had defects in your locking strategy to begin with.
>
>Why would queued locks be a sign of a defective locking strategy?
>
Sloppy writing on my part, alas. I think it's what you said, only you
said it better :-)

I meant that if you had a locking strategy that didn't recover too well
when a conditional lock was refused, you might not notice this under
normal circumstances, where locks weren't held for very long.

But with unconditional locks queuing up, a record is effectively held
locked, with no respite, for as long as it takes for all the requests to
be serviced.

Like if I want my hair cut, I'll walk past the barber's, and if there's
a chair free, I'll go in and have it done. Works fine if everyone does
that, and/or the load is not too high.

But once people start forming a queue there, and the traffic is such
that there is never a free chair when I go by, I will find my hair
growing way too long.

I will need a new strategy if I am ever to get my locks shorn....
--
Roy Brown               Phone : (01684) 291710     Fax : (01684) 291712
Affirm Ltd              Email : [log in to unmask]
The Great Barn, Mill St 'Have nothing on your systems that you do not
TEWKESBURY GL20 5SB (UK) know to be useful, or believe to be beautiful.'