On Fri, 3 Oct 2003, Avleen Vig wrote:
> To work around file locking contention against the filesystem-based db.
> This is a big problem on high-throughput relays.
That is a concern, yes, but
(1) If messages are not being delayed, there are only read accesses to
the hints databases. These do not hold up other processes, because they
use shared locks. One way to make use of this fact is to use fallback
hosts, so that delayed messages are not kept on the high-throughput
relays, but on some backup relays. If you do that, there will never be
any writes to the hints databases on the high-throughput relays. And
what's more, searching an empty hints file will be pretty quick. :-)
(2) As has been said already, you should optimize disk hardware
performance (e.g. by putting hints on RAM disk, etc.)
(3) I can't see how using SQL can be *that* much better, in that it too
must use some kind of locking feature in order to handle simultaneous
accesses. Can it really do this in a more efficient way than the
system's file locking? There also has to be a process switch (as far as
I know) in order to interact with an SQL database.
I'm just skeptical, but I'm not an expert in this stuff, so I accept
that I may be wrong...
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
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