On Tue, Jun 13, 2006 at 10:36:27PM -0400, Tom Lane wrote: > * not clear whether the interrupt happens when waiting for I/O. I > already mentioned that this would be a problem for EXPLAIN ANALYZE, > but it might be no big deal for the other uses.
If we're going y UNIX signal semantics, in theory any interruptable function (as listed on the signal manpage) would be interrupted every N milliseconds to handle the interrupt. So yes, if possible the interrupt will be serviced anyway, even during I/O, by aborting a restarting the I/O continuously. Not terribly efficient. With one big exception: sometimes I/O is non-interruptable (the good old D state). In this case the interrupts will happen but will simply be queued and in fact will all be dropped except the last one (non-realtime signals are never stacked). The handler will probably be called the moment it returns to user-space. Note: Do we want SIGPROF, SIGALRM or SIGVTALRM? There's apparently a distinction, see: http://en.wikipedia.org/wiki/SIGPROF Have a nice day, -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > From each according to his ability. To each according to his ability to > litigate.
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