|Subject||Re: [Firebird-Architect] event based nonblocking io|
> Perhaps the performance different between web servers is more aTrue. It's name - "a patchy server" - was well deserved, even when the
> reflection on the Apache than the underlying technique. Having written
> and maintained an Apache module for a decade, I must confess that is not
> my favorite piece of code...
code base was still young. As always, 'good enough' code arriving at the
right time gets ahead and even in open source it tends to be a 'winner
takes all' type of process.
> True, non-blocking IO does not equate to a single thread. But in aA recent post on high scalability is interesting in this area. Push
> multi-thread environment, many of the performance benefits of an event
> drive loop go away, and the application begins to look like fine grain
> multi-threading, with the concomitant cost in thread synchronization and
> context switches. I'm not arguing that fine grain multi-thread is not
> the way to go (Stonebreaker disagrees), just that multi-threading is
> more or less multi-threading.
services in mobile rely on maintaining many long lived connections with
little data going through (web sockets will change this, but for now its
long-polling). A service may have millions of waiting sockets. It turns out
that a current 64 bit machine can handle 500K simultaneous sockets using
non-blocking io and a callback/queuing event loop:
Interestingly, in a seperate blog post it is mentioned that using simple
tools (the Python "eventlets" non-blocking io + cooperative multi-threading
library written by Linden Labs for Second Life), they could operate well
over 30K sockets on a 32-bit amazon 'small' instance.
>> The question now is "how is this relevant to rdbms design?".Maybe it is all relevant for rdbms's driving mobile apps, with potentially
millions of simple, short-lived transactions coming in from the field. Even
then, I don't think we'll be in the 500K per machine range, as that can
only be done for sockets that are mostly idle and hence require very little