Re: Socket server

Hi Scott,

This server/worker has been originally written some
time ago and enhanced during these years. Now - apart
from the mysterious crash - is stable and efficient.

The server handles more than 400,000 rqs per day, and
is used to retrieve lists and pdf documents from
optical disks. This retrieval is very fast for recent
documents but can take a lot of time for old ones.
That's why the worker can be busy for 10-15 seconds.
Furthermore, because the client runs on a
internet/intranet browser, very often the impatient
user presses the cancel button and click again on the
document, thus starting another worker !

The dtaq approach - as you pointed out - has some
advantages, but I will try to play with the snd/rcv
method, just in case ...

Giuseppe.

--- Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx> ha
scritto:

Hi Beppe,

But I don't understand how the server can know if
there is a worker available or they are all busy

and a

new one should be started and then passed the

request.

Good question.

Personally, I use a spawning server (or INETD) when
I expect to handle
requests that will take a long time. In a
long-running request, the
start-up time is not usually significant, so
pre-starting the workers
isn't much of an issue.

I use pre-started worker jobs only when I expect to
handle requests that
are relatively short, and therefore it's okay to
queue up a few
connection attempts.

I suppose the server could maintain an array of
workers and keep track
of the status of each one. Each time a worker
accepts a new connection,
it notifies the server by sending information via a
socket or pipe.
That give you a scenario very similar to the data
queue you're using
now... the problem with that scenario is it slows
down the speed at
which the server can accept new connections. Which
is why I just use a
spawning server in that scenario, if the accept
speed is going to be
slow ANYWAY, what's the advantage of having a pool
of server jobs?

But, perhaps the data queue approach is the best way
for you, at least
for the time being.

One more question: the worker is in recvmsg.

However

if no request arrives within say 30 minutes, it

should

end. Shall I use alarm to set the timeout ?

alarm() or select(), just like any other socket.
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