Daniel Stenberg wrote:
> Hi friends,
>
> multi interface users of libcurl, this issue may concern you so please
> bare with my longish mail and I'll get to the point eventually...
>
> I visited a company yesterday (who's name is left here since it isn't
> important to this dicussion) that is using libcurl quite heavily and I
> got to debug libcurl when used by an application simulating hundreds of
> clients, each doing tens of requests.
>
> These guys of course use the multi_socket API but it turns out at times
> it seemed to "forget" connections (which caused a hang). It turned out
> to be an existing (7.19.7) bug in libcurl and it happened like this:

I've had similar problems with the multi_socket API, but I think this
behaviour goes back beyond 7.19.7.

To verify I get you right:
------
curl_multi_add_handle()
  -> CURLMOPT_TIMERFUNCTION 1ms

Timeout ->
do {
    res = curl_multi_socket_action(... TIMEOUT ...);
} while(CURLM_CALL_MULTI_PERFORM == res);

connection state INIT -> CONNECT

CONNECT does not register a timeout, or sockets, the handle is stale.
------

If there are multiple handles on the multi, some new timeout from other
handles would resurrect the stale handle?

> If you've read this far and have an idea of what I've tried to say, I'd
> say you're qualified to have an opinion on the matter so please tell me
> what you think or if I've missed some detail or whatever.

I'm not sure if I got the point correctly, I understand the A fix
intention, but I doubt it will change things.

I've had the same 'problem' with the multi_socket interface, but the
problem was a stale handle after successful connect, afaik the handle
would be 'revived' once other handles got active, and removed for some
timeout conditions.

Markus
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Received on 2010-01-31