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Re: Easy Reuse across Multiple Multi Handles

From: Daniel Stenberg via curl-library <curl-library_at_cool.haxx.se>
Date: Thu, 30 Jul 2020 12:11:02 +0200 (CEST)

On Wed, 29 Jul 2020, Damon Earp via curl-library wrote:

> In the past few months we moved from v7.61.1 to v7.67.0, which is why I
> looked at that briefly. Anecdotally it looks like the newer version of
> libcurl is causing more single use connections than the older version. But
> as I said, I haven't done a full analysis to determine if that's true.

Things that will impact the behavior that you didn't mention (or perhaps I
missed it):

Parallelism - if you add 100 easy handles to a multi handle, they will be done
mostly in parallel and thus they can't reuse connections.

CURLMOPT_MAX_HOST_CONNECTIONS will limit the parallelism and will libcurl
rather queue transfers internally if you reach the host name limit.

You didn't say how many different host names you're using nor how many
transfers in parallel you're doing - but since you refer to the connection
cache being full, then I think that you simply run into connection pool size
issues perhaps because you use a large number of host names.

If you think this is due to some actual problem or bug in libcurl, then I
would need more specific instructions on how to reproduce.

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Received on 2020-07-30