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Re: "Connection is still name resolving, can't reuse" error

From: Leo Song via curl-library <curl-library_at_cool.haxx.se>
Date: Tue, 2 Jun 2020 09:08:05 -0700

@Daniel Stenberg <daniel_at_haxx.se> Thank you for the reply.

1. The way I am using cURL and share the pool is via AWS S3 SDK.
Threads are sharing one static "m_curlHandleContainer" that gets created in
my application. And the SDK has its own mechanism to protect from
synchronization issue.
https://github.com/aws/aws-sdk-cpp/blob/master/aws-cpp-sdk-core/source/http/curl/CurlHttpClient.cpp#L498

Do you think this way of sharing connection essentially doing the same as
my previous approach with connection cache sharing (CURLSH)?

2. Yes. I tried disabling the header by setting CURLOPT_EXPECT_100_TIMEOUT_MS
to 0, and the 100-continue did not occur. I am just not sure if this is
going to cause any side effect, even though I have not seen any yet.

3. Yes. I am trying to provide an example code excluding the AWS S3 SDK
that can reproduce the symptom. I am a bit new to cURL, so this may take
some time.

Thanks again for your help!

Best,

On Mon, Jun 1, 2020 at 11:44 PM Daniel Stenberg <daniel_at_haxx.se> wrote:

> On Mon, 1 Jun 2020, Leo Song wrote:
>
> > Instead of connection cache, I have implemented a custom class that
> allows
> > multiple threads to share the connection pool, it seems working OK
> except a
> > few thing.
>
> How does it share this pool? I will again point to
> https://github.com/curl/curl/issues/4915
>
> > With this new change, I am now starting to get "Expect: 100-continue",
> which
> > makes it wait for a server response for 1 second. This slows down my
> > application, so I've set CURLOPT_EXPECT_100_TIMEOUT_MS to 1ms.
>
> That seems pointless. Why not disable the header completely instead?
>
> > I am sure my new change with the connection pool is causing this
> > 100-continue because without this change, no 100-continue occurred.
> However,
> > I have been struggling to pinpoint why/what is really causing this
> > "100-continue"
>
> Then you better explain clearly and with details what you did. Maybe share
> an
> example code that can reproduce?
>
> --
>
> / daniel.haxx.se | Commercial curl support up to 24x7 is available!
> | Private help, bug fixes, support, ports, new features
> | https://www.wolfssl.com/contact/
> 

-- 
Best regards,
Kyung Joon Song.

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Received on 2020-06-02