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libcurl and TCP connection setup rate control

From: gerwsx via curl-library <curl-library_at_lists.haxx.se>
Date: Fri, 30 Sep 2022 15:11:32 +0200

Hello,

Does anyone know if there is a way to control the TCP connection setup rate?

When there are a lot of requests to be sent, libcurl keeps opening TCP
connections with a very high rate, for example:

./myfile.log:3408916:* 17:34:58.365097 * STATE: CONNECT => WAITCONNECT
handle 0xe83c8008; line 1481 (connection #11)
./myfile.log:3408926:* 17:34:58.365561 * STATE: CONNECT => WAITCONNECT
handle 0xe83c9408; line 1481 (connection #12)
./myfile.log:3408956:* 17:34:58.366233 * STATE: CONNECT => WAITCONNECT
handle 0xc1e5c008; line 1481 (connection #13)
./myfile.log:3408966:* 17:34:58.366703 * STATE: CONNECT => WAITCONNECT
handle 0xd9115408; line 1481 (connection #14)
./myfile.log:3408976:* 17:34:58.367160 * STATE: CONNECT => WAITCONNECT
handle 0xd9768808; line 1481 (connection #15)
./myfile.log:3408986:* 17:34:58.367656 * STATE: CONNECT => WAITCONNECT
handle 0xaf8b0008; line 1481 (connection #16)
./myfile.log:3408996:* 17:34:58.368084 * STATE: CONNECT => WAITCONNECT
handle 0xe4a7b408; line 1481 (connection #17)
./myfile.log:3409006:* 17:34:58.368475 * STATE: CONNECT => WAITCONNECT
handle 0xe8ead408; line 1481 (connection #18)
./myfile.log:3409016:* 17:34:58.368865 * STATE: CONNECT => WAITCONNECT
handle 0xa8f73408; line 1481 (connection #19)
./myfile.log:3409026:* 17:34:58.369277 * STATE: CONNECT => WAITCONNECT
handle 0xc9c73408; line 1481 (connection #20)
./myfile.log:3409037:* 17:34:58.369716 * STATE: CONNECT => WAITCONNECT
handle 0xe8574008; line 1481 (connection #21)
./myfile.log:3409047:* 17:34:58.370128 * STATE: CONNECT => WAITCONNECT
handle 0xb5f2c008; line 1481 (connection #22)
./myfile.log:3409057:* 17:34:58.370522 * STATE: CONNECT => WAITCONNECT
handle 0xbcb18008; line 1481 (connection #23)
./myfile.log:3409067:* 17:34:58.370895 * STATE: CONNECT => WAITCONNECT
handle 0xb8a02808; line 1481 (connection #24)

etc.

We have limited resources available and the TCP connection setup is
slow. Is there a way to let libcurl back off for a while before opening
a new TCP connection?

Thanks

ger

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Received on 2022-09-30