Have bernhard attempt to set SO_REUSEADDR.#24
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On an app with heavy TCP traffic, this will minimize the use of extra TCP IP/port pairs.
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I'm not following the need here. Why is your app creating and tearing down clients with any frequency? |
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My app is not, any longer. An older revision of it was. That said: If you have any process opening and closing TCP client sockets quickly to a given server (say, your DB), if you are not using SO_REUSEADDR you will fail to connect to the remote end due to port exhaustion. The root cause is port exhaustion due to sockets in TCP TIME_WAIT state. On a linux system with default TCP stack settings you have roughly 16384 available ephemeral ports (per destination address), and your defaut TIME_WAIT timeout is two minutes. That roughly means that you can trigger port exhaustion in this situation with as few as 136 connections/sec. Varnish, nginx, and haproxy are examples of applications which could easily trigger this situation. Setting SO_REUSEADDR on client connections mitigates this by allowing port number/ip address combinations to be reused before that timeout in certain situations. |
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On an app with heavy TCP traffic, this will minimize the use of extra
TCP IP/port pairs.