listen_backlog
Backlog (queue size of pending connections) of the listen socket. The default value of<4096> is the same as that of linux 5.4+).
Usually this value does not need to be changed, since:
- The default value is large enough,
- For accepting client’s connections server has separate thread.
<TcpExtListenOverflows> (from <nstat>) non-zero and this counter grows for ClickHouse server it does not mean that this value needs to be increased, since:
- Usually if
<4096>is not enough it shows some internal ClickHouse scaling issue, so it is better to report an issue. - It does not mean that the server can handle more connections later (and even if it could, by that moment clients may be gone or disconnected).
listen_host
Restriction on hosts that requests can come from. If you want the server to answer all of them, specify::.
Examples: