_conn_req_max_q Parameter

Description

Specifies the default maximum number of pending TCP connections for a TCP listener waiting to be accepted by accept. See also _conn_req_max_q0 Parameter.

Default

128

Range

1 to 4,294,967,295

Dynamic?

Yes

When to Change

For applications such as web servers that might receive several connection requests, the default value might be increased to match the incoming rate.

Do not increase the parameter to a very large value. The pending TCP connections can consume excessive memory. Also, if an application cannot handle that many connection requests fast enough because the number of pending TCP connections is too large, new incoming requests might be denied.

Note that increasing _conn_req_max_q does not mean that applications can have that many pending TCP connections. Applications can use listen to change the maximum number of pending TCP connections for each socket. This parameter is the maximum an application can use listen to set the number to. Thus, even if this parameter is set to a very large value, the actual maximum number for a socket might be much less than _conn_req_max_q, depending on the value used in listen.

Commitment Level

Unstable