Re: TCP connections clogging up accf_http(9)

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

Ah thanks, I now understand.

So on the extreme ends, we have two scenarios leading to q0 overflow:
A) slow aggregation of dead connections
B) temporary overload
(If you omit "slow" from A or "temporary" from B, you're in trouble.)

With A, it's fine to move an old entry from q0 to q and attach the new one 
to q0.
With B, it's best to drop the new connection attempt; probably drop parts 
of q0, too.

Couldn't the size of q (at least after exercising the "A" solution for a 
short while) be taken to tell between the two? I.e. accept old/queue new 
if q is empty, drop new (and drop parts of q0) if q is full?
A connection burst would then initially be mistaken as a slow aggregation 
(q0 full, q empty), but only until the "wrong" decision to accept would fill 
q too, which would then automatically switch to the appropriate behaviour.