The redirect_children directive specifies how many redirector processes Squid should start. For example:
Squid warns you (via cache.log) when all redirectors are simultaneously busy:
WARNING: All redirector processes are busy.
WARNING: 1 pending requests queued.
If you see this warning, you should increase the number of child processes and restart (or reconfigure) Squid. If the queue size becomes twice the number of redirectors, Squid aborts with a fatal message.
Don’t attempt to disable Squid’s use of the redirectors by setting redirect_children to 0. Instead, simply remove the redirect_program line from squid.conf.