when does apache write to the access log?

If a given GET/POST is not recorded in access_log, does this guarantee
that apache did not receive the incoming request on the network side?
Or does apache delay writing to access_log until the underlying module
(e.g. mod_php) returns? The second scenario would suggest that
absence of an access_log record could be due either to a problem
before apache received the request, or within the called module.
Thanks.

"chipk" <ckaye9@gmail.com> wrote in message
news:a14f844e-d256-46b3-89bf-75ab64288ce5@p25g2000hsf.googlegroups.com...
> If a given GET/POST is not recorded in access_log, does this guarantee
> that apache did not receive the incoming request on the network side?
> Or does apache delay writing to access_log until the underlying module
> (e.g. mod_php) returns? The second scenario would suggest that
> absence of an access_log record could be due either to a problem
> before apache received the request, or within the called module.
> Thanks.

Apache only writes the log entry upon completion of the request (one of the
standard fields in the log is the number of bytes transferred, which will
not be known until the end of the request)

You may want to look into mod_status and the ExtendedStatus directive.