This string defines the SQL query that logs the authentication
successes. It is an optional parameter and has no default value. You can
use special characters. For more information, see
Section 3.3. Special formatters. If it is not defined, accounting is
not logged at all.
The bind variables are replaced as
follows:
%0
: the result
%1
: the quoted reason string, usually this is
empty if successful
%2
: the SQL-quoted User-Name
%3
: the SQL-quoted original user name from the
incoming request (before any RewriteUsername rules were applied)
%4
: the tracing identifier string