I have a question about the caching of MySQL
connections by Exim.
Our main use of MySQL is for username verific-
ation. A CDB is built on a regular basis and
that is queried first, but the database is
queried directly if the user is not found in the
CDB - to cover the case where a customer
exists, but is not yet in the CDB.
This also has the effect of causing a lot of
database lookups when there is an incoming
spam of the aaaaaa@??? thru zzzzz@domain
.com variety.
My question is, in which process does the
verification of an address take place. I see
there is code in lookups/mysql.c for caching
MySQL connections. However, we have observed that
the number of MySQL processes increases on the
server during an incoming spam.
I assume that the caching applies on a per exim
process basis; and that, if the verification
does not occur in the daemon process, this would
be the cause of the additional mysql processes
on the database server.
So, the question is, how do I go about limiting
the number of database connections that Exim will
open? Not very easily, I guess is the answer, if
it is not the daemon that is doing the verifica-
tion.
Perhaps this will be easier in Exim 4?
Thanks.
Ollie
--
Oliver Cook Systems Administrator, ClaraNET
ollie@??? 020 7903 3000 ext. 291
