On Fri, Mar 08, 2013 at 11:24:25AM -0800, Quanah Gibson-Mount wrote: > >This is not a feature, it is a bug. OpenDKIM is a multi-threaded > >process that does not periodically exit to be replaced by a fresh > >process. As such it does not tolerate memory leaks in its own code > >or in the libraries it uses. > > OpenDKIM does what I ask. It makes a persistent connection and cuts > out the overhead of persistent rebinding.
Just because you want it, does not mean it is better. :-) > Thanks for pointing out max_use. Now instead of postfix rebinding > every 4-5 minutes to the LDAP servers, it is at least every 20 > minutes between binds, significantly cutting out startTLS > negotiation overhead and improving performance. > > It is trivial to see what a significant difference it makes in > postfix behavior to go from the default of 100 to 5000: > <http://www.pastebin.ca/2330089> It is surely trivial to see what an insignificant difference this makes. Between all those connections thousands of lookups are made, the connection overhead is negligible. The difference between a TLS handshake and LDAP bind every 4-5 minutes vs. every 20 minutes (or even infinity as with DKIM) is negligible. Almost all the payoff from re-use is in the first O(10) uses, after that it is diminishing returns all the way.... It is similar with max_use, it is of couse reasonably safe to have it higher than 100, but the benefit is marginal at best. -- Viktor.
