On 26 Aug, 11:08 pm, clay.gerr...@rackspace.com wrote: >The way that sqlalchemy implements pool_recycle is "irrespective of >idle time" best I can tell from looking at it. Keeping track of the >last_used_time seems like it would have been equally reasonable, >although perhaps even additional overhead.
It probably wouldn't be much more overhead. The important question to consider is whether SQLAlchemy (and whoever else) had another good reason for doing it the way they do it. Is monitoring idle time not sufficient for some systems? > >I'm not sure I understand what you mean by "parameterize the reactor" - >pass it as an argument when you initialize the (Re)ConnectionPool? Can >you point me to a twisted class that does this as an example? Yep, that's what I meant. You can find examples of this in some of the newer code in Twisted (as we only started to encourage it relatively recently). One example is twisted.web.wsgi.WSGIResource; another is twisted.internet.task.deferLater. > >I agree it would be very cool "to do the reconnecting more proactively >in idle threads" - I'll have to think on that, do you know off-hand of >any analogs? Hm. I can't think of any analogs, no. I hope the implementation would be straightforward, though. The connection pool can use reactor.callLater in the main thread to force old connections to be re- established, and it can take those connections out of the lineup while it's doing that, to make sure no queries are dispatched to them. One tricky part, though, may be ensuring that a connection isn't actively servicing a query when time comes to recycle it. The thread pool used by the connection pool may not currently have the features required for this (it doesn't allow messages to be directed at specific threads, for example). This feature may also not be terribly important. I don't know what the reconnect overhead actually is. Jean-Paul _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
