On Nov 16, 2005, at 6:18 PM, Dennis Allison wrote:
Chris,
I am aware that using ZEO to back session database is likely to increase the opportunity for conflicts, but using a single session database seems to be reaquired if you want, as we do, to distribute out interactive application acrosss a cluster of processors cleanly.
Under our current approach, we have multiple Zopes running on multiple machines, all referencing a shared database of session variables. This allows a HTTP request to be blindly distributed to any of the machines. Given the conflict problems, we may need to rethink this simplistic architecture.
Sure. The alternative solutions are: - "session affinity" load balancing solutions which always send the user to the same appserver instance across some number of requests based on a cookie value or the remote IP address. - session data manager implementations that don't use ZODB. Tres Seaver coded up a drop-in SDM implementation that used MySQL although I'm not sure that it was able to be released OSS at the time. A quick Google search doesn't turn up anything, so it's hard to tell. - C