Hi Shane, > On 11/07/2011 03:15 PM, Darryl Dixon - Winterhouse Consulting wrote: >> Hi All, >> >> We have just converted a site with a handful of editors over from ZEO to >> RelStorage on Oracle and and the rate of ConflictErrors has gone through >> the roof (5 an hour average continuously for days). [...snip...] >> Currently we are using a very basic >> RelStorage configuration without any additional bits like memcache. >> > I have a few thoughts: > > - You aren't using poll-interval, are you? Make sure that is disabled. > > - When you switched from ZEO to Oracle without turning on memcache, you > lost the ZEO cache and didn't replace it with anything, so now loading > objects takes longer, which may lead to more conflicts. I would try > turning on memcache. > > - Do you have multiple storages / databases? Make sure each uses a > different Oracle lock ID.
We are not using the poll-interval, so clear on that one. I wasn't clear that memcache would assist in this situation - I will see about enabling it in this environment, but there are a few questions I need a better understanding for with this around what exactly are the characteristics of memcache integration: * What is the situation with using multiple memcache instances (eg, one per machine - will this lead to cache incoherency - inconsistency between instances, etc? * What is the failure scenario for a memcache instance dying - is it handled gracefully by RelStorage or will there be hanging/blocking/tracebacks until it returns? * Will this potentially exacerbate the ancient ZEO-Client-Race condition that occurs with load-balancing when data changes? (To be clear, I am referring to when one Zope instance updates/commits some data, and then the client browser makes a new request which is directed to a second Zope instance, which has not yet received an invalidation message for the changed objects, and it returns, eg, a 404 to the client). Any guidance on the above once again very gratefully received. With regards the the commit lock - yes, we use multiple storages and each uses a different commit-lock-id. Thanks heaps for your help, regards, Darryl Dixon Winterhouse Consulting Ltd http://www.winterhouseconsulting.com _______________________________________________ For more information about ZODB, see http://zodb.org/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
