[ZODB-Dev] RelStorage: Clearing temp_store in replication-friendly way

[Stephan Richter]

On Thursday 24 July 2008, Shane Hathaway wrote:
> > P.S.: I am quite excited about the memcached support. Does it "just  
> > work"? I.e. can I run my ZODB in RAM now? ;-)
>
> I expect the new memcache support to be safe for everyone to use, but we
> still require the main database to be connected at all times, since
> memcache provides no ACID properties by itself.  We unfortunately can't
> do obvious things like cache the current transaction ID for an object,
> since that would break MVCC.  What we do cache is:
>
> 1. The current tid, given an oid and the transaction ID that is active
> for the current connection.
>
> 2. The pickle given an oid and tid.
>
> These should both help read-heavy databases, but might be detrimental
> for write-heavy databases.  My performance test suite, which writes a
> lot, produced slightly *worse* results with memcache enabled.

We should get Brian Aker into this discussion, since is one of the main 
architects of MySQL and one of the founders of memcached.

As Shane knows, I have some access to Brian these days, so we could have an 
online meeting talking about it.

Regards,
Stephan
-- 
Stephan Richter
Web Software Design, Development and Training
Google me. "Zope Stephan Richter"