[Zope] Zope 2.8 and conflict errors

[Maciej Wisniowski]

> It might. ZEO adds network overhead to ZODB transactions,
> which generally increases the likelihood of conflict errors.

I've created ZEO and executed the same test 
with my application.

Tests were done with SQLRelay backend (DCOracle2 is 
running now ;))

I have tested this with 50, 55, 60 and 70 users.
with 50 users: no 'HTTP/1.1 500' errors
with 55 users: no 'HTTP/1.1 500' errors
with 60 users: no 'HTTP/1.1 500' 1 error for 1800 urls requested
with 65 users: no 'HTTP/1.1 500' 4 errors for 1950 urls requested

All errors are with OOBTree and as I can see 
with tempstorage.TemporaryStorage. They look like:

<li>  Module ZPublisher.Publish, line 187, in publish_module_standard</li>
<li>  Module ZPublisher.Publish, line 161, in publish</li>
<li>  Module ZPublisher.Publish, line 161, in publish</li>
<li>  Module ZPublisher.Publish, line 161, in publish</li>
<li>  Module ZPublisher.Publish, line 151, in publish</li>
<li>  Module Zope2.App.startup, line 158, in zpublisher_exception_hook</li>
<li>  Module ZPublisher.Publish, line 119, in publish</li>
<li>  Module Zope2.App.startup, line 215, in commit</li>
<li>  Module transaction._manager, line 84, in commit</li>
<li>  Module transaction._transaction, line 381, in commit</li>
<li>  Module transaction._transaction, line 379, in commit</li>
<li>  Module transaction._transaction, line 424, in _commitResources</li>
<li>  Module ZODB.Connection, line 462, in commit</li>
<li>  Module ZODB.Connection, line 503, in _commit</li>
<li>  Module ZODB.Connection, line 526, in _store_objects</li>
<li>  Module tempstorage.TemporaryStorage, line 200, in store</li>
</ul>ConflictError: 
database conflict error (oid 0x0944, class BTrees._OOBTree.OOBTree, 
serial this txn started with 0x035f134dc11a2977 2005-08-03 12:29:45.258327, serial 
currently committed 0x035f1357051c7199 2005-08-03 12:39:01.197916)


So far I see that DCOracle2 version of my app caused 9 errors for 
the same scenario with 50 users. These are conflict errors with 
DCOracle2.DA.Procedure and in ZEO.ClientStorage...

-- 
Maciej Wisniowski