[ZODB-Dev] My turn for ReadConflictErrors...

[Jeremy Hylton]

On Thu, 2003-06-12 at 05:27, Chris Withers wrote:
> Hi,
> 
> I added a 'Recent Postings' box to the right of http://www.bay-c.co.uk.
> It's basically a ZCatalog search sorted on date of the contents of a Squishdot 
> Site done in a Python Script and presented through a ZPT.
> 
> However, I'm now starting to see these:
> 
> Error Value: ZODB.POSException.ReadConflictError on database read conflict error 
> (oid 000000000001dee1, class BTrees.IOBTree.IOBucket) in 
> "standard:'here/recent_helper'", at line 2, column 1

I don't know where this error message comes from, but I'll mention that
read conflicts are a bit different than write conflicts.  In particular,
if a transaction gets a read conflict before it modifies any objects,
then aborting the transaction and trying again won't help.

This is a bug, which is fixed in ZODB 3.2 / Zope 2.7.

The problem is that aborting a transaction only affects database
connections (_p_jars) that are registered with the transaction.  A
connection only registers when one of its objects is modified.

Jeremy