[ZODB-Dev] Wrong blob file being returned (similar to https://mail.zope.org/pipermail/zodb-dev/2011-February/014067.html )

[William Heymann]

On Tuesday 12 July 2011, steve wrote:
> Hi,
> 
> I have a setup where 4 ZEO clients running on separate machines connect to
> a single DB server which runs on a different system by itself. The ZEO
> clients and the DB server all are at version ZODB3-3.10.2. Now, since the
> last few weeks some of our users have been reporting that they
> occasionally see incorrect images being returned.

One thing you may want to look at is the load balancer. Apache has a bug that 
keeps being opened and closed again for swapping data between requests under 
load. Because it happens at the apache level and not the zope level you will 
never see this problem in any of the zope logs.

Just make sure you don't have a similar situation or you could end up 
debugging the wrong thing to a huge waste of time. In my case I spent a lot of 
time debugging zope and when I finally discovered it was apache that was 
screwing up I ended up just dumping apache for nginx.