[ZODB-Dev] Re: Understanding conflicts

[Tres Seaver]

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Jim Carroll wrote:
> Hi,  I've got a problem with a website where occasionally we send multiple
> e-mail messages when really we only want to send one.
> 
> The last time it happened, I noticed that there was a Conflict Error at the same
> time as the e-mail send.
> 
> The code that's running essentially does:
> 
>    add message to Persistent list in object
>    get_transaction().commit()
>    send_email()
> 
> We are using Zodb 3.3a3, and ZEO 2.3a3.
> 
> I've read that when a transaction retries, it re-runs code on the server side. 
> How can I verify that that's what my setup would do? (my maillog on my server
> side doesn't show the duplicate e-mails, but I might not be looking far enough
> back in the logs.)

The "stock" MailHost does have this problem.  There are a couple of
alternatives which address it:

- - "zope.sendmail",
  http://svn.zope.org/zope.sendmail/trunk/README.txt?rev=72633&view=auto

- - "MaildropHost",
   http://www.dataflake.org/software/maildrophost


Tres.
- --
===================================================================
Tres Seaver          +1 540-429-0999          tseaver at palladion.com
Palladion Software   "Excellence by Design"    http://palladion.com
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