I've observed a strange behavior whereby a customer managed to place three orders in quick succession which had the same order numbers.

Each order was based on the same quote_id which in turn represents the correct reserve_order_id value. The orders were placed at these times:

  • 2014-12-15 16:41:11
  • 2014-12-15 16:43:10
  • 2014-12-15 16:46:39

The first order had the order confirmation email sent to the customer, but the second and third orders did not.

How did each order have the same order number even though the sales_flat_quote table seemingly correctly set the value for reserve_order_id?

P.S. I've noticed this same issue pop up about 2 - 3 times a month, so very rarely (upwards of 800 orders are placed monthly).

Edit 1: As soon as a customer clicks the Place Order button during checkout on our website, the button vanishes & the following loading symbol is displayed:

enter image description here

As such this cannot be as a result of the customer repeatedly hitting the Submit Order button.

  • 1
    You're assuming no Javascript issues and that the script that hides your Submit Order button works on every platform. I had to setup event tracking on the checkout page to rule out stealthy issues like this before. You can use Google Analytics or create your own form of analytics but I like to know how long my users spend on the site, how many times they clicked certain buttons, if they ever saw the success page, etc. Sometimes advanced logging is the only way to track down UX issues like this. Try this: trackjs.com
    – sparecycle
    Commented Dec 22, 2014 at 19:23

2 Answers 2


I've seen something like this before where a shop was a bit slow on redirecting the customer from the checkout to the Payment portal.

The user clicked the submit button multiple times which caused several orders to be created. So there isn't really a technical issue here, more an user UI issue.

I would advice to first of all call the customer and ask him what happened and maybe display a clear loader or even hide the submit button after the user has clicked it in the checkout

  • Thanks a lot for the input, really appreciate it. I also had a sneaking suspicion that this may be the case, but we actually do get rid of the Submit Order button the moment it is clicked. We also do not redirect to a payment portal. This one really has me stomped.
    – Moose
    Commented Dec 17, 2014 at 12:40

Use Kirchbergerknorr_DuplicateOrders module to change status of duplicated orders.

Use this SQL to check how many duplications you have:

increment_id, state, email_sent, grand_total, created_at, quote_id as q, 
(select count(x.quote_id) 
from sales_flat_order as x 
where x.quote_id = q 
group by x.quote_id) as count 
from sales_flat_order having count > 1 order by quote_id desc, created_at desc;

As you see that problem is that some emails wasn't sent.

Possible reasons can be:

  • overloaded sendmail
  • blocked sendmail
  • closed ports

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