magento order id increment jumps - magento

Question

For some reason order ID's (increment_id on sales_flat_order table) are not incrementing subsequently on my Magento 1.6.1. This is how it looks after a number of live orders placed:
increment_id created_at updated_at
100000001 2011-12-14 12:35:24 2011-12-14 12:35:25
100000002 2011-12-14 13:02:39 2011-12-14 13:02:39
100000003 2011-12-14 13:04:18 2011-12-14 13:04:18
100000004 2012-02-01 16:54:58 2012-02-01 16:54:58
100000005 2012-03-14 12:22:35 2012-03-14 12:22:35
100000006 2012-03-20 13:10:48 2012-03-20 13:10:48
100000011 2012-03-29 20:58:48 2012-03-29 20:58:48
100000012 2012-03-29 21:06:43 2012-03-29 21:06:43
100000013 2012-03-30 10:48:20 2012-03-30 10:48:21
100000014 2012-03-30 13:05:40 2012-03-30 13:05:41
100000015 2012-04-03 15:51:01 2012-04-03 15:51:02
100000016 2012-04-19 15:00:49 2012-04-19 15:00:50
100000017 2012-05-09 12:09:21 2012-05-09 12:09:22
100000019 2012-05-24 05:35:35 2012-05-24 05:35:36
100000020 2012-05-24 05:41:11 2012-05-24 05:41:12
100000008 2012-05-24 05:48:52 2012-05-24 05:48:53
My question is why is Magento jumping increments sometimes? And worse yet, in my example order with increment 100000008 goes after 100000020. Does someone know why this is happening and if there's a way to fix it?

Answer 1

This is normal, albeit understandably disconcerting.
When Magento enters the checkout process it 'reserves' an increment_id and places it on the quote (cart) object. You can see the code that gets an increment id at:
Mage_Eav_Model_Entity_Type::fetchNewIncrementId()
The last used ID for each store is stored in eav_entity_store. If a customer abandons their cart (ie the quote object) before completing the checkout process, the reserved increment_id will never show up on an order. You can see this effect sometimes in the order numbers as they come in on a busy store - occassionally a really old order id comes through in the day's orders from a customer that is checking out an old cart.
This behaviour exists to allow Magento to send payment gateways the final order id (increment_id), before the order is completed allowing the gateway to associate the order id with the order. If the customer abandons the payment process in the gateway, the order id is dead (or more correctly still attached to the quote).
You can see this happening in the PayPal express module at:
Mage_Paypal_Model_Express_Checkout::start()
which calls
Mage_Sales_Model_Quote::reserveOrderId()
If you want to find your 'missing' increment_ids, take a look in sales_flat_quote under the field reserved_order_id. You should see them attached to unconverted quote objects (carts).
This behaviour can create issues with some payment gateways; Moneris comes to mind. When you send Moneris' hosted paypage the same order id twice, it chokes and creates a cryptic error state for the customer. This condition occurs when the customer visits the hosted pay page, backs out and re-visits the page. Hence in some cases, it is necessary to re-generate the order id associated with the quote object programmatically.

Answer 2

I was facing the same issue but it was only when the server was hit with a huge amount of load. This issue occurs because the db goes into the lock state while converting quote into order. On further inspection, I found out that the issue was that it tried to write into sales_flat_order_grid table within transaction right after insert into sales_flat_order table. With concurrent queries it caused locking collisions. The real solution is to move stuff of sales_flat_order_grid out of the transaction.
The link helped me understand the issue
The patch resolved the issue for me.
You have to remove function _afterSave from the Mage_Sales_Model_Abstract and add
public function afterCommitCallback(){
if (!$this->getForceUpdateGridRecords()) {
$this->_getResource()->updateGridRecords($this->getId());
}
parent::afterCommitCallback();
}
Let me know if it solves the problem for you.

Answer 3

We have had this same issue multiple times over the past couple of months. Upon checking our payment service provider transaction list we see 1000's of low value (micro) transactions being declined due to potential fraud issues. My opinion is that a fraudster is trying to use our checkout process to probe the list of cards they have to find out what cards are valid and what cards are dead. I have reported it to action fraud, our web host and our payment provider.
In summary, my advise would be for you to check your PSP list of transactions for the same time period.
Good luck with it,
Brisc.