Inventory Management in v4?

Hi folks...can anyone running v4 please give me your experiences with inventory management?

We're currently on v3.5.1 and even though we've spent some extra money on coding to improve inventory controls, we still have issues with overselling items.

Here's a post about it on our website if you want a little more background:

A Quick Note About Overselling

Basically, I'm trying to determine if I should bother with going to v4 (we are planning to transition to v4, but probably not until early next year) or if I should be looking for a different solution, either via a Productcart developer or switching software entirely.

Thanks in advance.

That's good news, thanks.

Will the checks be against what is in active carts, or just against the total in the inventory? Or some combination of the two?

Unfortunately, debiting what is active in someone's cart can cause other problems. Prior to switching to PC we used Miva for a few years. The inventory controls in Miva debit the inventory count when an item is added to a user's basket, or at least they used to.

The problem then becomes one of never knowing just how many items are in carts vs. actually sold. Or you have users trying to "save" inventory for a friend by adding it to their cart, holding it there, then "releasing" it so their friend can buy it.

My fear is that no matter how it's managed, and no matter how often you check inventory, there's not an effective way to prevent overselling when you've got 5 items and 15 or more people trying to buy them at once. If 2, or 10, people hit the last checkpoint within a certain time frame (say you check inventory after the payment submit button is checked and then debit it once the payment is approved, which is how our store is modified to operate I believe) there is always going to be a window where inventory is no longer accurate, if even for a few seconds while waiting for a response from the payment processor.

Maybe the solution is to debit the inventory immediately upon payment submittal, but not wait for the response from Paypal or the credit card processor. Sure, you'll potentially end up debiting inventory unnecessarily if a payment is declined, but that's better than selling stuff we don't have to sell anymore.



Edited by rotokirby - 29-May-2010 at 8:38pm

I believe you run into other issues if you try to keep inventory numbers based on when it is added to the cart versus when you receive a completed order. Mainly that the number of calls to the database are increased and there is potentially a lot more strain on the site/server. That sure seemed to be the case with Miva back when we used it (and we still oversold stuff then too).

Don't get me wrong, I'm happy to have the problem of high demand, LOL, but it is frustrating to have to refund orders and annoy customers who may not try us again in the future. Most people don't understand how a "computer" can make the mistake of selling more than we tell it to. ;)

earlyimp wrote: We only update inventory when an order has been placed. What's different in v4.1 is that we added more checks on the inventory levels during the checkout process. This is to check whether the inventory levels have changed while the customer was going through checkout. For example, we do a last check on the payment step. So if there are 3 units left, customer A and customer B are both checking out at the same time, customer A submits an order for 2 units while customer B wishes to purchase 3 units, customer B would be "stopped" (e.g. on the payment step) as the inventory levels have changed while he/she was checking out (because customer A already completed the order).

Thanks for the explanation. Unfortunately, I don't think that'll fix our problem since the issue is happening primarily due to the time needed to verify a payment via Paypal. So as long as people get to the final step of the checkout and attempt a payment, if the item was in inventory at that moment, the order goes through. Since Paypal can take minutes to confirm a payment (resulting in the inventory being reduced), then we can still oversell.

Let me be clear for a moment here, I'm not criticizing EI. We've got some pretty unique demands that not very many other merchants/industries need met. I think the new checks sound like a reasonable way to handle inventory for most types of stores being served by EI.

earlyimp wrote: Which PayPal payment option are you using?

We're using "Paypal Website Payments Standard."