https://forum.productcart.com/ Copyright (c) 2006-2013 Web Wiz Forums - All Rights Reserved. Wed, 08 Apr 2026 23:16:25 +0000 Wed, 02 Jun 2010 03:33:28 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.04 360 https://forum.productcart.com/RSS_post_feed.asp?TID=3748 https://forum.productcart.com/forum_images/pc_logo_50.png https://forum.productcart.com/ https://forum.productcart.com/inventory-management-in-v4_topic3748_post14601.html#14601 Author: rotokirby
Subject: 3748
Posted: 02-June-2010 at 3:33am

I'll give Express Checkout a closer look....I just don't like the whole back and forth required with Express Checkout and the fact that the user experience changes so much. But if we could still do a last minute inventory check (I guess when the shipping is chosen) then we could at least cut down on the chance of overselling.

I've considered just disabling Paypal when we're anticipating a heavy selling item, but we don't always know, and I don't want to annoy my customers who prefer Paypal.

It's a real head scratcher for sure.


]]> Wed, 02 Jun 2010 03:33:28 +0000 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14601.html#14601 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14600.html#14600 Author: ProductCart
Subject: 3748
Posted: 02-June-2010 at 3:17am

That's because the customer completely leaves the storefront and could take a while to log into her PayPal account to complete the purchase.

Have you tried disabling WPS and using Express Checkout instead? With EC the customer leaves the storefront, then comes back to ProductCart to perform some of the checkout steps there (e.g. picking the shipping option), and then goes back to PayPal to finalize the order.

The time "away" from ProductCart might be shorter with EC, so the issue might disappear.
]]> Wed, 02 Jun 2010 03:17:49 +0000 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14600.html#14600 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14599.html#14599 Author: rotokirby
Subject: 3748
Posted: 02-June-2010 at 3:11am

earlyimp wrote: Which PayPal payment option are you using?

We're using "Paypal Website Payments Standard."


]]> Wed, 02 Jun 2010 03:11:52 +0000 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14599.html#14599 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14598.html#14598 Author: ProductCart
Subject: 3748
Posted: 02-June-2010 at 3:07am

Which PayPal payment option are you using? 

Edited by earlyimp - 02-June-2010 at 3:07am]]> Wed, 02 Jun 2010 03:07:02 +0000 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14598.html#14598 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14597.html#14597 Author: rotokirby
Subject: 3748
Posted: 02-June-2010 at 2:56am

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.
]]> Wed, 02 Jun 2010 02:56:03 +0000 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14597.html#14597 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14596.html#14596 Author: ProductCart
Subject: 3748
Posted: 02-June-2010 at 2:28am

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).


Edited by earlyimp - 02-June-2010 at 2:29am]]> Wed, 02 Jun 2010 02:28:29 +0000 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14596.html#14596 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14594.html#14594 Author: rotokirby
Subject: 3748
Posted: 01-June-2010 at 10:31pm

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. ;)

]]> Tue, 01 Jun 2010 22:31:41 +0000 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14594.html#14594 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14559.html#14559 Author: Dayv3
Subject: 3748
Posted: 30-May-2010 at 4:31am


A good idea might be to debit the inventory when it is placed in the cart or upon payment submittal but also start a clock that after XX minutes it is returned to inventory if there is not a response from Paypal or the credit card processor.

I also guess the inventory could be checked in a few strategic places along the way.
]]> Sun, 30 May 2010 04:31:12 +0000 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14559.html#14559 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14556.html#14556 Author: rotokirby
Subject: 3748
Posted: 29-May-2010 at 8:37pm

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]]> Sat, 29 May 2010 20:37:22 +0000 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14556.html#14556 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14555.html#14555 Author: ProductCart
Subject: 3748
Posted: 29-May-2010 at 5:27pm

Good news! v4.1 (scheduled for release in about a month) will check the shopping cart array more frequently for products that are no longer in stock. Here is an excerpt from our internal development project:

• Invoke the routine:
  • When adding any products to the cart
  • When updating shopping cart content
  • When checking out
  • When loading the payment panel on OPC
  • When loading the payment page (if any)
    
    
• Message:
  • The message will be shown at the top of viewCart.asp
  • The message indicates:
  • "One or more products are no longer available. Another customer placed an order before you were able to do so, and reduced the inventory levels below the number of units that you are purchasing. Please reduce the amount of the products affected by this inventory problem, or remove them from the shopping cart. We sincerely apologize for the inconvenience.
  • The products affected are:
  • - PRODUCT_NAME
  • - PRODUCT_NAME

Keep in mind that technically 2 customers could check out at exactly the same time and neither would receive the message... however it should prevent most cases where 2 or more customers can checkout with the same item (assuming one of their orders will deplete the stock, and the store is using inventory management).



Edited by earlyimp - 29-May-2010 at 5:28pm]]> Sat, 29 May 2010 17:27:18 +0000 https://forum.productcart.com/inventory-management-in-v4_topic3748_post14555.html#14555