If you're using USPS Real Time Shipping API to obtain the shipping rates when customers enter the cart or checkout portion of your shopping cart then you've probably noticed that the page goes to either a slow crawl or it produces SQL Errors.
The issue is not on our server, the issue is with USPS. We were first made aware of this issue yesterday about 3pm CDT when a number of our X-Cart users started opening tickets regarding their checkout not working, or pages running slow. Since then we've received complaints from a number of different shopping carts (X-Cart, Magento, osCommerce) all stating the same issue.
We posted a thread on the X-Cart Forums at http://forum.x-cart.com/showthread.php?t=51886 to document the issue, and since then, more than 40 additional posts have been added to the thread confirming the event. osCommerce also has a thread documenting the issue.
Until a few hours ago, USPS claimed that there was no issue, however now when you call them they have an automated message to say that they are aware of the event (20 hours later).
If you're experiencing checkout issues and pages running slow when entering the cart, turn off the Real Time Shipping calculations for USPS until USPS fixes their problem. This will at least allow your visitors to checkout using an alternate shipping method.
We will be updating this thread as we get more information, and also on our blog at http://blog.handsonwebhosting.com
