Paypal IPN Issuing Duplicate Orders

I use Paypal IPN as one of my payment methods.

I had the settings tweaked 2 months ago when I was getting duplicate orders with one payment transaction (I dont recall the tweak) , everything was fine after that.

However suddenly since the last 2 days we are getting duplicate orders again , the transactions id's are the same and the order numbers are consecutive .

What can I do to solve this problem , this has happened about 5 times in 2 days

Log a ticket with PayPal https://www.paypal.com/mts

Meanwhile, turn on debug logging and check the 2nd line of the logs for the originating address, and see if you're getting duplicates because of duplicate transmissions from PayPal: http://www.zen-cart.com/forum/showthread.php?p=598477#post598477

Thanks for the reply.

I have opened a ticket and will let you know about the log report.

I've got more info on this and some thoughts on fixing it (there's a discussion here - http://www.zen-cart.com/forum/showthread.php?p=598553#post598553 about this problem). I've looked at my log files and reviewed the PayPal module code to figure out what's happening.

We're getting multiple IPN responses from PayPal. This seems to have started recently (in the last few days from looking at some other forums as well). The responses are so close together (I have one case of four in the same minute), that when the presence of the TXN_ID is checked for in the paypal table, the TXN_ID is not there yet so each process adds it's own order to the order table and it's own entry in the paypal table.

It seems to be clearly a PayPal problem, and the timing of the multiple responses makes it difficult to solve. A perfect solution involves making the test for the TXN_ID and the insertion of the record an atomic operation.

I'd be happy to collaborate on a fix with someone who has more knowledge of the PayPal module design.

david

It was a PayPal system bug. They fixed it at 4:50AM today:

http://www.pdncommunity.com/pdn/blog/article?message.uid=92385