Hello, first, let me give you an idea of the problem I'm facing. This is a company with a fruit packaging plant, they use several printers for the barcodes they attach in fruit boxes, clamshells and pallets. There is a Django table that keeps track of the current number for each one (caja, clamshell and pallet):
<https://lh3.googleusercontent.com/-dmAawvjfCg4/ViZuR_tPlvI/AAAAAAAAY08/zD0pPBWATeE/s1600/series.png> They don't want to be holes in the middle, if the current number for a box is *00071799* then there must be boxes from *00000001 *to *00071798*. These numbers are used as primary keys for the Caja, Clamshell and Pallet models. The printing process is using atomic transactions: @transaction.atomic def print_barcodes(request): tid = transaction.savepoint() # lot of code here if error: transaction.savepoint_rollback(tid) # ... return JsonResponse(response) We are getting a lot of these: _mysql_exceptions.IntegrityError: (1062, "Duplicate entry 'XXXXXXXXXX' for key 'PRIMARY'") Which means we have a fault in the process or maybe we are improperly using transactions. Help will be much appreciated regarding the problem and the following questions: 1. If we print 10 boxes from *00000001 *to *00000010* and say (exaggeratedly) each box takes 1 second to print. Then, another guy wants to print boxes while the first transaction is still active, will he get *00000011*? Considering that the numbers are updated during the transaction. 2. Do transactions stack and lock the tables? Thanks a lot -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscr...@googlegroups.com. To post to this group, send email to django-users@googlegroups.com. Visit this group at http://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/df8f520b-06ae-4627-88a5-1b51c607052b%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
