eelixduppy - 1:16 pm on Jul 19, 2012 (gmt 0)
There probably isn't going to be a "best" solution for something like this. If what you have works than why second-guess it? Is it producing undesirable performance?
If I were to write something like this, I would chose something other than PHP (probably Java) and make it parse the data concurrently to maximize my performance. For 20k update records, any solution should work because its such a small amount of data. If you were going to do a full update of all the data, this may take a very long time if you are single threaded.