I did the same when our mysql queries were taking around 30 seconds each (iirc the db had about 20 million rows, but I didn't have anything to do with it). The

I did the same when our mysql queries were taking around 30 seconds each (iirc the db had about 20 million rows, but I didn't have anything to do with it). The replacement I wrote ran each query in about 100ms. The hard part was in getting my data structures good enough that the whole dataset could fit in 3GB (that's how much memory was in the server I was using).