>> Another way to do it is to filter results to exclude columns received >> twice due to being on iteration end points. > > Well, depends on the size of your rows, keeping lists of 1mil+ column > names will eventually become reeeeally slow (at least in ruby).
You only have to keep track of a single column since you're iterating in order. > You only ever need to decrement/increment by one and that should be > pretty simple in almost all cases. Granted it was a little tricky for > TimeUUID, but we are talking bytes here, so there really is only 0-255 > +/- 1. If you are talking ASCII just trim that range down a little. It's not about incrementing/decrementing a single byte value, it's about decrementing the value of a byte string. Say you limit yourself to ascii a-z, but are still not finite in size. What's the entry lexicographically previous to b? Is it aaaaaaa? Is it aaaaaaaaaaaaaaaaaaaaaaaaaa? Whatever you pick there will always be a column with one additional a. In a less general case where you impose a length limit on the column name, you're fine. But not in the general case. -- / Peter Schuller
