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From Peter Schuller <peter.schul...@infidyne.com>
Subject Re: error using get_range_slice with random partitioner
Date Sat, 07 Aug 2010 09:35:33 GMT
>> 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

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