Sorry if this double posts... may have used the wrong email first. On Oct 21, 2013, at 6:36 AM, Michael Segel <[email protected]> wrote:
> > Lets look at what you are trying to do... > > You want to take data where the key is a timestamp (long datatype) > You append it to a salt value 1=10 or 0-9 your example doesn't say... > > You have a couple of problems with your choice of a key... > > First after your initial 10 splits, you will still end up with writing > everything to the left side of the region. > This means that when the region splits... all writes will still be to the > left leaving your regions still 1/2 the size that they could be with the with > the exception of your last set of salted regions. In this case 10 which will > grow and then split. > > Is this a bad thing? Maybe yes, maybe no. > > The issue is that you will then have to write 10 queries with a start key and > a stop key to get the range of your timestamp. > > > That would work, however... > > 1) Justify why you want/need to use a timestamp as a key for the row. > > I'd say tell us more about the use case and why the access pattern. > > Salting is bad in that the salt is disassociated to the underlying key. > Taking the key's hash, truncating it and preprending (if this is an actual > word) to the key gives you a random key where if you know the rowkey, you can > hash it. > > My suggestion is that you rethink your key... > > > > On Oct 20, 2013, at 11:31 PM, Tony Duan <[email protected]> wrote: > >> Alex Vasilenko <aa.vasilenko@...> writes: >> >>> >>> Lars, >>> >>> But how it will behave, when I have salt at the beginning of the key to >>> properly shard table across regions? Imagine row key of format >>> salt:timestamp and rows goes like this: >>> ... >>> 1:15 >>> 1:16 >>> 1:17 >>> 1:23 >>> 2:3 >>> 2:5 >>> 2:12 >>> 2:15 >>> 2:19 >>> 2:25 >>> ... >>> >>> And I want to find all rows, that has second part (timestamp) in range >>> 15-25. What startKey and endKey should be used? >>> >>> Alexandr Vasilenko >>> Web Developer >>> Skype:menterr >>> mob: +38097-611-45-99 >>> >>> 2012/2/9 lars hofhansl <lhofhansl@...> >> Hi, >> Alexandr Vasilenko >> Have you ever resolved this issue?i am also facing this iusse. >> i also want implement this functionality. >> Imagine row key of format >> salt:timestamp and rows goes like this: >> ... >> 1:15 >> 1:16 >> 1:17 >> 1:23 >> 2:3 >> 2:5 >> 2:12 >> 2:15 >> 2:19 >> 2:25 >> ... >> >> And I want to find all rows, that has second part (timestamp) in range >> 15-25. >> >> Could you please tell me how you resolve this ? >> thanks in advance. >> >> >> Tony duan >> >> > > The opinions expressed here are mine, while they may reflect a cognitive > thought, that is purely accidental. > Use at your own risk. > Michael Segel > michael_segel (AT) hotmail.com > > > > > >
