2010/6/22 Maxim Kramarenko <maxi...@trackstudio.com>: > Hello! > > I use OrderPreservingPartitioner and assign tokens manually. > > Questions are: > > 1) Why range sorted in alphabetical order, not numeric order ? > It was ok with RandomPartitioner
With RandomPartitioner, tokens are md5 hashes, thus number and the comparison between two tokens is the numeric one. With OrdrerPreservingPartitioner, tokens are the keys themselves, that is to say Strings, and the comparison is (utf8) String comparison (hence the alphabetic sorting). Note that as such, when switching from RP to OPP, you most certainly don't want to keep the same tokens (as they represents very different things (md5 hahes vs string key)). > > Address Status Load Range Ring > > 84000000000000000000000000000000000000 > 172.19.0.35 Up 2.47 GB 0 |<--| > 172.19.0.31 Up 1.85 GB 112000000000000000000000000000000000000 > | ^ > 172.19.0.33 Up 1.46 GB 142000000000000000000000000000000000000 > v | > 172.19.0.30 Up 1.44 GB 28000000000000000000000000000000000000 > | ^ > 172.19.0.32 Up 2.63 GB 56000000000000000000000000000000000000 > v | > 172.19.0.34 Up 3.29 GB 84000000000000000000000000000000000000 > |-->| > > 2) what is the token range ? For example, all our keys starts with customer > number (a few digits), but number is only small part of ASCII table. > > What is the best way to assign tokens manually when using > OrderPreservingPartitioner ? The first thing is to find (estimate most probably) the domain and repartition of the key you will use (note that this is really the hard part as most of the time you can only guess what the repartition will be and most of the time you will be wrong anyway and get bad load balancing). But when you know that, you just assign as tokens the particular keys that split this repartition the more evenly possible (and split here is with respect to (utf8) string comparison). -- Sylvain > > -- > Best regards, > Maxim mailto:maxi...@trackstudio.com > > LinkedIn Profile: http://www.linkedin.com/in/maximkr > Google Talk/Jabber: maxi...@gmail.com > ICQ number: 307863079 > Skype Chat: maxim.kramarenko > Yahoo! Messenger: maxim_kramarenko >
