I would convert each id to long and then use Bytes.toBytes to convert this long to a byte array. If it is an int then even better. Now, write all 3 longs one after another to one array which will be your rowkey. This gives you: * fixed size * small row key - 3*8 bytes if you use long and 3*4 for int.
Why do you need to use prefix split policy? On Monday, March 4, 2013, Lukáš Drbal wrote: > Hi, > > i have one question about rowkey design and presplit table. > > My usecase: > I need store a lot of comments where each comment are for one article and > this article has one category. > > What i need: > 1) read one comment by id (where i know commentId, articleId and > categoryId) > 2) read all coments for article (i know categoryId and articleId) > 3) read all comments for category (i know categoryId) > > From this read pattern i see one good rowkey: > <categoryId>_<articleId>_<commentId> > > But here i don't have fixed size of rowkey, so i don't know how to define > split pattern. How can be this solved? > This id's come from external system and grow very fast, so add some like > "padding" for each part are hard. > > Maybe i can use hash function for each part > md5(<categoryId>_md5(<articleId>)_md5(<commentId>), but this rowkey is very > long (3*32+2 bytes), i don't have experience with this long rowkeys. > > Can someone give me a suggestions please? > > Regards > > Lukas Drbal >
