Hi, I use reversed hex for auto-incremented ids. For example: id=123456, row key=042E1 id=123457, row key=142E1 I've started use this approach recently, but it seems it works pretty well. All regions are distributed uniformly, with no hot-spotting
2012/7/20 Jonathan Bishop <[email protected]> > Hi, > > I know it is a commonly suggested to use an MD5 checksum to create a row > key from some other identifier, such as a string or long. This is usually > done to guard against hot-spotting and seems to work well. > > My concern is that there no guard against collision when this is done - two > different strings or longs could produce the same row-key. Although this is > very unlikely, it is bothersome to consider this possibility for large > systems. > > So what I usually do is concatenate the MD5 with the original identifier... > > MD5(id) + id > > which assures that the rowkey is both randomly distributed and unique. > > Is this necessary, or is it the common practice to just use the MD5 > checksum itself? > > Thanks, > > Jon >
