Double hashing is a find thing. To actually answer the question, though, I would recommend Murmurhash or JOAAT ( http://en.wikipedia.org/wiki/Jenkins_hash_function)
On Wed, Mar 16, 2011 at 3:48 PM, Andrey Stepachev <oct...@gmail.com> wrote: > Try hash table with double hashing. > Something like this > > http://www.java2s.com/Code/Java/Collections-Data-Structure/Hashtablewithdoublehashing.htm > > 2011/3/17 Peter Haidinyak <phaidin...@local.com> > > > Hi, > > This is a little off topic but this group seems pretty swift so I > > thought I would ask. I am aggregating a day's worth of log data which > means > > I have a Map of over 24 million elements. What would be a good algorithm > to > > use for generating Hash Codes for these elements that cut down on > > collisions? I application starts out reading in a log (144 logs in all) > in > > about 20 seconds and by the time I reach the last log it is taking around > > 120 seconds. The extra 100 seconds have to do with Hash Table Collisions. > > I've played around with different Hashing algorithms and cut the original > > time from over 300 seconds to 120 but I know I can do better. > > The key I am using for the Map is an alpha-numeric string that is > > approximately 16 character long with the last 4 or 5 character being the > > most unique. > > > > Any ideas? > > > > Thanks > > > > -Pete > > >
