Try this https://github.com/RoaringBitmap/RoaringBitmap
-----邮件原件----- 发件人: Sergi Vladykin [mailto:[email protected]] 发送时间: 2017年1月21日 21:29 收件人: [email protected] 主题: Re: Optimize integer sets. I'd suggest to have a single abstract class `Partitions` with protected constructor and static factory method. This will allow to add different optimized for any particular case implementations transparently. Sergi 2017-01-21 15:26 GMT+03:00 Andrey Mashenkov <[email protected]>: > Hi Guys > > Alexei Scherbakov report a ticket few time ago [1]. The solution look > promissing. > > Alexei, you wrote that this can save some memory. More over replacing > linked Set structure to array based bit-set can give a speed-up due to > array based structures are cache friendly. > > But one thing is not clear for me how we will handle sparsed bit-sets? > For example, if we have 1024 partiotions (as it is by default) and > have much nodes, e.g. 512. In this case, bit-set will occupy 256 bytes > that seem to be more than Set<Integer>. > > What do you mean exactly to use bit-set as more compact structure then > Set<Integer> or bit-set with some additional compression? > > I would thought, we can use hash-set with open addressing in some > cases like that to get gain of array bases structures over linked > structures and save memory? > For example, we could use such hash-set for small data (64bytes as > cache line size) and use bit-sets for bigger data, if it's possible of course. > > > Thoughts? > > [1] https://issues.apache.org/jira/browse/IGNITE-4554 >
