用一个TreeMap来作为环,key为虚拟节点下标,value为真实节点的hash。个人感觉可以加一个Map<T, Set>来维护真实节点-虚拟节点的关系。 /*** 一致性Hash算法* 算法详解:http://blog.csdn.net/sparkliang/article/details/5279393* 算法实现:https://weblogs.java.net/blog/2007/11/27/consistent-hashing* @author...
unless Key happens to have some undesirable properties. In this case, the choice of hash function needs to be carefully considered. For instance, if the table size the is 10 and the keys all end in zero, then the standard hash function is a bad choice. For reasons ...
The process of calculating element’s unique address is called hashing and the algorithm how it is done is called a hash function. Hash table illustration Now you probably already see a problem. How does hash function manages to give unique address to every element? Well it doesn’t. It ...
–Use hash function h(K) = K%M, where M = N/L = 100 is the number of buckets: 0 ≤ h(K) < M. –So 100232, 433, and 10002332482 go into different buckets, but 10, 400210, and 210 all go into the same bucket. 为了达到这一目的,必须有一种方法将元素转为桶的编号:一个哈希函数。
In general, must re-hash all table items. Still, this operation constant time per item, So by doubling table size each time, get constant amortized time for insertion and lookup (Assuming, that is, that our hash function is good).
最近在思考一个问题,如果一个存储引擎不需要支持范围查询,那么使用hashtable这样的数据结构是否更合适?恰好看到了lotusdb中使用了一个diskhash的库,从源码看是使用了一种Linear Hashing的哈希表数据结构,由于磁盘与内存的特性不同,因此磁盘哈希结构与常见的内存hashtable不太一样,特意研究了下。
目录 一、一致性Hash(Consistent Hashing)原理剖析 二、一致性hash算法的Java实现 一、一致性Hash(Consistent Hashing)原理剖析 引入 一致性哈希算法是分布式系统中常用的算法。一致性哈希算法解决了普通余数Hash算法伸缩性差的问题,可以保证在上线、下线服务器的情况下尽量有多的请求命中原来路由到的服务器。 在业务开发...
Add additional bits to the hash value. Re-compute the hash function. Else Add data to the bucket, If all the buckets are full, perform the remedies of static hashing.Hashing is not favorable when the data is organized in some ordering and the queries require a range of data. When data...
Jump Consistent Hashing 算法和一致性hash算法的优劣 Jump Consistent Hashing 和 一致性哈希(Consistent Hashing)是两种常见的分布式哈希算法,它们都用于解决数据分片和负载均衡的问题。然而,这两种算法在设计目标、性能特点和适用场景上存在显著差异。以下是它们的优劣对比,以及为什么可能选择 Jump Consistent Hashing 而不...
The specific hash function always produces fixed-size output. It should be complex enough to minimize the risk of collision. As an example, let’s analyze a hash function used in Java’sStringclass: public int hashCode() { int h = hash; if (h == 0 && value.length > 0) { char val...