Client RegionServer RegionServer RegionServer Handler-1 Handler-2 Handler-3 Services RegionServer RegionServer RegionServer Handler-1 Handler-1 Handler-1 Services Get Stuck Get Stuck Get Stuck All

By default, we will pre-allocate 2MB *2 for each RPC handler ( The handler count is determined by the config: hbase.regionserver.handler.count, it has the default value 30) . That’s to say, if

BucketCache(offheap) to onheap. Rpc Handler offheap onheap BucketCache StoreFileScanner Return a DirectByteBuffer(off, len) which reference to the offheap block. Rpc Handler offheap onheap Use the DirectByteBuffer

的读性能 Postgres Conference China 2016 中国用户大会 写性能 • HBase理论平均写延时<10ms，时间复杂度O(1) • 没有可用的handler响应 – 考虑增加handler数目或硬件资源 • 更常见的情况是95%－99%的写入都很快，但有些 写入非常慢，甚至慢上万倍，一般问题在服务器端： – 写入Memstore慢 • HLog写入超时——考虑HDFS及硬盘异常