Inline. J-D
On Thu, May 26, 2011 at 5:12 AM, elton sky <[email protected]> wrote: > I am new to hbase and I got a few questions: > 1. tables are divided into regions and allocated to region servers. what is > the allocation policy? Ted Yu recently wrote up a blog post about balancing in HBase: http://zhihongyu.blogspot.com/2011/04/load-balancer-in-hbase-090.html > 2. From my understanding, if a region server get requests for data on the > same host, for data locality, all requests will be served by the local host, > right? HBase doesn't decide anything, it's a HDFS responsability: http://hadoop.apache.org/common/docs/r0.20.2/hdfs_design.html#Replica+Selection > Unless the max connection for the data node is reached. If this is > the case, for random read request, can requests access the data > simultaneously? I'm not sure I understand this question, could you please clarify? > 3. When doing a update, e.g. add a new version to a column, how the system > lock the record? With a row lock. Regarding HBase's ACID guarantees in general, please see http://hbase.apache.org/acid-semantics.html J-D
