What do you mean by kill the region server? kill -9, unplug the power, cut the network?
When you flush commits, it means the data made it to the RS. Without WAL, it doesn't mean it made it to HDFS. It can be only in memory (memstore). When you kill the process abruptly then, it will lose the data.
A normal shutdown flushes the memstore to HDFS, I think.
Van: Qing Yan [[email protected]
Verzonden: vrijdag 27 mei 2011 4:43
Aan: [email protected]
Onderwerp: data loss after killing RS
I found something strange, here is the test case:
1) Process A insert data into a particular hbase region, WAL off, AutoFlush
2) Process A issues htable.flushCommits(), no exception thrown, write down
the row key.
4) Kill the region server manually
5) Process B query the row key, but can't find it no matter how many times
it retries. (In the meantime via
hbase UI, the region get reassigned)
Is this expected? I am using the lastest Cloudera build.