On 10/25/2012 07:44 AM, Anoop Sam John wrote: > Hi > Can you tell more details? How much data your scan is going to retrieve? it's a full scan of 1.7TB of data on 62 regionserver+master and ZK quorum machines. I hoped that in some way block caching may slightly improve the read perfomances. hbase version 0.92.1. scan with hadoop 1.0.3 throught tableinputformat.
> What is the time taken in each attempt ? about 1h20' > Can you observe the cache hit ratio? 0% while the blockCacheSizeMB=1649.8 > What is the memory avail in RS? maxHeapMB=8179 ( in hbase-env.sh: export HBASE_REGIONSERVER_OPTS="-Xmx8g -Xms8g -Xmn128m -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=70" ) > .....Also the cluster details and regions > > 1525 regions regions too big? I created a pre-splitted table before bulk importing. I don't understand why the regions didn't increase afterwards. hbase.hregion.max.filesize is the default 256MB and the regions are roughly 1GB. How come hbase have not split'em ? but that's another question....
