Only 4% in the 12 node cluster case? I'd guess you're using not more cores then before (i.e. the parallelizing on the client is bad), or you're IO bound (which is unlikely). Are all your regionserver busy in terms of CPU?
-- Lars ----- Original Message ----- From: Gurjeet Singh <[email protected]> To: [email protected] Cc: Sent: Monday, August 13, 2012 3:12 PM Subject: Re: Slow full-table scans Okay, I just ran this experiment. It did speed things up, but only by 4%. This all still seems awfully slow to me - does someone have another suggestion ? Thanks in advance! Gurjeet On Mon, Aug 13, 2012 at 12:51 AM, Gurjeet Singh <[email protected]> wrote: > Thanks a lot! > > On Mon, Aug 13, 2012 at 12:27 AM, Stack <[email protected]> wrote: >> On Mon, Aug 13, 2012 at 6:10 AM, Gurjeet Singh <[email protected]> wrote: >>> Thanks Lars! >>> >>> One final question : is it advisable to issue multiple threads >>> against a single HTable instance, like so: >>> >>> HTable table = ... >>> for (i = 0; i < 10; i++) { >>> new ScanThread(table, startRow, endRow, rowProcessor).start(); >>> } >>> >> >> Make an HTable per thread. See the class comment: >> http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html >> >> St.Ack
