On Fri, Feb 17, 2012 at 2:38 PM, Jeff Whiting <je...@qualtrics.com> wrote: > Is there way to profile a specific get request to see where the time is > spent (e.g. checking memstore, reading from hdfs, etc)? >
In 0.92, there is a slow query facility that dumps out context when queries are > some configured time. I presume you are on 0.90.x > We are running into a problem where a get after a delete goes really slow. > We have a row that has between 100 to 256 MB of data in it across a couple > hundred columns. After putting the data we can get the data out quickly (< > 100ms). So a get on "info:name" will take ~0.05110 seconds according the > hbase shell. We then delete the entire row (e.g. htable.delete(new > Delete(rowkey)). Most of the time after deleting the row trying the exact > same get on "info:name" becomes significantly slower (1.9400 to 3.1840 > seconds). Putting data back into "info:name" still results in the same slow > performance. I was hoping to profile the get to see where the time is going > and seeing what we can do to tune how we are using hbase. > If you flush the region -- you can do this from the shell -- is it still slow? If so, it means slowness is from accessing hfiles. Try copying the region content out and rig up a little harness to bring the region in a context free from the running cluser. See TestHRegion for sample code on how to stand up a HRegion instance. St.Ack
