bq. if I batch the deletes into one big one at the end (rather than while I'm scanning) That's what you should do.
See also HBASE-6284 where an optimization, HRegion#doMiniBatchDelete(), is under development. On Wed, Jun 27, 2012 at 2:03 PM, Jeff Whiting <[email protected]> wrote: > I'm struggling to understand why my deletes are taking longer than my > inserts. My understanding is that a delete is just an insertion of a > tombstone. And I'm deleting the entire row. > > I do a simple loop (pseudo code) and insert the 100 byte rows: > > for (int i=0; i < 50000; i++) > { > puts.append(new Put(rowkey[i], oneHundredBytes[i])); > > if (puts.size() % 1000 == 0) > { > Benchmark.start(); > table.batch(puts); > Benchmark.stop(); > } > } > > > The above takes about 8282ms total. > > However the delete takes more than twice as long: > > Iterator it = table.getScannerScan(rowkey[0]**, > rowkey[50000-1]).iterator(); > while(it.hasNext()) > { > r = it.next(); > deletes.append(new Delete(r.getRow())); > if (deletes.size() % 1000 == 0) > { > Benchmark.start(); > table.batch(deletes); > Benchmark.stop(); > } > } > > The above takes 17369ms total. > > I'm only benchmarking the deletion time and not the scan time. > Additionally if I batch the deletes into one big one at the end (rather > than while I'm scanning) it takes about the same amount of time. I am > deleting the entire row so I wouldn't think it would be doing a read before > the delete (http://mail-archives.apache.**org/mod_mbox/hbase-user/** > 201206.mbox/%**3CE83D30E8F408F94A96F992785FC2**9D82063395D6@s2k3mntaexc1.* > *mentacapital.local%3E<http://mail-archives.apache.org/mod_mbox/hbase-user/201206.mbox/%3CE83D30E8F408F94A96F992785FC29D82063395D6@s2k3mntaexc1.mentacapital.local%3E> > ). > > Any thoughts on why it is slower and how I can speed it up? > > Thanks, > ~Jeff > > -- > Jeff Whiting > Qualtrics Senior Software Engineer > [email protected] > >
