I created HBASE-6287 <https://issues.apache.org/jira/browse/HBASE-6287> for porting HBASE-5941 to trunk.
Jeff: What version of HBase are you using ? Since HBASE-5941 is an improvement, a vote may be raised for porting it to other branches. On Wed, Jun 27, 2012 at 4:15 PM, Jeff Whiting <[email protected]> wrote: > Looking at HBASE-6284 it seems that deletes are not batched at the > regionserver level so that is the reason for the performance degradation. > Additionally HBASE-5941 with the locks is also contributing to the > performance degradation. > > So until those changes get into an hbase release I just have to live with > the slower performance. Is there anything I need to do on my end? > > Just as a sanity check, I tried setting a timestamp in the delete object > but it made no difference. I'll batch my deletes at end as you suggested > (as memory allows). > > Thanks, > ~Jeff > > On 6/27/2012 4:11 PM, Ted Yu wrote: > >> Amit: >> Can you point us to the JIRA or changelist in 0.89-fb ? >> >> Thanks >> >> >> On Wed, Jun 27, 2012 at 3:05 PM, Amitanand Aiyer <[email protected]> >> wrote: >> >> There was some difference in the way locks are taken for batched deletes >>> and puts. This was fixed for 89. >>> >>> I wonder if the same could be the issue here. >>> >>> Sent from my iPhone >>> >>> On Jun 27, 2012, at 2:04 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] >>>> >>>> > -- > Jeff Whiting > Qualtrics Senior Software Engineer > [email protected] > > > >
