For PageFilter : * Implementation of Filter interface that limits results to a specific page
* size. It terminates scanning once the number of filter-passed rows is > * the given page size. In your case, what should be the page size - 0 ? Cheers On Tue, May 19, 2015 at 8:30 PM, Jean-Marc Spaggiari < jean-m...@spaggiari.org> wrote: > Oh, I see! So basically we do a full table scan because it never returns a > 2nd row, so we never reach that break and we exit only when we reach the > end of the table. Therefore the same performances without the limit > parameter... > > Should we then try to add a filter like PageFilter to the scan if we have a > LIMIT? At least that might avoid a full scan? > > 2015-05-19 23:14 GMT-04:00 Matteo Bertozzi <theo.berto...@gmail.com>: > > > Take a look at table.rb _scan_internal() > > LIMIT is not passed to the server, so you fetch more rows > > > > > https://github.com/apache/hbase/blob/master/hbase-shell/src/main/ruby/hbase/table.rb#L495 > > > > Matteo > > > > > > On Tue, May 19, 2015 at 8:11 PM, Jean-Marc Spaggiari < > > jean-m...@spaggiari.org> wrote: > > > > > I tried to run scan/get/scan/get many times, and always the same > pattern. > > > You can remove the "LIMIT => 1" parameter and you will get the same > > > performances. > > > > > > Scan and get without the QC returns in very similar time. 191ms for > one, > > > 194ms for the other one. > > > > > > 2015-05-19 23:02 GMT-04:00 Ted Yu <yuzhih...@gmail.com>: > > > > > > > J-M: > > > > How many times did you try the pair of queries ? > > > > > > > > Since scan was run first, this would give the get query some > advantage, > > > > right ? > > > > > > > > Cheers > > > > > > > > On Tue, May 19, 2015 at 7:34 PM, Jean-Marc Spaggiari < > > > > jean-m...@spaggiari.org> wrote: > > > > > > > > > Are not Scan and Gets supposed to be almost as fast? > > > > > > > > > > I have a pretty small table with 65K lines, few columns (hundred?) > > > trying > > > > > to go a get and a scan. > > > > > > > > > > hbase(main):009:0> scan 'sensors', { COLUMNS => > > > > > ['v:f92acb5b-079a-42bc-913a-657f270a3dc1'], STARTROW => '000a', > LIMIT > > > => > > > > 1 > > > > > } > > > > > ROW > > > > > COLUMN+CELL > > > > > > > > > > 000a > > > > > column=v:f92acb5b-079a-42bc-913a-657f270a3dc1, > > timestamp=1432088038576, > > > > > > > > > > > > > > > value=\x08000aHf92acb5b-079a-42bc-913a-657f270a3dc1\x0EFAILURE\x0CNE-858\x > > > > > > > > > > > > > > > > > > > > > > > > > 140-0000-000\x02\x96\x01SXOAXTPSIUFPPNUCIEVQGCIZHCEJBKGWINHKIHFRHWHNATAHAHQBFRAYLOAMQEGKLNZIFM > > > > > 000a > > > > > 1 row(s) in 12.6720 seconds > > > > > > > > > > hbase(main):010:0> get 'sensors', '000a', {COLUMN => > > > > > 'v:f92acb5b-079a-42bc-913a-657f270a3dc1'} > > > > > COLUMN > > > > > CELL > > > > > > > > > > v:f92acb5b-079a-42bc-913a-657f270a3dc1 > > > > timestamp=1432088038576, > > > > > > > > > > > > > > > > > > > > value=\x08000aHf92acb5b-079a-42bc-913a-657f270a3dc1\x0EFAILURE\x0CNE-858\x140-0000-000\x02\x96\x01SXOAXTPSIUFPPNUCIEVQGCI > > > > > > > > > > ZHCEJBKGWINHKIHFRHWHNATAHAHQBFRAYLOAMQEGKLNZIFM > > > > > 000a > > > > > > > > > > 1 row(s) in 0.0280 seconds > > > > > > > > > > > > > > > They both return the same result. However, the get returns in 28ms > > > while > > > > > the scan returns in 12672ms. > > > > > > > > > > How come can the scan be that slow? Is it normal? If I remove the > QC > > > from > > > > > the scan, then it takes only 250ms to return all the columns. I > think > > > > > something is not correct. > > > > > > > > > > I'm running on 1.0.0-cdh5.4.0 so I guess it's the same for 1.0.x... > > > > > > > > > > JM > > > > > > > > > > > > > > >
