I'm not sure. Throughout the test there is no split so it should not be HBASE-4335. Maybe HBASE-4334, where the client is confused and sends the request to a wrong region, but seeing that there is only one I can't see how this could be, even though the result I'm having is consistent with what is said in that issue.
On Mon, Oct 3, 2011 at 6:11 PM, Lars <[email protected]> wrote: > Might be related to HBASE-4335 > > Placido Revilla <[email protected]> schrieb: > > >Sorry, resent because I messed up the previous mail. > > > >Hi, > > > >we are experiencing a strange behavior in some tests we are currently > >performing. What we are seeing is that scans on a table that is being > >written to at the same time sometimes end prematurely, with no error. > >This seems to be heavily dependent on the write pattern. > > > >We've been able to reproduce the issue with the standard hbase tools: > > > >in a terminal run: > > > >OLDV=0; OLDT=0; while true; do NEWV=`hbase shell count_testtable | > >head -1 | cut -d' ' -f1`; NEWT=`date +%s`; echo $NEWV " -> " $(((NEWV > >- OLDV) / (NEWT - OLDT))) "msg/s"; OLDV=$NEWV; OLDT=$NEWT; done > > > >where the contents of the file count_testtable are: > > > >count 'TestTable', INTERVAL => 100000000, CACHE => 10000 > >exit > > > >This counts the rows in the TestTable repeatedly showing the number of > >rows and the delta rows per second inserted. In the hbase shell count > >is implemented as a full scan with a filter on the row key. > > > >Meanwhile, in another terminal do: > > > >hbase org.apache.hadoop.hbase.PerformanceEvaluation --nomapred > >--rows=20000 randomWrite 5 > > > >and when over: > > > >hbase org.apache.hadoop.hbase.PerformanceEvaluation --nomapred > >--rows=20000 sequentialWrite 5 > > > >On the scan terminal we are seeing results similar to: > > > >0 -> 0 msg/s > >45552 -> 5694 msg/s <=== randomWrite starts > >63284 -> 2955 msg/s > >63284 -> 0 msg/s <=== randomWrite ends > >58829 -> -636 msg/s <=== sequentialWrite starts > >88764 -> 3741 msg/s > >100000 -> 802 msg/s > >100000 -> 0 msg/s <=== sequentialWrite ends > > > >As you can see in the fifth row the count is lower than expected > >(resulting on a negative inserts/sec). > > > >You may need to try a couple of times or tweak the number of rows to > >insert to see the problem. > > > >hbase version: 0.90.4 (tried on a standalone and a full distributed > deployment). > > > >We think there must be an error somewhere or something we don't > >understand is slipping by us. > > > >Thanks. > > > >-- > >Plácido Revilla > >Senior Backend Engineer > >[email protected] > >TUENTI TECHNOLOGIES S.L. © > >PZA. DE LAS CORTES 2, 4ª PLANTA | 28014 MADRID > -- [image: Tuenti] <http://www.tuenti.com/> Plácido Revilla Senior Backend Engineer [email protected] TUENTI TECHNOLOGIES S.L. © PZA. DE LAS CORTES 2, 4ª PLANTA | 28014 MADRID
