Anil: As code #3 shows, having stopRow helps narrow the range of rows participating in aggregation.
Do you have suggestion on how this process can be made more user-friendly ? Thanks On Mon, May 14, 2012 at 1:47 PM, anil gupta <[email protected]> wrote: > HI Ted, > > My bad, i missed out a big difference between the Scan object i am using in > my filter and Scan object used in coprocessors. So, scan object is not > same. > Basically, i am doing filtering on the basis of a prefix of RowKey. > > So, in my filter i do this to build scanner: > Code 1: > Filter filter = new PrefixFilter(Bytes.toBytes(strPrefix)); > Scan scan = new Scan(); > scan.setFilter(filter); > scan.setStartRow(Bytes.toBytes(strPrefix)); // I dont set any > stopRow in this scanner. > > In coprocessor, i do the following for scanner: > Code 2: > Scan scan = new Scan(); > scan.setFilter(new PrefixFilter(Bytes.toBytes(prefix))); > > I dont have startRow in above code because if i only use only the startRow > in coprocessor scanner then i get the following exception(due to this I > removed the startRow from CP scan object code): > java.io.IOException: Agg client Exception: Startrow should be smaller than > Stoprow > at > > org.apache.hadoop.hbase.client.coprocessor.AggregationClient.validateParameters(AggregationClient.java:116) > at > > org.apache.hadoop.hbase.client.coprocessor.AggregationClient.max(AggregationClient.java:85) > at > com.intuit.ihub.hbase.poc.DummyClass.doAggregation(DummyClass.java:81) > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > at > > sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) > > > I modified the above code#2 to add the stopRow also: > Code 3: > Scan scan = new Scan(); > scan.setStartRow(Bytes.toBytes(prefix)); > > scan.setStopRow(Bytes.toBytes(String.valueOf(Long.parseLong(prefix)+1))); > scan.setFilter(new PrefixFilter(Bytes.toBytes(prefix))); > > When, i run the coprocessor with Code #3, its blazing fast. I gives the > result in around 200 millisecond. :) > Since, this was just testing a coprocessors i added the logic to add the > stopRow manually. What is the reason that Scan object in coprocessor always > requires stopRow along with startRow?(code #1 works fine even when i dont > use stopRow) Can this restriction be relaxed? > > Thanks, > Anil Gupta > > > > On Mon, May 14, 2012 at 12:55 PM, Ted Yu <[email protected]> wrote: > > > Anil: > > I think the performance was related to your custom filter. > > > > Please tell us more about the filter next time. > > > > Thanks > > > > On Mon, May 14, 2012 at 12:31 PM, anil gupta <[email protected]> > > wrote: > > > > > HI Stack, > > > > > > I'll look into Gary Helming post and try to do profiling of coprocessor > > and > > > share the results. > > > > > > Thanks, > > > Anil Gupta > > > > > > On Mon, May 14, 2012 at 12:08 PM, Stack <[email protected]> wrote: > > > > > > > On Mon, May 14, 2012 at 12:02 PM, anil gupta <[email protected]> > > > > wrote: > > > > > I loaded around 70 thousand 1-2KB records in HBase. For scans, with > > my > > > > > custom filter i am able to get 97 rows in 500 milliseconds and for > > > doing > > > > > sum, max, min(in built aggregations of HBase) on the same custom > > filter > > > > its > > > > > taking 11000 milliseconds. Does this mean that coprocessors > > aggregation > > > > is > > > > > supposed to be around ~20x slower than scans? Am i missing any > trick > > > over > > > > > here? > > > > > > > > > > > > > That seems like a high tax to pay for running CPs. Can you dig in on > > > > where the time is being spent? (See another recent note on this list > > > > or on dev where Gary Helmling talks about how he did basic profiling > > > > of CPs). > > > > St.Ack > > > > > > > > > > > > > > > > -- > > > Thanks & Regards, > > > Anil Gupta > > > > > > > > > -- > Thanks & Regards, > Anil Gupta >
