To your question regarding if you can write a mapper that sends only the columns that you need:
Yes of course you can do it. See the example in Importer.java. It shows you how a simple copytable can be implemented. Use a similar way but before creating the new put for the new table, just check the KVs and then decide. Hope this helps. Regards Ram On Sat, Feb 9, 2013 at 7:52 AM, Ted Yu <[email protected]> wrote: > See the following javadoc in Scan.java: > > * To only retrieve columns within a specific range of version timestamps, > > * execute {@link #setTimeRange(long, long) setTimeRange}. > You can search for the above method in unit tests. > > In your use case, is family f the only family ? > If not, take a look at HBASE-5416 which is coming in 0.94.5 > family f would be the essential column. > > Cheers > > On Fri, Feb 8, 2013 at 5:47 PM, <[email protected]> wrote: > > > Hi, > > > > Thanks for suggestions. How a time range scan can be implemented in java > > code. Is there any sample code or tutorials? > > Also, is it possible to select by a value of a column? Let say I know > that > > records has family f and column m, and new records has m=5. I need to > > instruct hbase to send only these records to the mapper of mapred jobs. > > > > Thanks. > > Alex. > > > > > > > > > > > > > > > > -----Original Message----- > > From: Ted Yu <[email protected]> > > To: user <[email protected]> > > Sent: Fri, Feb 8, 2013 11:05 am > > Subject: Re: split table data into two or more tables > > > > > > bq. in a cluster of 2 nodes +1 master > > I assume you're limited by hardware in the regard. > > > > bq. job selects these new records > > Have you used time-range scan ? > > > > Cheers > > > > On Fri, Feb 8, 2013 at 10:59 AM, <[email protected]> wrote: > > > > > Hi, > > > > > > The rationale is that I have a mapred job that adds new records to an > > > hbase table, constantly. > > > The next mapred job selects these new records, but it must iterate over > > > all records and check if it is a candidate for selection. > > > Since there are too many old records iterating though them in a cluster > > of > > > 2 nodes +1 master takes about 2 days. So I thought, splitting them into > > two > > > tables must reduce this time, and as soon as I figure out that there is > > no > > > more new record left in one of the new tables I will not run mapred job > > on > > > it. > > > > > > Currently, we have 7 regions including ROOT and META. > > > > > > > > > Thanks. > > > Alex. > > > > > > > > > > > > > > > > > > > > > -----Original Message----- > > > From: Ted Yu <[email protected]> > > > To: user <[email protected]> > > > Sent: Fri, Feb 8, 2013 10:40 am > > > Subject: Re: split table data into two or more tables > > > > > > > > > May I ask the rationale behind this ? > > > Were you aiming for higher write throughput ? > > > > > > Please also tell us how many regions you have in the current table. > > > > > > Thanks > > > > > > BTW please consider upgrading to 0.94.4 > > > > > > On Fri, Feb 8, 2013 at 10:36 AM, <[email protected]> wrote: > > > > > > > Hello, > > > > > > > > I wondered if there is a way of splitting data from one table into > two > > or > > > > more tables in hbase with iidentical schemas, i.e. if table A has > 100M > > > > records put 50M into table B, 50M into table C and delete table A. > > > > Currently, I use hbase-0.92.1 and hadoop-1.4.0 > > > > > > > > Thanks. > > > > Alex. > > > > > > > > > > > > > > > > > > > >
