Hey David, With oracle, the BigDecimalSplitter will be used by default for all number types.
-Abe On Wed, Jun 19, 2013 at 4:05 PM, David Kincaid <[email protected]>wrote: > Abe, the database is Oracle. > > > On Wed, Jun 19, 2013 at 5:48 PM, Abraham Elmahrek <[email protected]>wrote: > >> David, >> >> What database are you importing from? The description I gave was for >> datatypes that map to the BigDecimal Splitter. The userguide might be >> referring to the IntegerSplitter which will add the remainder to the last >> value. >> >> -Abe >> >> >> On Wed, Jun 19, 2013 at 1:23 PM, David Kincaid <[email protected]>wrote: >> >>> Thanks. We didn't specify the number of mappers, so it's giving us 4. I >>> understand your explanation, but it seems to conflict with the Sqoop user >>> guide ( >>> http://sqoop.apache.org/docs/1.4.3/SqoopUserGuide.html#_controlling_parallelism >>> ): >>> >>> "When performing parallel imports, Sqoop needs a criterion by which it >>> can split the workload. Sqoop uses a *splitting column* to split the >>> workload. By default, Sqoop will identify the primary key column (if >>> present) in a table and use it as the splitting column. The low and high >>> values for the splitting column are retrieved from the database, and the >>> map tasks operate on evenly-sized components of the total range. For >>> example, if you had a table with a primary key column of id whose >>> minimum value was 0 and maximum value was 1000, and Sqoop was directed to >>> use 4 tasks, Sqoop would run four processes which each execute SQL >>> statements of the form SELECT * FROM sometable WHERE id >= lo AND id < >>> hi, with (lo, hi) set to (0, 250), (250, 500), (500, 750), and (750, >>> 1001) in the different tasks." >>> >>> >>> On Wed, Jun 19, 2013 at 3:14 PM, Abraham Elmahrek <[email protected]>wrote: >>> >>>> Hey David, >>>> >>>> Here's the algorithm: >>>> Split lengths are defined by (max - min)/(# mappers) and whatever is >>>> left is tacked on at the end. So in this case, (288272191-2110)/3 = >>>> 96090027.33... So I'm assuming the .33... is rounded down and split lengths >>>> will be of length 96090027. Sqoop will then create splits with the >>>> following points: (min) + (range length)*(n). We can see that 2110 + >>>> 96090027*0 >>>> = 2110, 2110 + 96090027*1 = 96092137, 2110 + 96090027*2 = 192182164, >>>> and 2110 + 96090027*3 = 288272191 will be generated based off of this >>>> algorithm. The last point to be added will be 288272192 because the >>>> max value is not part of the generated split points. Then sqoop will >>>> distributed accordingly based off of these points as you've pointed out >>>> above. >>>> >>>> Just to be sure, did you configure sqoop to use 3 mappers? >>>> >>>> Hope this helps, >>>> -Abe >>>> >>>> >>>> On Wed, Jun 19, 2013 at 8:33 AM, David Kincaid >>>> <[email protected]>wrote: >>>> >>>>> We're seeing a strange thing happen with a sqoop import job with the >>>>> way the key range is getting distributed among the 4 mappers that are >>>>> running. The minimum key value is 2110 and the maximum value is 288272191. >>>>> We are getting one mapper that is only getting one record to import. Here >>>>> is the distribution among the mappers: >>>>> >>>>> [2110, 96092137) >>>>> [96092137, 192182164) >>>>> [192182164, 288272191) >>>>> [288272191, 288272192) >>>>> >>>>> you can see that the fourth mapper is given a range with only one >>>>> value in it. Could someone help me understand what is going on? >>>>> >>>>> Thanks, >>>>> >>>>> Dave >>>>> >>>> >>>> >>> >> >
