Hi Nitin/Prasan, Thanks for your replies, I appreciate your help :)
Clustering looks to be quite close to what we want. However one main gap is that we need to fire hive query to populate clusters. In our case, the clustered data is already there. So computation in Hive query would be redundant. If CREATE TABLE analyze (generated_by INT, other_representative_field INT) PARTITIONED BY (dt STRING) CLUSTERED BY (generated_by) INTO 100 BUCKETS; Just accepts s3 directory hierarchy that we have (as explained in first mail), our problem would be solved. Another interesting solutions seem to be creating partition on dt field and creating Hive index/view on *generated_by *field. If anyone has insights around these, they would be really helpful. Meanwhile we will try to solve our problem by buckets/indices. -- Regards, Saumitra Shahapure On Tue, Mar 25, 2014 at 7:44 PM, Prasan Samtani <prasan.samt...@hulu.com>wrote: > Hi Saumitra, > > You might want to look into clustering within the partition. That is, > partition by "day", but cluster by "generated by" (within those > partitions), and see if that improves performance. Refer to the CLUSTER BY > command in the Hive language Manual. > > -Prasan > > > On Mar 25, 2014, at 4:26 AM, "Saumitra Shahapure (Vizury)" < > saumitra.shahap...@vizury.com> wrote: > > Hi Nitin, > > We are not facing small files problem since data is in S3. Also we do not > want to merge files. Merging files are creating large analyze table for say > one day would slow down queries fired on specific day and *generated_by.* > > Let me explain my problem in other words. > Right now we are over-partitioning our table. Over-partitioning is giving > us benefit that query on 1-2 partitions is too fast. It's side-effect is > that If we try to query large number of partitions, query is too slow. Is > there a way to get good performance in both of the scenarios? > > -- > Regards, > Saumitra Shahapure > > > On Tue, Mar 25, 2014 at 4:25 PM, Nitin Pawar <nitinpawar...@gmail.com>wrote: > >> see if this is what you are looking for >> https://github.com/sskaje/hive_merge >> >> >> >> >> On Tue, Mar 25, 2014 at 4:21 PM, Saumitra Shahapure (Vizury) < >> saumitra.shahap...@vizury.com> wrote: >> >>> Hello, >>> >>> We are using Hive to query S3 data. For one of our tables named analyze, >>> we generate data hierarchically. First level of hierarchy is date and >>> second level is a field named *generated_by*. e.g. for 20 march we may >>> have S3 directories as >>> s3://analyze/20140320/111/ >>> s3://analyze/20140320/222/ >>> s3://analyze/20140320/333/ >>> Size of files in each folders is typically small. >>> >>> Till now we have been using static partitioning so that queries on >>> specific date and *generated_by* would be faster. >>> >>> Now problem is that number of *generated_by* folders is increased to >>> 1000s. Everyday we end up adding 1000s of partitions to Hive. So queries on >>> analyze on one month are slowed down. >>> >>> Is there any way to get rid of partitions, and at the same time maintain >>> good performance of queries which are fired on specific day and >>> *generated_by*? >>> -- >>> Regards, >>> Saumitra Shahapure >>> >> >> >> >> -- >> Nitin Pawar >> > >
