On Thu, Jul 20, 2017 at 11:46 AM, Amit Langote <langote_amit...@lab.ntt.co.jp> wrote: > On 2017/07/20 15:05, Ashutosh Bapat wrote: >> On Wed, Jul 19, 2017 at 9:54 AM, Rafia Sabih >> <rafia.sa...@enterprisedb.com> wrote: >>> >>> Partition information: >>> Type of partitioning - single column range partition >>> Tables partitioned - Lineitem and orders >>> >>> Lineitem - >>> Partition key = l_orderkey >>> No of partitions = 18 >>> >>> Orders - >>> Partition key = o_orderkey >>> No of partitions = 11 >>> >> >> The patch set upto 0015 would refuse to join two partitioned relations >> using a partition-wise join if they have different number of >> partitions. Next patches implement a more advanced partition matching >> algorithm only for list partitions. Those next patches would refuse to >> apply partition-wise join for range partitioned tables. So, I am >> confused as to how come partition-wise join is being chosen even when >> the number of partitions differ. > > In 21_part_patched.out, I see that lineitem is partitionwise-joined with > itself. > > > Append > > -> Hash Semi Join > Hash Cond: (l1.l_orderkey = l2.l_orderkey) > Join Filter: (l2.l_suppkey <> l1.l_suppkey) > Rows Removed by Join Filter: 395116 > > -> Parallel Seq Scan on lineitem_001 l1 > Filter: (l_receiptdate > l_commitdate) > Rows Removed by Filter: 919654 > > -> Hash > Buckets: 8388608 Batches: 1 Memory Usage: 358464kB > -> Seq Scan on lineitem_001 l2 > Ah, I see now.
We need the same number of partitions in all partitioned tables, for joins to pick up partition-wise join. -- Best Wishes, Ashutosh Bapat EnterpriseDB Corporation The Postgres Database Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
