Partition : Append node over a single SeqScan

Hi All,

Today while exploring a bit on Range table partitioning, I could see
that even if scan is performed on a single partition, the plan node
has Append node in it. Isn't it a bug?

As per the usage of Append Node, it should only be seen in the
queryplan when scan is performed on multiple tables.

Following are the steps to reproduce the problem.

CREATE TABLE part_tab (c1 int, c2 int) PARTITION BY RANGE (c1);

CREATE TABLE part1 PARTITION OF part_tab FOR VALUES FROM (0) TO (100);

CREATE TABLE part2 PARTITION OF part_tab FOR VALUES FROM (100) TO (200);

postgres=# explain analyze select * from part_tab where c1 > 100;
QUERY PLAN
--------------------------------------------------------------------------------------------------------
Append (cost=0.00..38.25 rows=753 width=8) (actual time=0.009..0.009
rows=0 loops=1)
-> Seq Scan on part2 (cost=0.00..38.25 rows=753 width=8) (actual
time=0.009..0.009 rows=0 loops=1)
Filter: (c1 > 100)
Planning time: 166698.973 ms
Execution time: 0.043 ms
(5 rows)

--
With Regards,
Ashutosh Sharma
EnterpriseDB:http://www.enterprisedb.com