Allow left join removals and unique joins on partitioned tables

This allows left join removals and unique joins to work with partitioned
tables.  The planner just lacked sufficient proofs that a given join
would not cause any row duplication.  Unique indexes currently serve as
that proof, so have get_relation_info() populate the indexlist for
partitioned tables too.

Author: Arne Roland
Reviewed-by: Alvaro Herrera, Zhihong Yu, Amit Langote, David Rowley
Discussion: https://postgr.es/m/c3b2408b7a39433b8230bbcd02e9f302@index.de

1 files changed, 10 insertions, 0 deletions

diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index 3ddea3b683..c2b85d2795 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -4860,6 +4860,16 @@ select 1 from (select a.id FROM a left join b on a.b_id = b.id) q,
          Filter: (a.id = i)
 (4 rows)
 
+CREATE TEMP TABLE parted_b (id int PRIMARY KEY) partition by range(id);
+CREATE TEMP TABLE parted_b1 partition of parted_b for values from (0) to (10);
+-- test join removals on a partitioned table
+explain (costs off)
+select a.* from a left join parted_b pb on a.b_id = pb.id;
+  QUERY PLAN   
+---------------
+ Seq Scan on a
+(1 row)
+
 rollback;
 create temp table parent (k int primary key, pd int);
 create temp table child (k int unique, cd int);