From 1c6856b20e51c91eed0d2fd4e040d1df2ca2d21d Mon Sep 17 00:00:00 2001
From: amit <amitlangote09@gmail.com>
Date: Fri, 10 May 2019 13:52:59 +0900
Subject: [PATCH 2/2] Bug fix

---
 src/backend/partitioning/partprune.c          | 28 ++++++++++++++++++++++-----
 src/test/regress/expected/partition_prune.out |  4 +++-
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/src/backend/partitioning/partprune.c b/src/backend/partitioning/partprune.c
index b5c1c7d4dd..f6da2a8b2c 100644
--- a/src/backend/partitioning/partprune.c
+++ b/src/backend/partitioning/partprune.c
@@ -3103,11 +3103,29 @@ perform_pruning_base_step(PartitionPruneContext *context,
 											opstep->nullkeys);
 
 		case PARTITION_STRATEGY_RANGE:
-			return get_matching_range_bounds(context,
-											 opstep->opstrategy,
-											 values, nvalues,
-											 partsupfunc,
-											 opstep->nullkeys);
+			{
+				int		opstrategy = opstep->opstrategy;
+
+				/*
+				 * If we got values for only a subset (prefix) of the
+				 * expressions in opstep->exprs, adjust the strategy to
+				 * be used for pruning.  Originally, it would be the strategy
+				 * of the operator comparing the *last* expression against the
+				 * corresponding partition key, but it would be wrong to use
+				 * the same strategy now that we'll be comparing the values of
+				 * only a prefix of expressions against the partition bounds.
+				 * Use equality strategy, because all expressions in the
+				 * prefix must have been extracted from clauses containing
+				 * equality (=) or inclusive operators (<=, >=) anyway.
+				 */
+				if (nvalues < list_length(opstep->exprs))
+					opstrategy = BTEqualStrategyNumber;
+				return get_matching_range_bounds(context,
+												 opstrategy,
+												 values, nvalues,
+												 partsupfunc,
+												 opstep->nullkeys);
+			}
 
 		default:
 			elog(ERROR, "unexpected partition strategy: %d",
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index c8cd6a23f1..c26a86472a 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -951,9 +951,11 @@ explain (costs off) select * from mc3p where a = 1 and abs(b) < (select 2);
      ->  Result
    ->  Seq Scan on mc3p0
          Filter: ((a = 1) AND (abs(b) < $0))
+   ->  Seq Scan on mc3p1
+         Filter: ((a = 1) AND (abs(b) < $0))
    ->  Seq Scan on mc3p_default
          Filter: ((a = 1) AND (abs(b) < $0))
-(7 rows)
+(9 rows)
 
 -- a simpler multi-column keys case
 create table mc2p (a int, b int) partition by range (a, b);
-- 
2.11.0