From 1a47d44891c50e406fb3e1d9ca4bc0f536782a2a Mon Sep 17 00:00:00 2001
From: amit <amitlangote09@gmail.com>
Date: Wed, 28 Dec 2016 10:10:26 +0900
Subject: [PATCH 2/8] Set ecxt_scantuple correctly for tuple-routing

In 2ac3ef7a01df859c62d0a02333b646d65eaec5ff, we changed things so that
it's possible for a different TupleTableSlot to be used for partitioned
tables at successively lower levels.  If we do end up changing the slot
from the original, we must update ecxt_scantuple to point to the new one
for partition key of the tuple to be computed correctly.

Also update the regression tests so that the code manipulating
ecxt_scantuple is covered.

Reported by: Rajkumar Raghuwanshi
Patch by: Amit Langote
Reports: https://www.postgresql.org/message-id/CAKcux6%3Dm1qyqB2k6cjniuMMrYXb75O-MB4qGQMu8zg-iGGLjDw%40mail.gmail.com
---
 src/backend/catalog/partition.c      | 29 ++++++++++++++++++++++-------
 src/backend/executor/execMain.c      |  2 --
 src/test/regress/expected/insert.out |  2 +-
 src/test/regress/sql/insert.sql      |  2 +-
 4 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/src/backend/catalog/partition.c b/src/backend/catalog/partition.c
index 874e69d8d6..e540fc16d0 100644
--- a/src/backend/catalog/partition.c
+++ b/src/backend/catalog/partition.c
@@ -1642,7 +1642,10 @@ get_partition_for_tuple(PartitionDispatch *pd,
 	bool		isnull[PARTITION_MAX_KEYS];
 	int			cur_offset,
 				cur_index;
-	int			i;
+	int			i,
+				result;
+	ExprContext *ecxt = GetPerTupleExprContext(estate);
+	TupleTableSlot *ecxt_scantuple_old = ecxt->ecxt_scantuple;
 
 	/* start with the root partitioned table */
 	parent = pd[0];
@@ -1671,7 +1674,14 @@ get_partition_for_tuple(PartitionDispatch *pd,
 			slot = myslot;
 		}
 
-		/* Extract partition key from tuple */
+		/*
+		 * Extract partition key from tuple; FormPartitionKeyDatum() expects
+		 * ecxt_scantuple to point to the correct tuple slot (which might be
+		 * different from the slot we received from the caller if the
+		 * partitioned table of the current level has different tuple
+		 * descriptor from its parent).
+		 */
+		ecxt->ecxt_scantuple = slot;
 		FormPartitionKeyDatum(parent, slot, estate, values, isnull);
 
 		if (key->strategy == PARTITION_STRATEGY_RANGE)
@@ -1726,16 +1736,21 @@ get_partition_for_tuple(PartitionDispatch *pd,
 		 */
 		if (cur_index < 0)
 		{
+			result = -1;
 			*failed_at = RelationGetRelid(parent->reldesc);
-			return -1;
+			break;
 		}
-		else if (parent->indexes[cur_index] < 0)
-			parent = pd[-parent->indexes[cur_index]];
-		else
+		else if (parent->indexes[cur_index] >= 0)
+		{
+			result = parent->indexes[cur_index];
 			break;
+		}
+		else
+			parent = pd[-parent->indexes[cur_index]];
 	}
 
-	return parent->indexes[cur_index];
+	ecxt->ecxt_scantuple = ecxt_scantuple_old;
+	return result;
 }
 
 /*
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 5457f8fbde..67e46729f3 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -3191,9 +3191,7 @@ ExecFindPartition(ResultRelInfo *resultRelInfo, PartitionDispatch *pd,
 {
 	int		result;
 	Oid		failed_at;
-	ExprContext *econtext = GetPerTupleExprContext(estate);
 
-	econtext->ecxt_scantuple = slot;
 	result = get_partition_for_tuple(pd, slot, estate, &failed_at);
 	if (result < 0)
 	{
diff --git a/src/test/regress/expected/insert.out b/src/test/regress/expected/insert.out
index 729d9ebbbc..b8e74caee8 100644
--- a/src/test/regress/expected/insert.out
+++ b/src/test/regress/expected/insert.out
@@ -320,7 +320,7 @@ drop table part_ee_ff, part_gg2_2, part_gg2_1, part_gg2, part_gg1, part_gg;
 drop table part_aa_bb, part_cc_dd, part_null, list_parted;
 -- more tests for certain multi-level partitioning scenarios
 create table p (a int, b int) partition by range (a, b);
-create table p1 (b int, a int not null) partition by range (b);
+create table p1 (b int not null, a int not null) partition by range ((b+0));
 create table p11 (like p1);
 alter table p11 drop a;
 alter table p11 add a int;
diff --git a/src/test/regress/sql/insert.sql b/src/test/regress/sql/insert.sql
index 5509555fc5..2154d01c56 100644
--- a/src/test/regress/sql/insert.sql
+++ b/src/test/regress/sql/insert.sql
@@ -193,7 +193,7 @@ drop table part_aa_bb, part_cc_dd, part_null, list_parted;
 
 -- more tests for certain multi-level partitioning scenarios
 create table p (a int, b int) partition by range (a, b);
-create table p1 (b int, a int not null) partition by range (b);
+create table p1 (b int not null, a int not null) partition by range ((b+0));
 create table p11 (like p1);
 alter table p11 drop a;
 alter table p11 add a int;
-- 
2.11.0