Bug on delete/insert of the same key in the same transaction.

Author: Alexander Korotkov

contrib/in_memory/btree.c

@@ -721,6 +721,12 @@ btree_modify_internal(BTreeDescr *desc, BTreeModifyAction action,
 				{
 					/* If we deleted it ourselves, revert this deletion */
 					apply_undo(desc, p, offset, false);
+
+					/*
+					 * We've already reverted the previous delete, so don't
+					 * consider it as sefl update anymore.
+					 */
+					self_update = NoSelfUpdate;
 				}
 				replace = true;
 			}

contrib/in_memory/expected/in_memory.out

@@ -5216,3 +5216,18 @@ SELECT count(*), sum(id) FROM im_test1;
    100 | 5050
 (1 row)
 
+-- delete/insert of same key in the same transaction bug
+TRUNCATE im_test1;
+INSERT INTO im_test1 SELECT id, repeat('x', 280) FROM generate_series(1, 3) id;
+BEGIN;
+DELETE FROM im_test1 WHERE id = 3;
+INSERT INTO im_test1 SELECT id, repeat('x', 280) FROM generate_series(3, 4) id;
+ROLLBACK;
+SELECT * FROM im_test1;
+ id |                                                                                                                                           val                                                                                                                                            
+----+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+  1 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  2 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  3 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+(3 rows)
+

contrib/in_memory/sql/in_memory.sql

@@ -711,3 +711,12 @@ INSERT INTO im_test1 SELECT id, repeat('x', 200) FROM generate_series(1, 100) id
 DELETE FROM im_test1 WHERE id % 2 = 0;
 INSERT INTO im_test1 SELECT id, repeat('x', 250) FROM generate_series(2, 100, 2) id;
 SELECT count(*), sum(id) FROM im_test1;
+
+-- delete/insert of same key in the same transaction bug
+TRUNCATE im_test1;
+INSERT INTO im_test1 SELECT id, repeat('x', 280) FROM generate_series(1, 3) id;
+BEGIN;
+DELETE FROM im_test1 WHERE id = 3;
+INSERT INTO im_test1 SELECT id, repeat('x', 280) FROM generate_series(3, 4) id;
+ROLLBACK;
+SELECT * FROM im_test1;