Fix handling of variable-length tuples in in_memory FDW

Alexander Korotkov · Alexander Korotkov · commit 5e29378691f6 · 2018-05-11T00:05:50.000+03:00
Fix two bugs related to variable-length tuples:
1) It wasn't taken into account that when tuple was going to be replaced,
   after page compaction it might go away.
2) Whe deleted tuple is replaced, number of vacated bytes was mistakenly
   decreased by size of new tuple instead of old tuple.
diff --git a/contrib/in_memory/btree.c b/contrib/in_memory/btree.c
@@ -286,6 +286,27 @@ insert_to_leaf(BTreeStack *stack,
 			{
 				compact_page(desc, p, &state);
 				offset = btree_page_binary_search(desc, p, tuple, BTreeTuple);
+
+				/*
+				 * If we were going to replace the tuple, then we should check
+				 * it's not gone after compaction.
+				 */
+				if (replace)
+				{
+					Assert(PAGE_IS_LEAF(p)); /* We place tuples only on leaf pages */
+
+					if (offset < header->itemsCount)
+					{
+						Pointer curTuple = BTREE_PAGE_GET_ITEM(p, offset) +
+										   OLeafTupleHeaderSize;
+						if (desc->cmp(desc, tuple, BTreeTuple, curTuple, BTreeTuple))
+							replace = false;
+					}
+					else
+					{
+						replace = false;
+					}
+				}
 			}
 
 			state = modify_page(p, state);
@@ -299,12 +320,14 @@ insert_to_leaf(BTreeStack *stack,
 			}
 			else
 			{
+ 				int old_item_size = BTREE_PAGE_GET_ITEM_SIZE(p, offset);
+
 				/*
 				 * We should be able to undo this action without memory
 				 * allocation.  Thus we shouldn't cut space occupied by this
 				 * page item.
 				 */
-				if (tuplen + tupheaderlen > BTREE_PAGE_GET_ITEM_SIZE(p, offset))
+				if (tuplen + tupheaderlen > old_item_size)
 					resize_page_item(p, offset, tuplen + tupheaderlen);
 
 				if (level == 0)
@@ -324,8 +347,8 @@ insert_to_leaf(BTreeStack *stack,
 						 * tuple.
 						 */
 						if (prev->deleted)
-							header->nVacatedBytes -= BTREE_PAGE_GET_ITEM_SIZE(p, offset)
-													 + sizeof(OffsetNumber);
+							header->nVacatedBytes -= (old_item_size
+													  + sizeof(OffsetNumber));
 					}
 				}
 			}
diff --git a/contrib/in_memory/btree_page.c b/contrib/in_memory/btree_page.c
@@ -302,6 +302,7 @@ page_fits_item(Page p, OffsetNumber offset, LocationIndex size, bool replace)
 {
 	LocationIndex		free_space;
 	BTreePageHeader	   *header = (BTreePageHeader *) p;
+	LocationIndex		vacated_bytes = header->nVacatedBytes;
 
 	Assert(size == MAXALIGN(size));
 
@@ -323,19 +324,30 @@ page_fits_item(Page p, OffsetNumber offset, LocationIndex size, bool replace)
 	}
 	else
 	{
-		LocationIndex oldsize;
+		LocationIndex		oldsize;
+		OLeafTupleHeader   *tupHdr;
 
+		Assert(PAGE_IS_LEAF(p));
 		oldsize = BTREE_PAGE_GET_ITEM_SIZE(p, offset);
 		Assert(oldsize == MAXALIGN(oldsize));
 
 		if (size <= oldsize)
 			return PageFit;
 
+		/*
+		 * If replaced tuple will go away after page compaction, then
+		 * we should substract the size occupied by it from the size to
+		 * be freed by page compaction.
+		 */
+		tupHdr = (OLeafTupleHeader *) BTREE_PAGE_GET_ITEM(p, offset);
+		if (tupHdr->deleted && TX_IS_CSN(tupHdr->tx))
+			vacated_bytes -= oldsize - sizeof(OffsetNumber);
+
 		free_space = page_get_free_space(p);
 
 		if (free_space  < size - oldsize)
 		{
-			if (free_space + header->nVacatedBytes < size - oldsize)
+			if (free_space + vacated_bytes < size - oldsize)
 				return PageNotFit;
 			else
 				return PageFitAfterCompaction;
diff --git a/contrib/in_memory/expected/in_memory.out b/contrib/in_memory/expected/in_memory.out
@@ -5531,3 +5531,69 @@ SELECT * FROM test10 JOIN im_test13 USING(idi, idv);
 
 set enable_nestloop=on;
 set enable_hashjoin=on;
+-- wrong nVacatedBytes bug
+TRUNCATE im_test1;
+INSERT INTO im_test1 VALUES (1, repeat('x', 200));
+DELETE FROM im_test1 WHERE id = 1;
+INSERT INTO im_test1 SELECT id, repeat('x', 250) FROM generate_series(1, 4) id;
+SELECT * FROM im_test1;
+ id |                                                                                                                            val                                                                                                                             
+----+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+  1 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  2 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  3 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  4 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+(4 rows)
+
+--- replace item when page itemsCount == 0 bug
+-- exact recipe
+TRUNCATE im_test1;
+INSERT INTO im_test1 SELECT id, repeat('x', 200) FROM generate_series(1, 10) id;
+DELETE FROM im_test1 WHERE id > 0;
+INSERT INTO im_test1 SELECT id, repeat('x', 250) FROM generate_series(7, 7) id;
+SELECT * FROM im_test1;
+ id |                                                                                                                            val                                                                                                                             
+----+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+  7 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+(1 row)
+
+TRUNCATE im_test1;
+INSERT INTO im_test1 SELECT id, repeat('x', 200) FROM generate_series(1, 100) id;
+DELETE FROM im_test1 WHERE id > 0;
+INSERT INTO im_test1 SELECT id, repeat('x', 250) FROM generate_series(1, 100) id;
+SELECT count(*), sum(id) FROM im_test1;
+ count | sum  
+-------+------
+   100 | 5050
+(1 row)
+
+-- replace deleted item after compaction
+TRUNCATE im_test1;
+INSERT INTO im_test1 SELECT id, repeat('x', 200) FROM generate_series(1, 10) id;
+DELETE FROM im_test1 WHERE id % 2 = 0;
+INSERT INTO im_test1 SELECT id, repeat('x', 250) FROM generate_series(2, 10, 2) id;
+SELECT * FROM im_test1;
+ id |                                                                                                                            val                                                                                                                             
+----+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+  1 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  2 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  3 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  4 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  5 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  6 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  7 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  8 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  9 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+ 10 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+(10 rows)
+
+TRUNCATE im_test1;
+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;
+ count | sum  
+-------+------
+   100 | 5050
+(1 row)
+
diff --git a/contrib/in_memory/expected/in_memory_1.out b/contrib/in_memory/expected/in_memory_1.out
@@ -5395,3 +5395,69 @@ SELECT * FROM test10 JOIN im_test13 USING(idi, idv);
 
 set enable_nestloop=on;
 set enable_hashjoin=on;
+-- wrong nVacatedBytes bug
+TRUNCATE im_test1;
+INSERT INTO im_test1 VALUES (1, repeat('x', 200));
+DELETE FROM im_test1 WHERE id = 1;
+INSERT INTO im_test1 SELECT id, repeat('x', 250) FROM generate_series(1, 4) id;
+SELECT * FROM im_test1;
+ id |                                                                                                                            val                                                                                                                             
+----+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+  1 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  2 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  3 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  4 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+(4 rows)
+
+--- replace item when page itemsCount == 0 bug
+-- exact recipe
+TRUNCATE im_test1;
+INSERT INTO im_test1 SELECT id, repeat('x', 200) FROM generate_series(1, 10) id;
+DELETE FROM im_test1 WHERE id > 0;
+INSERT INTO im_test1 SELECT id, repeat('x', 250) FROM generate_series(7, 7) id;
+SELECT * FROM im_test1;
+ id |                                                                                                                            val                                                                                                                             
+----+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+  7 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+(1 row)
+
+TRUNCATE im_test1;
+INSERT INTO im_test1 SELECT id, repeat('x', 200) FROM generate_series(1, 100) id;
+DELETE FROM im_test1 WHERE id > 0;
+INSERT INTO im_test1 SELECT id, repeat('x', 250) FROM generate_series(1, 100) id;
+SELECT count(*), sum(id) FROM im_test1;
+ count | sum  
+-------+------
+   100 | 5050
+(1 row)
+
+-- replace deleted item after compaction
+TRUNCATE im_test1;
+INSERT INTO im_test1 SELECT id, repeat('x', 200) FROM generate_series(1, 10) id;
+DELETE FROM im_test1 WHERE id % 2 = 0;
+INSERT INTO im_test1 SELECT id, repeat('x', 250) FROM generate_series(2, 10, 2) id;
+SELECT * FROM im_test1;
+ id |                                                                                                                            val                                                                                                                             
+----+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+  1 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  2 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  3 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  4 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  5 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  6 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  7 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  8 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+  9 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+ 10 | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+(10 rows)
+
+TRUNCATE im_test1;
+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;
+ count | sum  
+-------+------
+   100 | 5050
+(1 row)
+
diff --git a/contrib/in_memory/expected/in_memory_2.out b/contrib/in_memory/expected/in_memory_2.out
diff --git a/contrib/in_memory/sql/in_memory.sql b/contrib/in_memory/sql/in_memory.sql
