Fix various bugs with page compaction

Author: Alexander Korotkov

contrib/in_memory/btree.c

@@ -320,7 +320,7 @@ insert_to_leaf(BTreeStack *stack,
 			}
 			else
 			{
- 				int old_item_size = BTREE_PAGE_GET_ITEM_SIZE(p, offset);
+				int old_item_size = BTREE_PAGE_GET_ITEM_SIZE(p, offset);
 
 				/*
 				 * We should be able to undo this action without memory
@@ -679,6 +679,7 @@ btree_modify_internal(BTreeDescr *desc, BTreeModifyAction action,
 				}
 
 				undo_pos = preserve_undo_record(OLeafTupleHeaderSize);
+
 				if (!UndoPosIsValid(undo_pos))
 				{
 					unlock_page(p, state);

contrib/in_memory/btree_page.c

@@ -302,27 +302,12 @@ page_fits_item(Page p, OffsetNumber offset, LocationIndex size, bool replace)
 {
 	LocationIndex		free_space;
 	BTreePageHeader	   *header = (BTreePageHeader *) p;
+	LocationIndex		space_needed;
 	LocationIndex		vacated_bytes = header->nVacatedBytes;
 
 	Assert(size == MAXALIGN(size));
 
-	if (!replace)
-	{
-		free_space = page_get_free_space(p);
-
-		if (free_space < size + sizeof(OffsetNumber))
-		{
-			if (free_space + header->nVacatedBytes < size + sizeof(OffsetNumber))
-				return PageNotFit;
-			else
-				return PageFitAfterCompaction;
-		}
-		else
-		{
-			return PageFit;
-		}
-	}
-	else
+	if (replace)
 	{
 		LocationIndex		oldsize;
 		OLeafTupleHeader   *tupHdr;
@@ -343,19 +328,24 @@ page_fits_item(Page p, OffsetNumber offset, LocationIndex size, bool replace)
 		if (tupHdr->deleted && TX_IS_CSN(tupHdr->tx))
 			vacated_bytes -= oldsize - sizeof(OffsetNumber);
 
-		free_space = page_get_free_space(p);
+		space_needed = size - oldsize;
+	}
+	else
+	{
+		space_needed = size + sizeof(OffsetNumber);
+	}
 
-		if (free_space  < size - oldsize)
-		{
-			if (free_space + vacated_bytes < size - oldsize)
-				return PageNotFit;
-			else
-				return PageFitAfterCompaction;
-		}
+	free_space = page_get_free_space(p);
+	if (free_space < space_needed)
+	{
+		if (PAGE_IS_LEAF(p) && free_space + vacated_bytes >= space_needed)
+			return PageFitAfterCompaction;
 		else
-		{
-			return PageFit;
-		}
+			return PageNotFit;
+	}
+	else
+	{
+		return PageFit;
 	}
 }
 

contrib/in_memory/sql/tuple_limit.sql

@@ -4,4 +4,3 @@ INSERT INTO im_test1 VALUES (1, repeat('x', 281));
 INSERT INTO im_test1 VALUES (2, repeat('x', 289));
 INSERT INTO im_test1 SELECT id, repeat('x', 280) FROM generate_series(3, 1000) id;
 SELECT val, count(*) FROM im_test1 GROUP BY val;
-