Fix for valgrind

Valgrind doesn't take into account that mmap'ed memory might be shared.
This is why Valgrind reports false positives for memory which was undefined
in current process, but already overridden by another process.  The best thing
we can do is to evade writing undefined memory from any process.

Author: Alexander Korotkov

contrib/in_memory/btree.c

@@ -166,17 +166,17 @@ btree_split(BTreeDescr *desc, Page p, OffsetNumber *offset, bool *place_right,
 	if (*place_right)
 	{
 		if (!replace)
-			add_page_item(new_page, *offset, tuplesize + header_size);
+			add_page_item(new_page, *offset, MAXALIGN(tuplesize) + header_size);
 		else
-			resize_page_item(new_page, *offset, tuplesize + header_size);
+			resize_page_item(new_page, *offset, MAXALIGN(tuplesize) + header_size);
 		tuple_ptr = BTREE_PAGE_GET_ITEM(new_page, *offset);
 	}
 	else
 	{
 		if (!replace)
-			add_page_item(p, *offset, tuplesize + header_size);
+			add_page_item(p, *offset, MAXALIGN(tuplesize) + header_size);
 		else
-			resize_page_item(p, *offset, tuplesize + header_size);
+			resize_page_item(p, *offset, MAXALIGN(tuplesize) + header_size);
 		tuple_ptr = BTREE_PAGE_GET_ITEM(p, *offset);
 	}
 	memcpy(tuple_ptr, tupleheader, header_size);
@@ -188,7 +188,7 @@ btree_split(BTreeDescr *desc, Page p, OffsetNumber *offset, bool *place_right,
 	if (leaf)
 	{
 		rightbound_key = desc->tuple_make_key(desc, rightbound_key);
-		rightbound_key_size = MAXALIGN(desc->key_len(desc, rightbound_key));
+		rightbound_key_size = desc->key_len(desc, rightbound_key);
 	}
 	else
 	{
@@ -197,9 +197,9 @@ btree_split(BTreeDescr *desc, Page p, OffsetNumber *offset, bool *place_right,
 	}
 
 	if (was_rightmost)
-		add_page_item(p, BTREE_HIKEY, rightbound_key_size);
+		add_page_item(p, BTREE_HIKEY, MAXALIGN(rightbound_key_size));
 	else
-		resize_page_item(p, BTREE_HIKEY, rightbound_key_size);
+		resize_page_item(p, BTREE_HIKEY, MAXALIGN(rightbound_key_size));
 
 	memcpy(BTREE_PAGE_GET_ITEM(p, BTREE_HIKEY),
 		   rightbound_key, rightbound_key_size);
@@ -275,7 +275,8 @@ insert_to_leaf(BTreeStack *stack,
 
 	while (true)
 	{
-		PageFitsItemResult fit = page_fits_item(p, offset, tuplen + tupheaderlen, replace);
+		LocationIndex			itemsize = MAXALIGN(tuplen) + tupheaderlen;
+		PageFitsItemResult		fit = page_fits_item(p, offset, itemsize, replace);
 
 		if (fit != PageNotFit)
 		{
@@ -312,7 +313,7 @@ insert_to_leaf(BTreeStack *stack,
 			state = modify_page(p, state);
 			if (!replace)
 			{
-				add_page_item(p, offset, tuplen + tupheaderlen);
+				add_page_item(p, offset, itemsize);
 
 				/* Increment number of tuples in progress */
 				if (level == 0)
@@ -327,8 +328,8 @@ insert_to_leaf(BTreeStack *stack,
 				 * allocation.  Thus we shouldn't cut space occupied by this
 				 * page item.
 				 */
-				if (tuplen + tupheaderlen > old_item_size)
-					resize_page_item(p, offset, tuplen + tupheaderlen);
+				if (itemsize > old_item_size)
+					resize_page_item(p, offset, itemsize);
 
 				if (level == 0)
 				{
@@ -777,7 +778,7 @@ btree_modify_internal(BTreeDescr *desc, BTreeModifyAction action,
 		}
 	}
 
-	tuplen = MAXALIGN(desc->tuple_len(desc, tuple));
+	tuplen = desc->tuple_len(desc, tuple);
 	insert_to_leaf(&stack, tuple, tuplen, &leaf_header, replace, self_update, undo_pos);
 
 	return result;

contrib/in_memory/btree_page.c

@@ -19,6 +19,7 @@
 
 #include "access/transam.h"
 #include "storage/s_lock.h"
+#include "utils/memdebug.h"
 
 /* Page state flags */
 #define STATE_LOCKED_FLAG 1
@@ -103,6 +104,7 @@ unlock_page(Page p, uint32 state)
 		}
 	}
 
+	VALGRIND_CHECK_MEM_IS_DEFINED(GET_PAGE(pagenum), IN_MEMORY_BLCKSZ);
 	state = UNLOCK_STATE(state);
 	pg_write_barrier();
 	pg_atomic_write_u32(&header->state, state);

contrib/in_memory/btree_undo.c

@@ -57,14 +57,14 @@ apply_undo(BTreeDescr *desc, Page p, OffsetNumber offset, bool loop)
 
 		Pointer	prev_item = GET_UNDO_REC(tuphdr->undoPos);
 		Pointer	prev_tuple = prev_item + OLeafTupleHeaderSize;
-		int		prev_tuplen = MAXALIGN(desc->tuple_len(desc, prev_tuple));
-		int		prev_itemlen = prev_tuplen + OLeafTupleHeaderSize;
+		int		prev_tuplen = desc->tuple_len(desc, prev_tuple);
+		int		prev_itemlen = OLeafTupleHeaderSize + MAXALIGN(prev_tuplen);
 		OLeafTupleHeader *prev_header = (OLeafTupleHeader *) prev_item;
 
 		Assert(prev_itemlen <= BTREE_PAGE_GET_ITEM_SIZE(p, offset));
 		resize_page_item(p, offset, prev_itemlen);
 		item = BTREE_PAGE_GET_ITEM(p, offset);
-		memcpy(item, prev_item, prev_itemlen);
+		memcpy(item, prev_item, OLeafTupleHeaderSize + prev_tuplen);
 
 		/*
 		 * If previous version was committed then update number of in-progress