branches/zip: Improve Valgrind instrumentation of the file-based merge sort

in fast index creation.

row_merge_write_eof(), row_merge_buf_write(): When UNIV_DEBUG_VALGRIND
is defined, fill the rest of the block (after the end-of-block marker)
with 0xff.

row/row0merge.c

@@ -437,7 +437,7 @@ row_merge_buf_write(
 #ifdef UNIV_DEBUG_VALGRIND
 	/* The rest of the block is uninitialized.  Initialize it
 	to avoid bogus warnings. */
-	memset(b, 0, block[1] - b);
+	memset(b, 0xff, block[1] - b);
 #endif /* UNIV_DEBUG_VALGRIND */
 }
 
@@ -776,7 +776,7 @@ row_merge_write_rec(
 			return(NULL);
 		}
 
-		UNIV_MEM_ALLOC(block[0], sizeof block[0]);
+		UNIV_MEM_INVALID(block[0], sizeof block[0]);
 
 		/* Copy the rest. */
 		b = block[0];
@@ -811,13 +811,17 @@ row_merge_write_eof(
 	*b++ = 0;
 	UNIV_MEM_ASSERT_RW(block[0], b - block[0]);
 	UNIV_MEM_ASSERT_W(block[0], sizeof block[0]);
-	UNIV_MEM_VALID(block[0], sizeof block[0]);
+#ifdef UNIV_DEBUG_VALGRIND
+	/* The rest of the block is uninitialized.  Initialize it
+	to avoid bogus warnings. */
+	memset(b, 0xff, block[1] - b);
+#endif /* UNIV_DEBUG_VALGRIND */
 
 	if (!row_merge_write(fd, (*foffs)++, block)) {
 		return(NULL);
 	}
 
-	UNIV_MEM_ALLOC(block[0], sizeof block[0]);
+	UNIV_MEM_INVALID(block[0], sizeof block[0]);
 	return(block[0]);
 }
 
@@ -1024,7 +1028,7 @@ row_merge_read_clustered_index(
 				goto func_exit;
 			}
 
-			UNIV_MEM_ALLOC(block[0], sizeof block[0]);
+			UNIV_MEM_INVALID(block[0], sizeof block[0]);
 			merge_buf[i] = row_merge_buf_empty(buf);
 		}
 
@@ -1218,7 +1222,7 @@ row_merge(
 			return(DB_CORRUPTION);
 		}
 
-		UNIV_MEM_ALLOC(block[0], sizeof block[0]);
+		UNIV_MEM_INVALID(block[0], sizeof block[0]);
 	}
 
 	/* Swap file descriptors for the next pass. */