branches/zip: btr_compress(): Do not modify the node pointer until the

records have successfully been copied.

btr/btr0btr.c

@@ -2247,27 +2247,6 @@ btr_compress(
 	/* Remove the page from the level list */
 	btr_level_list_remove(tree, page, mtr);
 
-	if (is_left) {
-		btr_node_ptr_delete(tree, page, mtr);
-	} else {
-		mem_heap_t*	heap		= NULL;
-		ulint		offsets_[REC_OFFS_NORMAL_SIZE];
-		*offsets_ = (sizeof offsets_) / sizeof *offsets_;
-		/* Replace the address of the old child node (= page) with the
-		address of the merge page to the right */
-
-		btr_node_ptr_set_child_page_no(node_ptr,
-				buf_block_get_page_zip(
-				buf_block_align(node_ptr)),
-				rec_get_offsets(node_ptr, cursor->index,
-				offsets_, ULINT_UNDEFINED, &heap),
-				right_page_no, mtr);
-		if (UNIV_LIKELY_NULL(heap)) {
-			mem_heap_free(heap);
-		}
-		btr_node_ptr_delete(tree, merge_page, mtr);
-	}
-
 	/* Move records to the merge page */
 	if (is_left) {
 		rec_t*	orig_pred = page_rec_get_prev(
@@ -2280,10 +2259,15 @@ btr_compress(
 			return(FALSE);
 		}
 
+		btr_node_ptr_delete(tree, page, mtr);
 		lock_update_merge_left(merge_page, orig_pred, page);
 	} else {
-		rec_t*	orig_succ = page_rec_get_next(
+		mem_heap_t*	heap		= NULL;
+		ulint		offsets_[REC_OFFS_NORMAL_SIZE];
+		rec_t*		orig_succ = page_rec_get_next(
 					page_get_infimum_rec(merge_page));
+		*offsets_ = (sizeof offsets_) / sizeof *offsets_;
+
 		if (UNIV_UNLIKELY(!page_copy_rec_list_end(
 				merge_page, buf_block_get_page_zip(
 					buf_block_align(merge_page)),
@@ -2292,6 +2276,20 @@ btr_compress(
 			return(FALSE);
 		}
 
+		/* Replace the address of the old child node (= page) with the
+		address of the merge page to the right */
+
+		btr_node_ptr_set_child_page_no(node_ptr,
+				buf_block_get_page_zip(
+				buf_block_align(node_ptr)),
+				rec_get_offsets(node_ptr, cursor->index,
+				offsets_, ULINT_UNDEFINED, &heap),
+				right_page_no, mtr);
+		if (UNIV_LIKELY_NULL(heap)) {
+			mem_heap_free(heap);
+		}
+		btr_node_ptr_delete(tree, merge_page, mtr);
+
 		lock_update_merge_right(orig_succ, page);
 	}