branches/zip: Fix a bug that was triggered during purge.

btr_compress(): Defer any tree modifications until the records
have successfully been copied.

row_purge_remove_sec_if_poss_low(): Simplify the setting of
the return status.

btr/btr0btr.c

@@ -2259,11 +2259,6 @@ btr_compress(
 		}
 	}
 
-	btr_search_drop_page_hash_index(page);
-
-	/* Remove the page from the level list */
-	btr_level_list_remove(tree, page, mtr);
-
 	/* Move records to the merge page */
 	if (is_left) {
 		rec_t*	orig_pred = page_rec_get_prev(
@@ -2276,6 +2271,11 @@ btr_compress(
 			return(FALSE);
 		}
 
+		btr_search_drop_page_hash_index(page);
+
+		/* Remove the page from the level list */
+		btr_level_list_remove(tree, page, mtr);
+
 		btr_node_ptr_delete(tree, page, mtr);
 		lock_update_merge_left(merge_page, orig_pred, page);
 	} else {
@@ -2293,6 +2293,11 @@ btr_compress(
 			return(FALSE);
 		}
 
+		btr_search_drop_page_hash_index(page);
+
+		/* Remove the page from the level list */
+		btr_level_list_remove(tree, page, mtr);
+
 		/* Replace the address of the old child node (= page) with the
 		address of the merge page to the right */
 

row/row0purge.c

@@ -265,13 +265,8 @@ row_purge_remove_sec_if_poss_low(
 			ut_ad(mode == BTR_MODIFY_TREE);
 			btr_cur_pessimistic_delete(&err, FALSE, btr_cur,
 							FALSE, &mtr);
-			if (err == DB_SUCCESS) {
-				success = TRUE;
-			} else if (err == DB_OUT_OF_FILE_SPACE) {
-				success = FALSE;
-			} else {
-				ut_error;
-			}
+			success = err == DB_SUCCESS;
+			ut_a(success || err == DB_OUT_OF_FILE_SPACE);
 		}
 	}