From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Vladimir Davydov Subject: [PATCH 05/12] alter: allocate triggers before the point of no return Date: Sat, 7 Apr 2018 16:38:02 +0300 Message-Id: <55a4b2ee61c194074a98f03c5f42306662a3d9e9.1523105106.git.vdavydov.dev@gmail.com> In-Reply-To: References: In-Reply-To: References: To: kostja@tarantool.org Cc: tarantool-patches@freelists.org List-ID: Trigger allocation, as any other memory allocation, is allowed to fail. If this happens in alter_space_do, the space will be left in an inconsistent state. Let's move trigger allocation to the beginning of alter_space_do and add a comment denoting the point of no return. --- src/box/alter.cc | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/src/box/alter.cc b/src/box/alter.cc index 36310f1c..9d0c4c23 100644 --- a/src/box/alter.cc +++ b/src/box/alter.cc @@ -803,6 +803,11 @@ alter_space_rollback(struct trigger *trigger, void * /* event */) static void alter_space_do(struct txn *txn, struct alter_space *alter) { + /* Prepare triggers while we may fail. */ + struct trigger *on_commit, *on_rollback; + on_commit = txn_alter_trigger_new(alter_space_commit, alter); + on_rollback = txn_alter_trigger_new(alter_space_rollback, alter); + /* Create a definition of the new space. */ space_dump_def(alter->old_space, &alter->key_list); class AlterSpaceOp *op; @@ -853,6 +858,11 @@ alter_space_do(struct txn *txn, struct alter_space *alter) throw; } + /* + * This function must not throw exceptions or yield after + * this point. + */ + /* Rebuild index maps once for all indexes. */ space_fill_index_map(alter->old_space); space_fill_index_map(alter->new_space); @@ -873,11 +883,7 @@ alter_space_do(struct txn *txn, struct alter_space *alter) * finish or rollback the DDL depending on the results of * writing to WAL. */ - struct trigger *on_commit = - txn_alter_trigger_new(alter_space_commit, alter); txn_on_commit(txn, on_commit); - struct trigger *on_rollback = - txn_alter_trigger_new(alter_space_rollback, alter); txn_on_rollback(txn, on_rollback); } -- 2.11.0