From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 6 Apr 2018 17:23:39 +0300 From: Vladimir Davydov Subject: Re: [PATCH v2 2/2] alter: zap space_vtab::commit_alter Message-ID: <20180406142339.3vzwcwv7z7ttdibu@esperanza> References: <20180406141001.GE18946@atlas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180406141001.GE18946@atlas> To: Konstantin Osipov Cc: tarantool-patches@freelists.org List-ID: On Fri, Apr 06, 2018 at 05:10:01PM +0300, Konstantin Osipov wrote: > * Vladimir Davydov [18/04/06 16:20]: > > > space_vtab::commit_alter is implemented only by memtx, which uses it > > to set bsize for a new space. However, it isn't necessary to use > > commit_alter for this - instead we can set bsize in prepare_alter and > > reset it in drop_primary_key, along with memtx_space::replace. Let's > > do it and zap space_vtab::commit_alter altogether, because the callback > > is confusing: judging by its name it should be called after WAL write, > > but it is called before. > > void > > DropIndex::alter(struct alter_space *alter) > > { > > - /* > > - * If it's not the primary key, nothing to do -- > > - * the dropped index didn't exist in the new space > > - * definition, so does not exist in the created space. > > - */ > > - if (space_index(alter->new_space, 0) != NULL) > > - return; > > - /* > > - * OK to drop the primary key. Inform the engine about it, > > - * since it may have to reset handler->replace function, > > - * so that: > > - * - DML returns proper errors rather than crashes the > > - * program > > - * - when a new primary key is finally added, the space > > - * can be put back online properly. > > - */ > > - space_drop_primary_key(alter->new_space); > > + if (old_index_def->iid == 0) > > + space_drop_primary_key(alter->new_space); > > } > > I keep wondering why you ditched a nice comment. > If you think it was bad, please write a better one. This comment is only pertinent to memtx so I just moved it to memtx_space_drop_primary_key. Regarding DropIndex::alter() - the code is pretty self-explaining there (call drop_primary_key if the primary key is dropped) and doesn't need any comments IMO. > > The patch is OK to push after putting back the previous or adding > a new good comment.