[tarantool-patches] [PATCH 4/4] txn: undo commit/rollback triggers when reverting to savepoint

[Vladimir Davydov]

On Fri, Jul 19, 2019 at 09:36:08PM +0200, Vladislav Shpilevoy wrote:
> 
> 
> On 19/07/2019 20:08, Vladimir Davydov wrote:
> > When reverting to a savepoint inside a DDL transaction, apart from
> > undoing changes done by the DDL statements to the system spaces, we also
> > have to
> > 
> >  - Run rollback triggers installed after the savepoint was set, because
> >    otherwise changes done to the schema by DDL won't be undone.
> >  - Remove commit triggers installed after the savepoint, because they
> >    are not relevant anymore, apparently.
> > 
> > To achieve that, let's remember not only the last transaction statement
> > at the time when a savepoint is created, but also the state of commit
> > and rollback triggers. Since in contrast to txn statements, commit and
> > rollback triggers can actually be deleted from the list, we create dummy
> > triggers per each savepoint and use them as markers in the trigger
> > lists. We don't however create dummy triggers if no commit/rollback
> > triggers is installed, because in that case we would simply need to
> > clear the trigger lists.
> > 
> > While we are at it, let's also make sure that a rollback trigger doesn't
> > an already freed tuple. To do that, we release statement tuples after
> 
> Nit: 'rollback trigger doesn't an already freed'. Perhaps I am wrong,
> but shouldn't be here a verb after 'doesn't'?

Yep, I missed word 'access'. Fixed. Thanks.