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

Vladislav Shpilevoy v.shpilevoy at tarantool.org
Fri Jul 19 22:36:08 MSK 2019



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'?

> running rollback triggers, not before as we used to.
> 
> Closes #4364
> Closes #4365
> ---



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