[tarantool-patches] Re: [PATCH 3/4] vinyl: abort affected transactions when space is removed from cache

[Konstantin Osipov <kostja@tarantool.org>]

* Vladimir Davydov <vdavydov.dev@gmail.com> [19/03/24 00:10]:
> A DDL operation creates a new struct space container, moving unaffected
> indexes from the old container, then destroying it. The problem is there
> may be a DML request for this space, which was passed the old container
> in the argument list and then yielded on disk read. When it resumes, it
> may try to dereference the old space container, which may have already
> been destroyed. This will most certainly result in a crash.
> 
> To address this problem, we introduce a new space callback, invalidate,
> which is called for the old space on space_cache_replace(). In case of
> vinyl, this callback aborts all transactions involving the space. To
> prevent a DML request from dereferencing a destroyed space, we also make
> the iterator code check the current transaction state after each yield
> and return an error if it was aborted. This should make any DML request
> bail out early without dereferencing the space anymore.

This patch looks good to me. I don't share Georgy's concerns. I
would make the name of the callback more explicit, like
abort_transactions_in_engine, so that it clear what it is doing
now. In future, should we find more use for it, I would rename it.


-- 
Konstantin Osipov, Moscow, Russia, +7 903 626 22 32
http://tarantool.io - www.twitter.com/kostja_osipov