Hi!
Thanks for your comments.
When performing space: truncate(), we are executing
simple upsert. How can we distinguish it from any other upsert to use reserved extents tech? пятница, 31 января 2020г., 11:21 +03:00 от Konstantin Osipov  kostja.osipov@gmail.com :

>* Ilya Kosarev < i.kosarev@tarantool.org> [20/01/20 21:18]:
> Trying to perform space:truncate() and space:delete() while reaching
> memtx_memory limit we could experience slab allocator failure. This
> behavior seems to be quite surprising for users. Now we are allowing
> to overuse memtx quota if needed for truncation or deletion, using flag
> in struct quota. After performing truncation or deletion we reset the
> flag so that quota can be overused any more.
>
>This is duplicating the tech already existing with reserved
>extents.
>
>Why not use the reserved extents instead? Why do you need to turn
>quota completely on/off?
>
>
>-- 
>Konstantin Osipov, Moscow, Russia