Re: [PATCH] vinyl: abort rw transactions before DDL

[Vladimir Davydov <vdavydov.dev@gmail.com>]

On Fri, Aug 24, 2018 at 12:10:57AM +0300, Konstantin Osipov wrote:
> * Vladimir Davydov <vdavydov.dev@gmail.com> [18/08/03 18:23]:
> > When building a new index or checking a space format, we propagate
> > changes done to the space during the procedure with the aid of an
> > on_replace trigger. The problem is there may be transactions with a
> > non-empty write set when we install the trigger. Changes done by
> > those transactions will not be seen by the trigger and so they won't
> > make it to the new index, resulting in an inconsistency between the
> > primary and secondary indexes. To fix this issue, let's abort all
> > rw transactions after setting the trigger. Note, transactions that
> > reached WAL can't be aborted so we wait for them to complete.
> 
> If I may nitpick:
> - we could have a list per lsm, not a global one in tx manager
> - abort only the transactions which are in the list of this lsm

This would be a little bit more difficult to implement, because the same
transaction can modify multiple LSM trees, but yeah, it makes sense.
I'll look into tihs.

> 
> This would both exclude read transactions and reduce the amount of
> aborted transactions a great deal.