[Tarantool-patches] [PATCH v2] vinyl: restart read iterator in case of rolled back WAL

[Aleksandr Lyapunov]

>>> The read iterator was rewritten several times and still have at least
>>> several bugs. I think we should admit that we cannot support such a
>>> complicated solution. How about some stupid solution: if ANY change
>>> has been happened during yield - restart advancing?
> Does this statement have technical merit? Is it supported by
> tests? I'd gladly support the change if it was grounded in reason -
> evaluation of the performance impact, for example, could serve as
> a confirmation that a simple solution would be just fine.
>
> Without it, I'd it's a regress, a signature of helplessness,
> lack of courage to make things right.
Two reasons:
1. since we have to read from disk it's not a big deal to scan memory again.
2. a dozen of lines of code is removed - the cost of support is lowered 
a bit.