Re: Regarding identifying a foreign scan

Atri Sharma <atri(dot)jiit(at)gmail(dot)com> writes:
> The issue I am trying to resolve is that if two scans are taking place
> on the same backend(due to the same query),then,the server is
> crashing.

That sounds like an FDW bug ... which FDW are we talking about?

> I think it is because I am not saving the state of the scan,so,if
> multiple scans a re running on the same backend,then,it is causing the
> crash.

The FDW should certainly not assume that only one scan can happen at a
time. I would not think this would be a problem as long as you're using
reasonable coding techniques, like keeping scan-local state in
scan-local storage and not globally.

> Any hints on how I can detect this condition please?

If you are imagining that you'd do something differently depending on
whether the current query contains multiple ForeignScan nodes for your
FDW, that's still doomed to lose, because of nested queries. You really
need to manage storage in a way that doesn't make assumptions of this
sort.

regards, tom lane