Re: Let's remove DSM_INPL_NONE. - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Let's remove DSM_INPL_NONE.
Date
Msg-id 32164.1519761235@sss.pgh.pa.us
Whole thread Raw
In response to Re: Let's remove DSM_INPL_NONE.  (Andres Freund <andres@anarazel.de>)
Responses Re: Let's remove DSM_INPL_NONE.
List pgsql-hackers
Andres Freund <andres@anarazel.de> writes:
> On 2018-02-27 14:41:47 -0500, Tom Lane wrote:
>> What I didn't understand about it was what kind of testing this'd make
>> harder.  If we desupport dynamic_shared_memory_type=none, there aren't
>> any code paths that need to cope with the case, and we should just
>> remove any code that thereby becomes unreachable.

> What I'm concerned about isn't so much testing paths specific to
> dynamic_shared_memory_type=none, but paths where we currently need
> fallbacks for the case we couldn't actually allocate dynamic shared
> memory. Which I think we at least somewhat gracefully need to deal with.

Ah.  That's a fair point, but I do not think
dynamic_shared_memory_type=none is a good substitute for having a way to
provoke allocation failures.  That doesn't let you test recovery from
situations where your first allocation works and second one fails, for
example; and cleanup from that sort of case is likely to be more
complicated than the trivial case.

            regards, tom lane


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