Re: [PROPOSAL] Move all am-related reloption code into src/backend/access/[am-name] and get rid of relopt_kind

Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> writes:
> Nikolay Shaplov wrote:
>> Story start from the point that I found out that a.m. can not forbid changing
>> some of it's reloptions with ALTER INDEX command.

> Hmm, this sounds like a bug to me. In BRIN, if you change the
> pages_per_range option for an existing index, the current index
> continues to work because the value used during the last index build is
> stored in the metapage. Only when you reindex after changing the option
> the new value takes effect.

> I think Bloom should do likewise.

AFAICT, Bloom *does* do that. The reloptions are only consulted directly
while initializing the metapage.

I think Nikolay's complaint is essentially that there should be a way
for an AM to forbid ALTER INDEX if it's not going to support on-the-fly
changes of a given reloption. That might be a helpful usability
improvement, but it's only a usability improvement not a bug fix.

regards, tom lane