From: Nikolay Shaplov <n.shaplov@postgrespro.ru>
To: Alvaro Herrera <alvherre@2ndquadrant.com>, pgsql-hackers@postgresql.org
Subject: Re: [PROPOSAL] Move all am-related reloption code into
 src/backend/access/[am-name] and get rid of relopt_kind
Date: Fri, 27 May 2016 22:24:50 +0300
Message-ID: <1972481.VQZ2401KyW@home>
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References: <20160527190558.GA703687@alvherre.pgsql>
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=D0=92 =D0=BF=D0=B8=D1=81=D1=8C=D0=BC=D0=B5 =D0=BE=D1=82 27 =D0=BC=D0=B0=D1=
=8F 2016 15:05:58 =D0=92=D1=8B =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB=
=D0=B8:
> 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. That was not
> > necessary before, because all reloptions at that existed at that time c=
an
> > be changed on fly. But now for bloom index it is unacceptable, because
> > for changing bloom's reloptions for existing index will lead to index
> > malfunction.
>=20
> 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.
>=20
> I think Bloom should do likewise.

I do not think that it is the best behavior. Because if we came to this=20
situation, the current value of pages_per_range that index actually using i=
s=20
not available for user, because he is not able to look into meta page.

In this case it would be better either forbid changing the options, so it=20
would be consistent, or force index rebuild, then it would be consistent to=
o.=20
I would vote for first behavior as this is less work to do for me, and can =
be=20
changed later, if it is really needed for some case.

PS sorry I did not add mail list to the CC, so I send it second time...


--=20
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