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help / color / mirror / Atom feedFrom: Michael Paquier <[email protected]>
To: Tom Lane <[email protected]>
Cc: Bruce Momjian <[email protected]>
Cc: Robert Haas <[email protected]>
Cc: Peter Geoghegan <[email protected]>
Cc: Matthias van de Meent <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: Preventing indirection for IndexPageGetOpaque for known-size page special areas
Date: Tue, 29 Nov 2022 09:22:22 +0900
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
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<[email protected]>
<[email protected]>
On Mon, Nov 28, 2022 at 05:31:50PM -0500, Tom Lane wrote:
> After looking through this thread, I side with Robert: we should reject
> the remainder of this patch. It gives up page layout flexibility that
> we might want back someday. Moreover, I didn't see any hard evidence
> offered that there's any actual performance gain, let alone such a
> compelling gain that we should give up that flexibility for it.
As far as I understand, we are talking about this one:
https://www.postgresql.org/message-id/[email protected]...
After a few months looking at it again, I cannot get much excited
about switching these routines from a logic where we look at the page
header to something where we'd rely on the opaque structure size.
I am wondering if it would be worth adding an AssertMacro() like in
this one, though:
https://www.postgresql.org/message-id/[email protected]
This still uses PageGetSpecialPointer() to retrieve the pointer area
from the page header, but it also checks that we have a match with the
structure expected by the index AM.
--
Michael
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To: [email protected]
Cc: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
Subject: Re: Preventing indirection for IndexPageGetOpaque for known-size page special areas
In-Reply-To: <[email protected]>
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