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From: Tom Lane <[email protected]>
To: Robert Haas <[email protected]>
Cc: Jonathan S. Katz <[email protected]>
Cc: David Rowley <[email protected]>
Cc: Heikki Linnakangas <[email protected]>
Cc: Peter Geoghegan <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Cc: [email protected]
Subject: Re: On disable_cost
Date: Fri, 23 Aug 2024 13:42:53 -0400
Message-ID: <[email protected]> (raw)
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Robert Haas <[email protected]> writes:
> On Fri, Aug 23, 2024 at 1:26 PM Tom Lane <[email protected]> wrote:
>> It looks like amcostestimate could change the path's disabled_nodes
>> count, since that's set up before invoking amcostestimate.  I guess
>> it could be set to INT_MAX to have a comparable solution to before.

> It's probably better to add a more modest value, to avoid overflow.
> You could add a million or so and be far away from overflow while
> presumably still being more disabled than any other path.

But that'd only matter if the path survived its first add_path
tournament, which it shouldn't.  If it does then you're at risk
of the same run-time failure reported here.

(Having said that, you're likely right that "a million or so"
would be a safer choice, since it doesn't require the assumption
that the path fails instantly.)

			regards, tom lane






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