Re: On disable_cost - Mailing list pgsql-hackers

From Tom Lane
Subject Re: On disable_cost
Date
Msg-id 2269318.1724434973@sss.pgh.pa.us
Whole thread Raw
In response to Re: On disable_cost  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Fri, Aug 23, 2024 at 1:26 PM Tom Lane <tgl@sss.pgh.pa.us> 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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