Re: LIMIT confuses the planner

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Tom Lane wrote:
Robert Haas <robertmhaas@xxxxxxxxx> writes:
If you left seq_page_cost (which isn't mentioned here) at the default
value but reduced random_page_cost to 0.1, then you have
random_page_cost < seq_page_cost.  That's probably Bad.

... well, it's certainly going to push the planner to believe indexscans
are cheaper than sorts no matter what.

The previously noted rowcount estimation problem might be a bigger issue
in this particular case, but I agree this is a Bad Idea.

So I've set it wrong, I guess. :-)

Now I put it to:

seq_page_cost = 1
random_page_cost = 2

Regards,
--
Kouber Saparev
http://kouber.saparev.com

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