On 2015-07-24 00:39, Tom Lane wrote:
I wrote:
OK, so "InitSampleScan" for a function called at ExecInitSampleScan time
(which we might as well make optional), and then we'll use BeginSampleScan
for the function that gets the parameters. The restart/ReScan function
goes away since BeginSampleScan will take its place.
Here's a WIP patch implementing things this way. I've also taken the time
to do a complete code review, and fixed quite a large number of things,
some cosmetic and some not so much. I have not yet touched the tsm
contrib modules (so they won't even compile...), but I'm reasonably happy
with the state of the core code now.
Eh, I was just writing email with my rewrite :)
I'll do review of this instead then.
The only major difference that I see so far and I'd like you to
incorporate that into your patch is that I renamed the SampleScanCost to
SampleScanGetRelSize because that reflects much better the use of it, it
isn't really used for costing, but for getting the pages and tuples of
the baserel.
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Petr Jelinek http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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