Horton

Re: Parallel Seq Scan vs kernel read ahead

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Ranier Vilela <ranier.vf@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2020-05-21T21:59:58Z
Lists: pgsql-hackers 
On Thu, 21 May 2020 at 17:06, David Rowley <dgrowleyml@gmail.com> wrote:
> For the patch. I know you just put it together quickly, but I don't
> think you can do that ramp up the way you have. It looks like there's
> a risk of torn reads and torn writes and I'm unsure how much that
> could affect the test results here.

Oops. On closer inspection, I see that memory is per worker, not
global to the scan.

Commits

  1. Allocate consecutive blocks during parallel seqscans