Re: Parallel Seq Scan vs kernel read ahead

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Thomas Munro <thomas(dot)munro(at)gmail(dot)com>
Cc: David Rowley <dgrowleyml(at)gmail(dot)com>, Ranier Vilela <ranier(dot)vf(at)gmail(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Parallel Seq Scan vs kernel read ahead
Date: 2020-05-22 18:31:22
Message-ID: CA+TgmoZmqM2dji2+vhLZaRpruHs3Ojc0wTFa3Wj_Sm91-fw6=g@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On Thu, May 21, 2020 at 6:28 PM Thomas Munro <thomas(dot)munro(at)gmail(dot)com> wrote:
> Right, I think it's safe. I think you were probably right that
> ramp-up isn't actually useful though, it's only the end of the scan
> that requires special treatment so we don't get unfair allocation as
> the work runs out, due to course grain.

The ramp-up seems like it might be useful if the query involves a LIMIT.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Tom Lane 2020-05-22 19:04:10 Re: Policy on cross-posting to multiple lists
Previous Message Robert Haas 2020-05-22 18:30:20 Re: Parallel Seq Scan vs kernel read ahead