Horton

Re: [UNVERIFIED SENDER] Re: NOT IN subquery optimization

Zheng (Zane) Li <zhelli@amazon.com>

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From: "Li, Zheng" <zhelli@amazon.com>
To: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2019-06-14T21:41:06Z
Lists: pgsql-hackers

Attachments

Rebased patch is attached.

Comments are welcome.

-----------
Zheng Li
AWS, Amazon Aurora PostgreSQL
 

On 6/14/19, 5:39 PM, "zhengli" <zhelli@amazon.com> wrote:

    In our patch, we only proceed with the ANTI JOIN transformation if
    subplan_is_hashable(subplan) is
    false, it requires the subquery to be planned at this point.
    
    To avoid planning the subquery again later on, I want to keep a pointer of
    the subplan in SubLink so that we can directly reuse the subplan when
    needed. However, this change breaks initdb for some reason and I'm trying to
    figure it out.
    
    I'll send the rebased patch in the following email since it's been a while.
    
    
    
    --
    Sent from: http://www.postgresql-archive.org/PostgreSQL-hackers-f1928748.html

Commits

  1. Check we don't misoptimize a NOT IN where the subquery returns no rows.