Horton

Re: Partial index creation always scans the entire table

Sergei Kornilov <sk@zsrv.org>

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From: Sergei Kornilov <sk@zsrv.org>
To: MingJu Wu <mingjuwu0505@gmail.com>, "pgsql-performance@lists.postgresql.org" <pgsql-performance@lists.postgresql.org>
Date: 2020-02-15T12:47:51Z
Lists: pgsql-performance 
Hello

> When creating partial indexes, can postgres utilize another index for figuring which rows should be included in the partial index, without performing a full table scan?

No.
create index always perform a seqscan on table. And two full table scan for create index concurrently.

regards, Sergei

Commits

  1. Doc: discourage use of partial indexes for poor-man's-partitioning.