Re: Index only scans for expressional indices when querying for the expression

From: "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com>
To: Danny Shemesh <dany74q(at)gmail(dot)com>
Cc: "pgsql-general(at)lists(dot)postgresql(dot)org" <pgsql-general(at)lists(dot)postgresql(dot)org>
Subject: Re: Index only scans for expressional indices when querying for the expression
Date: 2022-08-04 12:28:07
Message-ID: CAKFQuwZTD0NydFg8Ra4kUuU2WDxY53FCx9Zh6_OwVjdCLThp8w@mail.gmail.com
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On Thursday, August 4, 2022, Danny Shemesh <dany74q(at)gmail(dot)com> wrote:
>
> I believe the expressional index in itself could've been considered as
> covering, when querying for the expression explicitly.
>

This belief is wrong. When storing f(x) there is no way to recover the
value of x.

David J.

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