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From: Tom Lane <[email protected]>
To: Markus Demleitner <[email protected]>
Cc: [email protected]
Subject: Re: Index not used in certain nested views but not in others
Date: Tue, 13 May 2025 10:12:46 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <20250512141217.4dwnfxbaf53mhvi7@victor>
References: <20250430151647.7kootztymzznydn5@victor>
	<[email protected]>
	<[email protected]>
	<20250512141217.4dwnfxbaf53mhvi7@victor>

Markus Demleitner <[email protected]> writes:
> You see, when creating the "big", 30-tables view, I do cast all
> columns to common types in the view statement that actually make up
> the view.  The original SQL fragments look like this:

>   SELECT
>     CAST(ssa_dstype AS text) AS dataproduct_type,
>     CAST(NULL AS text) AS dataproduct_subtype,
>     CAST(2 AS smallint) AS calib_level,
>     ...

> and have a common source, so I'd believe by the time the things end
> up in the view, they should type-align even though their source
> tables do not.

Oh, well, that's your problem.  The source tables' column types
need to match.  Otherwise the UNIONs don't get flattened and you
don't get indexscans.

			regards, tom lane

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