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From: David G. Johnston <[email protected]>
To: Marcelo Fernandes <[email protected]>
Cc: [email protected] <[email protected]>
Subject: Re: Best way to check if a table is empty
Date: Sun, 23 Mar 2025 21:15:32 -0700
Message-ID: <CAKFQuwbXZ+9tY=graDAWfFaxeOOpdOoQ+JtjmaqWCWfZc-PF4g@mail.gmail.com> (raw)
In-Reply-To: <CAKFQuwY_N9QeJZJ3sgYC7Ui0nohZVX5NCzELanXKmpiVgxZbag@mail.gmail.com>
References: <CAM2F1VMbOEubpXk44B5KaWKX0OSVrA8-9xqidhJMNtDprhTSTg@mail.gmail.com>
	<CAKFQuwY_N9QeJZJ3sgYC7Ui0nohZVX5NCzELanXKmpiVgxZbag@mail.gmail.com>

On Sunday, March 23, 2025, David G. Johnston <[email protected]>
wrote:

>
> Maybe IOS helps though I do wonder whether a sequential scan skips over
> known all-dead pages making that relative benefit go away.
>

Well, no, since it tracks known visible, not known non-visible, though for
something like a fast exists test with no where clause if the VM had any 1
bits the answer to the exists would be yes.  No idea if we take that
shortcut.

David J.


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