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Why analyze reports 30000 pages and rows scanned. Why not just rows? - Mailing list pgsql-general

From David Mullineux
Subject Why analyze reports 30000 pages and rows scanned. Why not just rows?
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Msg-id CAGsyd8UWZr3DiAxTgZqnsJU_LipoL9fhyForcC=B8tzxwEyPLw@mail.gmail.com
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Responses Re: Why analyze reports 30000 pages and rows scanned. Why not just rows?
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According to docs, analyze ,by default, will try to sample 30000 rows from a table.
(I've read analyze.c note about Haas and Stokes IBM Research ).

But my question is, why does 'analyze verbose' report that it has scanned '30000 of NNNN pages, containing NNNN live rows and 0 dead rows; 30000 rows in sample,....'

As most tables would store more than 1 row per page, I expected that 30000 rows would require a lot fewer than 30000 pages to be scanned.  Why is it saying it's scanned 30000 pages instead of only 30000 rows ?


Confused. thanks.

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