Subject: Re: About postgres pg_upgrade

From: Daniel Gustafsson <[email-masked]>
Date: Fri, 5 Apr 2024 09:41:05 +0200

> On 5 Apr 2024, at 06:47, Rama Krishnan <[email-masked]> wrote:

> Could you please explain me how does pg_upgrade works one of my friends it works based on pg_restore I am bit confused

The documentation does a fairly good job explaining how it works, and there are
multiple blogposts and presentations on the subject to be found.

	https://www.postgresql.org/docs/devel/pgupgrade.html

To summarize in a few words, pg_upgrade does a dump/restore of the schema from
the old cluster into the new, but copies the table data.  Your friend is thus
isn't wrong, it does use pg_restore but only for the schema, not the data.

--
Daniel Gustafsson

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From: Bruce Momjian <[email-masked]>
Date: Sat, 6 Apr 2024 13:41:02 -0400

> isn't wrong, it does use pg_restore but only for the schema, not the data.

This presentation shows how it works internally:

	https://momjian.us/main/writings/pgsql/pg_upgrade.pdf

-- 
  Bruce Momjian  <[email-masked]>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.