Re: pg_dump and not MVCC-safe commands

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From: PetSerAl <[email protected]>
To: Tom Lane <[email protected]>
Cc: Guillaume Lelarge <[email protected]>
Cc: [email protected]
Subject: Re: pg_dump and not MVCC-safe commands
Date: Mon, 20 May 2024 18:49:46 +0300
Message-ID: <CAKygsHS2rKkzRFh-SygCjR-TGLhpbWxci4Ms5BxoJ9KJ5DXhxA@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
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	<[email protected]>

> However, it would be the very same
> database state that any other query would see at that time.
Other queries can use different techniques to prevent this. For
example, lock tables before snapshot, as recommended in documentation.
I understand, that pg_dump can not use that, as it need snapshot to
enumerate tables to lock.

> then you brought
> that on your own head by using TRUNCATE concurrently with other
> operations.
People, who admins database servers, are not always the same people,
who write application/queries. That means, if you know nothing about
application, you can not guarantee, if live database backup would be
consistent. Basically, you need application cooperation to make
consistent live database backup.

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