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help / color / mirror / Atom feedFrom: Michael Paquier <[email protected]>
To: Dilip Kumar <[email protected]>
Cc: Nathan Bossart <[email protected]>
Cc: Ryo Matsumura (Fujitsu) <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: DDL result is lost by CREATE DATABASE with WAL_LOG strategy
Date: Thu, 16 Feb 2023 14:26:55 +0900
Message-ID: <Y+2+n4FuE6K5/[email protected]> (raw)
In-Reply-To: <CAFiTN-tEAaq6csi_6TB8sz=5ZV=XjhneUB0x5icfK8b3TLn+Xw@mail.gmail.com>
References: <TYCPR01MB6868677E499C9AD5123084B5E8A39@TYCPR01MB6868.jpnprd01.prod.outlook.com>
<20230216000659.GA1932550@nathanxps13>
<CAFiTN-tEAaq6csi_6TB8sz=5ZV=XjhneUB0x5icfK8b3TLn+Xw@mail.gmail.com>
On Thu, Feb 16, 2023 at 10:24:13AM +0530, Dilip Kumar wrote:
> Yes, there is no reason to pass this as false, seems like this is
> passed false by mistake. And your patch fixes the issue.
So, if I am understanding this stuff right, this issue can create data
corruption once a DDL updates any pages of pg_class stored in a
template database that gets copied by this routine. In this case, the
patch sent makes sure that any page copied will get written once a
checkpoint kicks in. Shouldn't we have at least a regression test for
such a scenario? The issue can happen when updating a template
database after creating a database from it, which is less worrying
than the initial impression I got, still I'd like to think that we
should have some coverage as of the special logic this code path
relies on for pg_class when reading its buffers.
I have not given much attention to this area, but I am a bit
suspicious that enforcing the default as WAL_LOG was a good idea for
15~, TBH. We are usually much more conservative when it comes to
such choices, switching to the new behavior after a few years would
have been wiser..
--
Michael
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To: [email protected]
Cc: [email protected], [email protected], [email protected], [email protected], [email protected]
Subject: Re: DDL result is lost by CREATE DATABASE with WAL_LOG strategy
In-Reply-To: <Y+2+n4FuE6K5/[email protected]>
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