Feedback-ID: i0fe9450f:Fastmail
Date: Tue, 28 Mar 2023 14:56:28 +0900
From: Michael Paquier <michael@paquier.xyz>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Soumyadeep Chakraborty <soumyadeep2007@gmail.com>,
	Zhihong Yu <zyu@yugabyte.com>, pgsql-hackers@postgresql.org,
	Ashwin Agrawal <ashwinstar@gmail.com>, vanjared@vmware.com
Subject: Re: ALTER TABLE SET ACCESS METHOD on partitioned tables
Message-ID: <ZCKBjKVCgKxaU3+U@paquier.xyz>
References: <ZCIxFkgOGv64nYE7@paquier.xyz>
 <ZCJuW3GOfE/0eBjh@telsasoft.com>
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On Mon, Mar 27, 2023 at 11:34:35PM -0500, Justin Pryzby wrote:
> I realized that one difference with tablespaces is that, as written,
> partitioned tables will *always* have an AM specified,  and partitions
> will never use default_table_access_method.  Is that what's intended ?
>
> Or do we need logic similar tablespaces, such that the relam of a
> partitioned table is set only if it differs from default_table_am ?

Hmm.  This is a good point.  It is true that the patch feels
incomplete on this side.  I don't see why we could not be flexible,
and allow a value of 0 in a partitioned table's relam to mean that we
would pick up the database default in this case when a partition is
is created on it.  This would have the advantage to be consistent with
older versions where we fallback on the default.  We cannot be
completely consistent with the reltablespace of the leaf partitions
unfortunately, as relam should always be set if a relation has
storage.  And allowing a value of 0 means that there are likely other
tricky cases with dumps?

Another thing: would it make sense to allow an empty string in
default_table_access_method so as we'd always fallback to a database
default?
--
Michael

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