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Re: ALTER TABLE SET ACCESS METHOD on partitioned tables

Jelte Fennema <postgres@jeltef.nl>

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From: Jelte Fennema-Nio <postgres@jeltef.nl>
To: Michael Paquier <michael@paquier.xyz>
Cc: Justin Pryzby <pryzby@telsasoft.com>, Peter Eisentraut <peter@eisentraut.org>, Soumyadeep Chakraborty <soumyadeep2007@gmail.com>, Zhihong Yu <zyu@yugabyte.com>, pgsql-hackers@postgresql.org, Ashwin Agrawal <ashwinstar@gmail.com>, vanjared@vmware.com
Date: 2024-03-01T04:43:25Z
Lists: pgsql-hackers 
On Fri, 1 Mar 2024 at 02:57, Michael Paquier <michael@paquier.xyz> wrote:
> When it comes to partitioned tables, there is a still a tricky case:
> what should we do when a user specifies a non-default value in the SET
> ACCESS METHOD clause and it matches default_table_access_method?
> Should the relam be 0 or should we force relam to be the OID of the
> given value given by the query?  Implementation-wise, forcing the
> value to 0 is simpler, but I can get why it could be confusing as
> well, because the state of the catalogs does not reflect what was
> provided in the query.  At the same time, the user has explicitly set
> the access method to be the same as the default, so perhaps 0 makes
> sense anyway in this case.

I think we should set the AM OID explicitly. Because an important
thing to consider is: What behaviour makes sense when later
default_table_access_method is changed?
I think if someone sets it explicitly on the partitioned table, they
would want the AM of the partitioned table to stay the same when
default_table_access_method is changed. Which requires storing the AM
OID afaict.

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Add information about access method for partitioned relations in \dP+

  2. Fix dumps of partitioned tables with table AMs

  3. Don't use the pg_am system catalog in new test

  4. ALTER TABLE: rework determination of access method ID

  5. Allow specifying an access method for partitioned tables

  6. Review wording on tablespaces w.r.t. partitioned tables

  7. Add support for DEFAULT in ALTER TABLE .. SET ACCESS METHOD

  8. Update comment of AlterTableCmd->name in parsenodes.h