Re: ALTER TABLE SET ACCESS METHOD on partitioned tables

Zhihong Yu <zyu@yugabyte.com>

From: Zhihong Yu <zyu@yugabyte.com>

To: Soumyadeep Chakraborty <soumyadeep2007@gmail.com>

Cc: Justin Pryzby <pryzby@telsasoft.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Michael Paquier <michael@paquier.xyz>, Ashwin Agrawal <ashwinstar@gmail.com>, vanjared@vmware.com

Date: 2022-05-19T01:31:46Z

Lists: pgsql-hackers

On Wed, May 18, 2022 at 5:49 PM Soumyadeep Chakraborty <
soumyadeep2007@gmail.com> wrote:

>
> On Wed, May 18, 2022 at 4:14 PM Justin Pryzby <pryzby@telsasoft.com>
> wrote:
>
> > I didn't look closely yet, but this comment is wrong:
> >
> > + * Since these have no storage the tablespace can be updated with a
> simple
>
>
> > + * metadata only operation to update the tablespace.
>
>
>
>
> Good catch. Fixed.
>
> > It'd be convenient if AMs worked the same way (and a bit odd that they
> don't).
> > Note that in v15, pg_dump/restore now allow --no-table-am, an exact
> parallel to
> > --no-tablespace.
>
> I agree that ATSET AM should behave in a similar fashion to ATSET
> tablespaces.
> However, the way that ATSET tablespace currently behaves is not consistent
> with
> the ONLY clause.
>
> On a given partition root:
> ALTER TABLE ONLY am_partitioned SET TABLESPACE ts;
> has the same effect as:
> ALTER TABLE am_partitioned SET TABLESPACE ts;
>
> We are missing out on the feature to set the AM/tablespace throughout the
> partition hierarchy, with one command.
>
> Regards,
> Soumyadeep (VMware)
>
> Hi,

+       accessMethodId = ((Form_pg_class) GETSTRUCT(tup))->relam;

-   /* look up the access method, verify it is for a table */
-   if (accessMethod != NULL)
-       accessMethodId = get_table_am_oid(accessMethod, false);
+       if (!HeapTupleIsValid(tup))
+           elog(ERROR, "cache lookup failed for relation %u", relid);

The validity check of tup should be done before fetching the value of
relam field.

Cheers

Commits

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

Add information about access method for partitioned relations in \dP+
- 978f38c771fb 18.0 landed
Fix dumps of partitioned tables with table AMs
- f46bee346c3b 17.0 landed
Don't use the pg_am system catalog in new test
- 13b3b62746ec 17.0 landed
ALTER TABLE: rework determination of access method ID
- e2395cdbe83a 17.0 landed
Allow specifying an access method for partitioned tables
- 374c7a229042 17.0 landed
Review wording on tablespaces w.r.t. partitioned tables
- ea299d782511 15.7 landed
- e6c4e01bf440 16.3 landed
- a0390f6ca6c7 17.0 landed
- 58efabdc0ce9 12.19 landed
- 520e7afa5732 13.15 landed
- 33bfbef1d60f 14.12 landed
Add support for DEFAULT in ALTER TABLE .. SET ACCESS METHOD
- d61a6cad6418 17.0 landed
Update comment of AlterTableCmd->name in parsenodes.h
- 4f8c1e7aaf11 17.0 landed