Re: ALTER TABLE SET ACCESS METHOD on partitioned tables

> @@ -947,20 +947,22 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
> * a type of relation that needs one, use the default.
> */
> if (stmt->accessMethod != NULL)
> + accessMethodId = get_table_am_oid(stmt->accessMethod, false);
> + else if (RELKIND_HAS_TABLE_AM(relkind) || relkind == RELKIND_PARTITIONED_TABLE)
> {
> - accessMethod = stmt->accessMethod;
> -
> - if (partitioned)
> - ereport(ERROR,
> - (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> - errmsg("specifying a table access method is not supported on a partitioned table")));
> + if (stmt->partbound)
> + {
> + /*
> + * For partitions, if no access method is specified, use the AM of
> + * the parent table.
> + */
> + Assert(list_length(inheritOids) == 1);
> + accessMethodId = get_rel_relam(linitial_oid(inheritOids));
> + Assert(OidIsValid(accessMethodId));
> + }
> + else
> + accessMethodId = get_table_am_oid(default_table_access_method, false);
> }

I think this works similarly but not identically to tablespace defaults,
and the difference could be confusing. You seem to have made it so that
the partitioned table _always_ have a table AM, so the partitions can
always inherit from it. I think it would be more sensible to _allow_
partitioned tables to have one, but not mandatory; if they don't have
it, then a partition created from it would use default_table_access_method.

--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
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