Re: BUG #17211: Partitioned index partition does not inherit table partition tablespace

On Fri, Oct 1, 2021, at 3:07 PM, PG Bug reporting form wrote:
> Suppose we have 2 tablespaces:
> pg_default (which is slow)
> fast
>
> We also have a partitioned table:
> create table a (id serial not null, b int not null primary key, c int not
> null, d int) partition by hash (b);
>
> and 2 partitions:
> create table a_1 partition of a for values with (modulus 2, remainder 0);
> create table a_2 partition of a for values with (modulus 2, remainder 1)
> tablespace fast;
>
> This successfully allocates table a_2 pages within the 'fast' tablespace;
> but this fails to allocate a_2_pkey primary key index there too and the
> result is the index is allocated on tablespace oid(0) which means pg_default
> I guess, at least the corresponding relfilenode is allocated within the
> pg_default tablespace.
That's how it was designed. TABLESPACE clause at the end of CREATE TABLE set
the tablespace only for the table. The index is stored based on the
default_tablespace [1] value.

Since there is no way to specify USING INDEX TABLESPACE for partitions, you
should set default_tablespace to achieve what you want.

CREATE TABLE a (
id serial NOT NULL,
b int NOT NULL PRIMARY KEY,
c int NOT NULL,
d int
) PARTITION BY hash (b);

CREATE TABLE a_1 PARTITION OF a
FOR VALUES WITH (MODULUS 3, REMAINDER 0);

SET default_tablespace TO 'fast';

-- the TABLESPACE clause is not required
-- table -> fast ; index -> fast
CREATE TABLE a_2 PARTITION OF a
FOR VALUES WITH (MODULUS 3, REMAINDER 1) TABLESPACE fast;

-- table -> tablespace slow ; index -> tablespace fast
CREATE TABLE a_3 PARTITION OF a
FOR VALUES WITH (MODULUS 3, REMAINDER 2) TABLESPACE slow;

RESET default_tablespace;

[1] https://www.postgresql.org/docs/14/runtime-config-client.html#RUNTIME-CONFIG-CLIENT-STATEMENT

--
Euler Taveira
EDB https://www.enterprisedb.com/