Re: speedup COPY TO for partitioned table.

On Fri, Mar 21, 2025 at 6:13 PM vignesh C <vignesh21(at)gmail(dot)com> wrote:
>
> I find an issue with the patch:
>
> -- Setup
> CREATE SERVER myserver FOREIGN DATA WRAPPER postgres_fdw OPTIONS
> (dbname 'testdb', port '5432');
> CREATE TABLE t1(id int) PARTITION BY RANGE(id);
> CREATE TABLE part1 PARTITION OF t1 FOR VALUES FROM (0) TO (5);
> CREATE TABLE part2 PARTITION OF t1 FOR VALUES FROM (5) TO (15)
> PARTITION BY RANGE(id);
> CREATE FOREIGN TABLE part2_1 PARTITION OF part2 FOR VALUES FROM (10)
> TO (15) SERVER myserver;
>
> -- Create table in testdb
> create table part2_1(id int);
>
> -- Copy partitioned table data
> postgres=# copy t1 to stdout(header);
> server closed the connection unexpectedly
> This probably means the server terminated abnormally
> before or while processing the request.
>

I manually tested:
sequence, temp table, materialized view, index, view,
composite types, partitioned indexes.
all these above can not attach to partitioned tables.

We should care about the unlogged table, foreign table attached to the
partition.
an unlogged table should work just fine.
we should error out foreign tables.

so:
copy t1 to stdout(header);
ERROR: cannot copy from foreign table "t1"
DETAIL: partition "t1" is a foreign table
HINT: Try the COPY (SELECT ...) TO variant.