Re: pgsql_fdw, FDW for PostgreSQL server

Shigeru Hanada wrote:
[pgsql_fdw_v12.patch]

I know this is not the latest version, but I played around with it and
tickled a bug.
It seems to have a problem with rolled back subtransactions.

test=> \d+ remote
Foreign table "laurenz.remote"
Column | Type | Modifiers | FDW Options | Storage | Description
--------+---------+-----------+-------------+----------+-------------
id | integer | not null | | plain |
val | text | not null | | extended |
Server: loopback
FDW Options: (nspname 'laurenz', relname 'local')
Has OIDs: no
test=> BEGIN;
test=> DECLARE x CURSOR FOR SELECT * FROM remote;
DEBUG: Remote SQL: SELECT id, val FROM laurenz.local
DEBUG: relid=16423 fetch_count=10000
DEBUG: starting remote transaction with "START TRANSACTION ISOLATION
LEVEL REPEATABLE READ"
test=> FETCH x;
id | val
----+-----
1 | one
(1 row)
test=> SAVEPOINT z;
test=> ERROR OUT;
ERROR: syntax error at or near "ERROR"
LINE 1: ERROR OUT;
test=> ROLLBACK TO SAVEPOINT z;
test=> FETCH x;
id | val
----+-----
2 | two
(1 row)
test=> COMMIT;
ERROR: could not close cursor
DETAIL: no connection to the server

HINT: CLOSE pgsql_fdw_cursor_0

The error message reported is not consistent, at one attempt the backend
crashed.

Yours,
Laurenz Albe