postgres/contrib/postgres_fdw
Etsuro Fujita 5c571a34d0 postgres_fdw: Avoid "cursor can only scan forward" error.
Commit d844cd75a disallowed rewind in a non-scrollable cursor to resolve
anomalies arising from such a cursor operation.  However, this failed to
take into account the assumption in postgres_fdw that when rescanning a
foreign relation, it can rewind the cursor created for scanning the
foreign relation without specifying the SCROLL option, regardless of its
scrollability, causing this error when it tried to do such a rewind in a
non-scrollable cursor.  Fix by modifying postgres_fdw to instead
recreate the cursor, regardless of its scrollability, when rescanning
the foreign relation.  (If we had a way to check its scrollability, we
could improve this by rewinding it if it is scrollable and recreating it
if not, but we do not have it, so this commit modifies it to recreate it
in any case.)

Per bug #17889 from Eric Cyr.  Devrim Gunduz also reported this problem.
Back-patch to v15 where that commit enforced the prohibition.

Reviewed by Tom Lane.

Discussion: https://postgr.es/m/17889-e8c39a251d258dda%40postgresql.org
Discussion: https://postgr.es/m/b415ac3255f8352d1ea921cf3b7ba39e0587768a.camel%40gunduz.org
2024-07-19 13:15:00 +09:00
..
expected postgres_fdw: Avoid "cursor can only scan forward" error. 2024-07-19 13:15:00 +09:00
sql postgres_fdw: Avoid "cursor can only scan forward" error. 2024-07-19 13:15:00 +09:00
.gitignore
connection.c Make postgres_fdw request remote time zone 'GMT' not 'UTC'. 2024-04-21 13:46:20 -04:00
deparse.c Fixup various StringInfo function usages 2024-04-10 11:53:32 +12:00
Makefile postgres_fdw: Add function to list cached connections to foreign servers. 2021-01-18 15:11:08 +09:00
meson.build Update copyright for 2024 2024-01-03 20:49:05 -05:00
option.c Update copyright for 2024 2024-01-03 20:49:05 -05:00
postgres_fdw--1.0--1.1.sql postgres_fdw: Add functions to discard cached connections. 2021-01-26 15:35:54 +09:00
postgres_fdw--1.0.sql
postgres_fdw.c postgres_fdw: Avoid "cursor can only scan forward" error. 2024-07-19 13:15:00 +09:00
postgres_fdw.control postgres_fdw: Add function to list cached connections to foreign servers. 2021-01-18 15:11:08 +09:00
postgres_fdw.h Make dblink interruptible, via new libpqsrv APIs. 2024-01-08 11:39:56 -08:00
shippable.c Update copyright for 2024 2024-01-03 20:49:05 -05:00