pgsql: Fix multiple problems in postgres_fdw query cancellation logic.

pgsql: Fix multiple problems in postgres_fdw query cancellation logic.

Fix multiple problems in postgres_fdw query cancellation logic.

First, even if we cancel a query, we still have to roll back the
containing transaction; otherwise, the session will be left in a
failed transaction state.

Second, we need to support canceling queries whe aborting a
subtransaction as well as when aborting a toplevel transaction.

Etsuro Fujita, reviewed by Michael Paquier

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/1b812afb0eafe125b820cc3b95e7ca03821aa675

Modified Files
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contrib/postgres_fdw/connection.c | 28 +++++++++++++++++++++++++---
1 file changed, 25 insertions(+), 3 deletions(-)