Fix superuser concurrent refresh of matview owned by another.

Kevin Grittner <kgrittn@postgresql.org>

Commit: a9d0f1cff3fb10151be05be61d24ac9b680c170c
Author: Kevin Grittner <kgrittn@postgresql.org>
Date: 2014-08-26T14:56:26Z
Releases: 9.5.0
Fix superuser concurrent refresh of matview owned by another.

Use SECURITY_LOCAL_USERID_CHANGE while building temporary tables;
only escalate to SECURITY_RESTRICTED_OPERATION while potentially
running user-supplied code.  The more secure mode was preventing
temp table creation.  Add regression tests to cover this problem.

This fixes Bug #11208 reported by Bruno Emanuel de Andrade Silva.

Backpatch to 9.4, where the bug was introduced.

Files