On Wed, Aug 5, 2020 at 4:19 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> After thinking about it for a little bit, I'm envisioning a test module
> that can be loaded into a session, and then it gets into the planner_hook,
> and what it does is after each planner execution, take and release an
> advisory lock with some selectable ID. Then we can construct
> isolationtester specs that do something like
>
> session 1 session 2
>
> LOAD test-module;
> SET custom_guc_for_lock_id = n;
> prepare test tables;
>
> SELECT pg_advisory_lock(n);
>
> SELECT victim-query-here;
> ... after planning, query blocks on lock
>
> perform DDL changes;
> SELECT pg_advisory_unlock(n);
>
> ... query executes with now-stale plan
Very sneaky!
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
