BF failure: could not open relation with OID XXXX while querying pg_views

Hi,

Here are three strange recent failures in the "rules" test:

https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=blenny&dt=2019-08-13%2022:19:27
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=alewife&dt=2019-07-27%2009:39:05
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=dory&dt=2019-07-18%2003:00:27

They all raised "ERROR:  could not open relation with OID <varies>"
while running:

 SELECT viewname, definition FROM pg_views
 WHERE schemaname IN ('pg_catalog', 'public')
 ORDER BY viewname;

-- 
Thomas Munro
https://enterprisedb.com