[Tom Lane <tgl@sss.pgh.pa.us>]

Every once in awhile we get failures like this one:

https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=gull&dt=2019-11-05%2008%3A27%3A27

inline patch 1: /home/pgsql/build-farm/buildroot-clang/HEAD/pgsql.build/src/test/regress/results/vacuum.out (+1/-0 lines) download inline-1.patchdiff -U3 /home/pgsql/build-farm/buildroot-clang/HEAD/pgsql.build/../pgsql/src/test/regress/expected/vacuum.out /home/pgsql/build-farm/buildroot-clang/HEAD/pgsql.build/src/test/regress/results/vacuum.out
--- /home/pgsql/build-farm/buildroot-clang/HEAD/pgsql.build/../pgsql/src/test/regress/expected/vacuum.out	2019-08-11 03:02:18.921535948 -0700
+++ /home/pgsql/build-farm/buildroot-clang/HEAD/pgsql.build/src/test/regress/results/vacuum.out	2019-11-05 00:50:42.381244885 -0800
@@ -204,6 +204,7 @@
 -- SKIP_LOCKED option
 VACUUM (SKIP_LOCKED) vactst;
 VACUUM (SKIP_LOCKED, FULL) vactst;
+WARNING:  skipping vacuum of "vactst" --- lock not available
 ANALYZE (SKIP_LOCKED) vactst;
 -- ensure VACUUM and ANALYZE don't have a problem with serializable
 SET default_transaction_isolation = serializable;


No doubt this is a conflict with autovacuum.  There are two reasonable
ways to remove the test instability:

* Crank up client_min_messages to more than WARNING for this test
stanza.

* Downgrade the "skipping" messages to DEBUG1 or less.

I kind of wonder why we are issuing a "WARNING" when the statement
does exactly what you asked it to, anyway.  At most I'd expect
that to be a NOTICE condition.

			regards, tom lane