Re: Add pg_freespacemap extension sql test

Michael Paquier <michael(at)paquier(dot)xyz> writes:
> Yes, we could extend that more. For now, I am curious to see what the
> buildfarm has to say with the current contents of the patch, and I can
> keep an eye on the buildfarm today, so I have applied it.

It seems this is unstable under valgrind [1]:

--- /mnt/resource/bf/build/skink-master/HEAD/pgsql/contrib/pg_freespacemap/expected/pg_freespacemap.out 2022-03-24 09:39:43.974477703 +0000
+++ /mnt/resource/bf/build/skink-master/HEAD/pgsql.build/contrib/pg_freespacemap/results/pg_freespacemap.out 2022-03-27 17:07:23.896287669 +0000
@@ -60,6 +60,7 @@
ORDER BY 1, 2;
id | blkno | is_avail
-----------------+-------+----------
+ freespace_tab | 0 | t
freespace_brin | 0 | f
freespace_brin | 1 | f
freespace_brin | 2 | t
@@ -75,7 +76,7 @@
freespace_hash | 7 | f
freespace_hash | 8 | f
freespace_hash | 9 | f
-(15 rows)
+(16 rows)

-- failures with incorrect block number
SELECT * FROM pg_freespace('freespace_tab', -1);

skink has passed several runs since the commit went in, so it's
"unstable" not "fails consistently". I see the test tries to
disable autovacuum on that table, so that doesn't seem to be
the problem ... what is?

regards, tom lane

[1] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=skink&dt=2022-03-27%2008%3A26%3A20