On 8/3/22 4:19 PM, Tom Lane wrote:
"Jonathan S. Katz" <jk...@postgresql.org> writes:
I did rule out wanting to do the "xid + $X" check after reviewing some
of the output. I think that both $X could end up varying, and it really
feels like a bandaid.
It is that. I wouldn't feel comfortable with $X less than 100 or so,
which is probably sloppy enough to draw Robert's ire. Still, realizing
that what we want right now is a band-aid for 15beta3, I don't think
it's an unreasonable short-term option.
Attached is the "band-aid / sloppy" version of the patch. Given from the
test examples I kept seeing deltas over 100 for relfrozenxid, I chose
1000. The mxid delta was less, but I kept it at 1000 for consistency
(and because I hope this test is short lived in this state), but can be
talked into otherwise.
Andres suggested upthread using "txid_current()" -- for the comparison,
that's one thing I looked at. Would any of the XID info from
"pg_control_checkpoint()" also serve for this test?
I like the idea of txid_current(), but we have no comparable
function for mxid do we? While you could get both numbers from
pg_control_checkpoint(), I doubt that's sufficiently up-to-date.
...unless we force a checkpoint in the test?
Jonathan
diff --git a/src/bin/pg_upgrade/t/002_pg_upgrade.pl
b/src/bin/pg_upgrade/t/002_pg_upgrade.pl
index 4cbc75644c..ced889601f 100644
--- a/src/bin/pg_upgrade/t/002_pg_upgrade.pl
+++ b/src/bin/pg_upgrade/t/002_pg_upgrade.pl
@@ -226,6 +226,8 @@ ORDER BY c.oid::regclass::text
EOM
$horizon_query =~ s/\s+/ /g; # run it together on one line
my $horizon1 = $oldnode->safe_psql('regression', $horizon_query);
+chomp($horizon1);
+my @horizon1_values = split(/\|/, $horizon1);
# In a VPATH build, we'll be started in the source directory, but we want
# to run pg_upgrade in the build directory so that any files generated finish
@@ -313,6 +315,8 @@ $newnode->command_ok(
# And record the horizons from the upgraded cluster as well.
my $horizon2 = $newnode->safe_psql('regression', $horizon_query);
+chomp($horizon2);
+my @horizon2_values = split(/\|/, $horizon2);
# Compare the two dumps, there should be no differences.
my $compare_res = compare("$tempdir/dump1.sql", "$tempdir/dump2.sql");
@@ -331,8 +335,13 @@ if ($compare_res != 0)
print "=== EOF ===\n";
}
-# Compare the horizons, there should be no differences.
-my $horizons_ok = $horizon1 eq $horizon2;
+# Compare the horizons. There should be no change in the OID, so we will test
+# for equality. However, because autovacuum may have run between the two
+# horizions, we will check if the updated horizon XIDs are greater than or
+# equal to the originals.
+my $horizons_ok = $horizon2_values[0] eq $horizon1_values[0] &&
+ int($horizon2_values[1]) <= int($horizon1_values[1]) + 1000 &&
+ int($horizon2_values[2]) <= int($horizon1_values[2]) + 1000;
ok($horizons_ok, 'old and new horizons match after pg_upgrade');
# Provide more context if the horizons do not match.
