skip-sparc-wal-read-bug-v1.patch

Author:     Noah Misch <noah@leadboat.com>
Commit:     Noah Misch <noah@leadboat.com>

    On sparc64+ext4, skip tests that expect flakes from WAL read failure.
    
    Buildfarm member kittiwake began to fail frequently when commits
    3cd9c3b921977272e6650a5efbeade4203c4bca2 and
    f47ed79cc8a0cfa154dc7f01faaf59822552363f added tests of concurrency, but
    the problem was reachable before those commits.  Back-patch to v10 (all
    supported versions).
    
    Reviewed by FIXME.
    
    Discussion: https://postgr.es/m/20220116210241.GC756210@rfd.leadboat.com

diff --git a/contrib/amcheck/t/003_cic_2pc.pl b/contrib/amcheck/t/003_cic_2pc.pl
index dfe7f0f..9ef3d49 100644
--- a/contrib/amcheck/t/003_cic_2pc.pl
+++ b/contrib/amcheck/t/003_cic_2pc.pl
@@ -9,7 +9,16 @@ use Config;
 use PostgreSQL::Test::Cluster;
 use PostgreSQL::Test::Utils;
 
-use Test::More tests => 5;
+use Test::More;
+
+if (PostgreSQL::Test::Utils::has_wal_read_bug)
+{
+	plan skip_all => 'filesystem bug';
+}
+else
+{
+	plan tests => 5;
+}
 
 my ($node, $result);
 
diff --git a/src/test/perl/PostgreSQL/Test/Utils.pm b/src/test/perl/PostgreSQL/Test/Utils.pm
index 50be10f..cbd2cb3 100644
--- a/src/test/perl/PostgreSQL/Test/Utils.pm
+++ b/src/test/perl/PostgreSQL/Test/Utils.pm
@@ -351,6 +351,29 @@ sub perl2host
 
 =pod
 
+=item has_wal_read_bug()
+
+Returns true if $tmp_check is subject to a sparc64+ext4 bug that causes WAL
+readers to see zeros if another process simultaneously wrote the same offsets.
+Use this to skip tests that fail frequently on affected configurations.  The
+bug has made streaming standbys fail to advance, reporting corrupt WAL.  It
+has made COMMIT PREPARED fail with "could not read two-phase state from WAL".
+Non-WAL PostgreSQL reads haven't been affected, likely because those readers
+and writers have buffering systems in common.  See
+https://postgr.es/m/20220116210241.GC756210@rfd.leadboat.com for details.
+
+=cut
+
+sub has_wal_read_bug
+{
+	return
+	     $Config{osname} eq 'linux'
+	  && $Config{archname} =~ /^sparc/
+	  && !run_log([ qw(df -x ext4), $tmp_check ], '>', '/dev/null', '2>&1');
+}
+
+=pod
+
 =item system_log(@cmd)
 
 Run (via C<system()>) the command passed as argument; the return
diff --git a/src/test/recovery/t/027_stream_regress.pl b/src/test/recovery/t/027_stream_regress.pl
index 8c0a8b6..2bb83d3 100644
--- a/src/test/recovery/t/027_stream_regress.pl
+++ b/src/test/recovery/t/027_stream_regress.pl
@@ -3,9 +3,18 @@ use strict;
 use warnings;
 use PostgreSQL::Test::Cluster;
 use PostgreSQL::Test::Utils;
-use Test::More tests => 4;
+use Test::More;
 use File::Basename;
 
+if (PostgreSQL::Test::Utils::has_wal_read_bug)
+{
+	plan skip_all => 'filesystem bug';
+}
+else
+{
+	plan tests => 4;
+}
+
 # Initialize primary node
 my $node_primary = PostgreSQL::Test::Cluster->new('primary');
 $node_primary->init(allows_streaming => 1);