src/test/perl/PostgreSQL/Test/AdjustUpgrade.pm - cloudberry - Git at Google


 # Copyright (c) 2023, PostgreSQL Global Development Group

 =pod

 =head1 NAME

 PostgreSQL::Test::AdjustUpgrade - helper module for cross-version upgrade tests

 =head1 SYNOPSIS

   use PostgreSQL::Test::AdjustUpgrade;

   # Build commands to adjust contents of old-version database before dumping
   $statements = adjust_database_contents($old_version, %dbnames);

   # Adjust contents of old pg_dumpall output file to match newer version
   $dump = adjust_old_dumpfile($old_version, $dump);

   # Adjust contents of new pg_dumpall output file to match older version
   $dump = adjust_new_dumpfile($old_version, $dump);

 =head1 DESCRIPTION

 C<PostgreSQL::Test::AdjustUpgrade> encapsulates various hacks needed to
 compare the results of cross-version upgrade tests.

 =cut

 package PostgreSQL::Test::AdjustUpgrade;

 use strict;
 use warnings;

 use Exporter 'import';
 use PostgreSQL::Version;

 our @EXPORT = qw(
   adjust_database_contents
   adjust_old_dumpfile
   adjust_new_dumpfile
 );

 =pod

 =head1 ROUTINES

 =over

 =item $statements = adjust_database_contents($old_version, %dbnames)

 Generate SQL commands to perform any changes to an old-version installation
 that are needed before we can pg_upgrade it into the current PostgreSQL
 version.

 Typically this involves dropping or adjusting no-longer-supported objects.

 Arguments:

 =over

 =item C<old_version>: Branch we are upgrading from, represented as a
 PostgreSQL::Version object.

 =item C<dbnames>: Hash of database names present in the old installation.

 =back

 Returns a reference to a hash, wherein the keys are database names and the
 values are arrayrefs to lists of statements to be run in those databases.

 =cut

 sub adjust_database_contents
 {
 	my ($old_version, %dbnames) = @_;
 	my $result = {};

 	# remove dbs of modules known to cause pg_upgrade to fail
 	# anything not builtin and incompatible should clean up its own db
 	foreach my $bad_module ('test_ddl_deparse', 'tsearch2')
 	{
 		if ($dbnames{"contrib_regression_$bad_module"})
 		{
 			_add_st($result, 'postgres',
 				"drop database contrib_regression_$bad_module");
 			delete($dbnames{"contrib_regression_$bad_module"});
 		}
 	}

 	# avoid version number issues with test_ext7
 	if ($dbnames{contrib_regression_test_extensions})
 	{
 		_add_st(
 			$result,
 			'contrib_regression_test_extensions',
 			'drop extension if exists test_ext7');
 	}

 	# get rid of dblink's dependencies on regress.so
 	my $regrdb =
 	  $old_version le '9.4'
 	  ? 'contrib_regression'
 	  : 'contrib_regression_dblink';

 	if ($dbnames{$regrdb})
 	{
 		_add_st(
 			$result, $regrdb,
 			'drop function if exists public.putenv(text)',
 			'drop function if exists public.wait_pid(integer)');
 	}

 	# user table OIDs are gone from release 12 on
 	if ($old_version < 12)
 	{
 		my $nooid_stmt = q{
            DO $stmt$
            DECLARE
               rec text;
            BEGIN
               FOR rec in
                  select oid::regclass::text
                  from pg_class
                  where relname !~ '^pg_'
                     and relhasoids
                     and relkind in ('r','m')
                  order by 1
               LOOP
                  execute 'ALTER TABLE ' || rec || ' SET WITHOUT OIDS';
                  RAISE NOTICE 'removing oids from table %', rec;
               END LOOP;
            END; $stmt$;
         };

 		foreach my $oiddb ('regression', 'contrib_regression_btree_gist')
 		{
 			next unless $dbnames{$oiddb};
 			_add_st($result, $oiddb, $nooid_stmt);
 		}

 		# this table had OIDs too, but we'll just drop it
 		if ($old_version >= 10 && $dbnames{'contrib_regression_postgres_fdw'})
 		{
 			_add_st(
 				$result,
 				'contrib_regression_postgres_fdw',
 				'drop foreign table ft_pg_type');
 		}
 	}

 	# abstime+friends are gone from release 12 on; but these tables
 	# might or might not be present depending on regression test vintage
 	if ($old_version < 12)
 	{
 		_add_st($result, 'regression',
 			'drop table if exists abstime_tbl, reltime_tbl, tinterval_tbl');
 	}

 	# some regression functions gone from release 11 on
 	if ($old_version < 11)
 	{
 		_add_st(
 			$result, 'regression',
 			'drop function if exists public.boxarea(box)',
 			'drop function if exists public.funny_dup17()');
 	}

 	# version-0 C functions are no longer supported
 	if ($old_version < 10)
 	{
 		_add_st($result, 'regression',
 			'drop function oldstyle_length(integer, text)');
 	}

 	if ($old_version lt '9.5')
 	{
 		# cope with changes of underlying functions
 		_add_st(
 			$result,
 			'regression',
 			'drop operator @#@ (NONE, bigint)',
 			'CREATE OPERATOR @#@ ('
 			  . 'PROCEDURE = factorial, RIGHTARG = bigint )',
 			'drop aggregate public.array_cat_accum(anyarray)',
 			'CREATE AGGREGATE array_larger_accum (anyarray) ' . ' ( '
 			  . '   sfunc = array_larger, '
 			  . '   stype = anyarray, '
 			  . '   initcond = $${}$$ ' . '  ) ');

 		# "=>" is no longer valid as an operator name
 		_add_st($result, 'regression',
 			'drop operator if exists public.=> (bigint, NONE)');
 	}

 	return $result;
 }

 # Internal subroutine to add statement(s) to the list for the given db.
 sub _add_st
 {
 	my ($result, $db, @st) = @_;

 	$result->{$db} ||= [];
 	push(@{ $result->{$db} }, @st);
 }

 =pod

 =item adjust_old_dumpfile($old_version, $dump)

 Edit a dump output file, taken from the adjusted old-version installation
 by current-version C<pg_dumpall -s>, so that it will match the results of
 C<pg_dumpall -s> on the pg_upgrade'd installation.

 Typically this involves coping with cosmetic differences in the output
 of backend subroutines used by pg_dump.

 Arguments:

 =over

 =item C<old_version>: Branch we are upgrading from, represented as a
 PostgreSQL::Version object.

 =item C<dump>: Contents of dump file

 =back

 Returns the modified dump text.

 =cut

 sub adjust_old_dumpfile
 {
 	my ($old_version, $dump) = @_;

 	# use Unix newlines
 	$dump =~ s/\r\n/\n/g;

 	# Version comments will certainly not match.
 	$dump =~ s/^-- Dumped from database version.*\n//mg;

 	# Change trigger definitions to say ... EXECUTE FUNCTION ...
 	if ($old_version < 12)
 	{
 		# would like to use lookbehind here but perl complains
 		# so do it this way
 		$dump =~ s/
 			(^CREATE\sTRIGGER\s.*?)
 			\sEXECUTE\sPROCEDURE
 			/$1 EXECUTE FUNCTION/mgx;
 	}

 	if ($old_version lt '9.6')
 	{
 		# adjust some places where we don't print so many parens anymore

 		my $prefix =
 		  "'New York'\tnew & york | big & apple | nyc\t'new' & 'york'\t";
 		my $orig = "( 'new' & 'york' | 'big' & 'appl' ) | 'nyc'";
 		my $repl = "'new' & 'york' | 'big' & 'appl' | 'nyc'";
 		$dump =~ s/(?<=^\Q$prefix\E)\Q$orig\E/$repl/mg;

 		$prefix =
 		  "'Sanct Peter'\tPeterburg | peter | 'Sanct Peterburg'\t'sanct' & 'peter'\t";
 		$orig = "( 'peterburg' | 'peter' ) | 'sanct' & 'peterburg'";
 		$repl = "'peterburg' | 'peter' | 'sanct' & 'peterburg'";
 		$dump =~ s/(?<=^\Q$prefix\E)\Q$orig\E/$repl/mg;
 	}

 	# dumps from pre-9.6 databases will show assorted default grants explicitly
 	if ($old_version lt '9.6')
 	{
 		my $comment =
 		  "-- Name: SCHEMA public; Type: ACL; Schema: -; Owner: .*";
 		my $sql =
 		    "REVOKE ALL ON SCHEMA public FROM PUBLIC;\n"
 		  . "REVOKE ALL ON SCHEMA public FROM .*;\n"
 		  . "GRANT ALL ON SCHEMA public TO .*;\n"
 		  . "GRANT ALL ON SCHEMA public TO PUBLIC;";
 		$dump =~ s/^--\n$comment\n--\n+$sql\n+//mg;

 		$comment = "-- Name: DATABASE .*; Type: ACL; Schema: -; Owner: .*";
 		$sql =
 		    "REVOKE ALL ON DATABASE .* FROM PUBLIC;\n"
 		  . "REVOKE ALL ON DATABASE .* FROM .*;\n"
 		  . "GRANT ALL ON DATABASE .* TO .*;\n"
 		  . "GRANT CONNECT,TEMPORARY ON DATABASE .* TO PUBLIC;\n";
 		$dump =~ s/^--\n$comment\n--\n+$sql\n+//mg;
 		$dump =~ s/^$sql//mg;

 		$sql =
 		    "REVOKE ALL ON TABLE .* FROM PUBLIC;\n"
 		  . "REVOKE ALL ON TABLE .* FROM .*;\n"
 		  . "GRANT ALL ON TABLE .* TO .*;\n";
 		$dump =~ s/^$sql//mg;
 	}

 	if ($old_version lt '9.5')
 	{
 		# adjust some places where we don't print so many parens anymore

 		my $prefix = "CONSTRAINT (?:sequence|copy)_con CHECK [(][(]";
 		my $orig   = "((x > 3) AND (y <> 'check failed'::text))";
 		my $repl   = "(x > 3) AND (y <> 'check failed'::text)";
 		$dump =~ s/($prefix)\Q$orig\E/$1$repl/mg;

 		$prefix = "CONSTRAINT insert_con CHECK [(][(]";
 		$orig   = "((x >= 3) AND (y <> 'check failed'::text))";
 		$repl   = "(x >= 3) AND (y <> 'check failed'::text)";
 		$dump =~ s/($prefix)\Q$orig\E/$1$repl/mg;

 		$orig = "DEFAULT ((-1) * currval('public.insert_seq'::regclass))";
 		$repl =
 		  "DEFAULT ('-1'::integer * currval('public.insert_seq'::regclass))";
 		$dump =~ s/\Q$orig\E/$repl/mg;

 		my $expr =
 		  "(rsl.sl_color = rsh.slcolor) AND (rsl.sl_len_cm >= rsh.slminlen_cm)";
 		$dump =~ s/WHERE \(\(\Q$expr\E\)/WHERE ($expr/g;

 		$expr =
 		  "(rule_and_refint_t3.id3a = new.id3a) AND (rule_and_refint_t3.id3b = new.id3b)";
 		$dump =~ s/WHERE \(\(\Q$expr\E\)/WHERE ($expr/g;

 		$expr =
 		  "(rule_and_refint_t3_1.id3a = new.id3a) AND (rule_and_refint_t3_1.id3b = new.id3b)";
 		$dump =~ s/WHERE \(\(\Q$expr\E\)/WHERE ($expr/g;
 	}

 	if ($old_version lt '9.3')
 	{
 		# CREATE VIEW/RULE statements were not pretty-printed before 9.3.
 		# To cope, reduce all whitespace sequences within them to one space.
 		# This must be done on both old and new dumps.
 		$dump = _mash_view_whitespace($dump);

 		# _mash_view_whitespace doesn't handle multi-command rules;
 		# rather than trying to fix that, just hack the exceptions manually.

 		my $prefix =
 		  "CREATE RULE rtest_sys_del AS ON DELETE TO public.rtest_system DO (DELETE FROM public.rtest_interface WHERE (rtest_interface.sysname = old.sysname);";
 		my $line2 = " DELETE FROM public.rtest_admin";
 		my $line3 = " WHERE (rtest_admin.sysname = old.sysname);";
 		$dump =~
 		  s/(?<=\Q$prefix\E)\Q$line2$line3\E \);/\n$line2\n $line3\n);/mg;

 		$prefix =
 		  "CREATE RULE rtest_sys_upd AS ON UPDATE TO public.rtest_system DO (UPDATE public.rtest_interface SET sysname = new.sysname WHERE (rtest_interface.sysname = old.sysname);";
 		$line2 = " UPDATE public.rtest_admin SET sysname = new.sysname";
 		$line3 = " WHERE (rtest_admin.sysname = old.sysname);";
 		$dump =~
 		  s/(?<=\Q$prefix\E)\Q$line2$line3\E \);/\n$line2\n $line3\n);/mg;

 		# and there's one place where pre-9.3 uses a different table alias
 		$dump =~ s {^(CREATE\sRULE\srule_and_refint_t3_ins\sAS\s
 			 ON\sINSERT\sTO\spublic\.rule_and_refint_t3\s
 			 WHERE\s\(EXISTS\s\(SELECT\s1\sFROM\spublic\.rule_and_refint_t3)\s
 			 (WHERE\s\(\(rule_and_refint_t3)
 			 (\.id3a\s=\snew\.id3a\)\sAND\s\(rule_and_refint_t3)
 			 (\.id3b\s=\snew\.id3b\)\sAND\s\(rule_and_refint_t3)}
 		{$1 rule_and_refint_t3_1 $2_1$3_1$4_1}mx;

 		# Also fix old use of NATURAL JOIN syntax
 		$dump =~ s {NATURAL JOIN public\.credit_card r}
 			{JOIN public.credit_card r USING (cid)}mg;
 		$dump =~ s {NATURAL JOIN public\.credit_usage r}
 			{JOIN public.credit_usage r USING (cid)}mg;
 	}

 	# Suppress blank lines, as some places in pg_dump emit more or fewer.
 	$dump =~ s/\n\n+/\n/g;

 	return $dump;
 }

 # Internal subroutine to mangle whitespace within view/rule commands.
 # Any consecutive sequence of whitespace is reduced to one space.
 sub _mash_view_whitespace
 {
 	my ($dump) = @_;

 	foreach my $leader ('CREATE VIEW', 'CREATE RULE')
 	{
 		my @splitchunks = split $leader, $dump;

 		$dump = shift(@splitchunks);
 		foreach my $chunk (@splitchunks)
 		{
 			my @thischunks = split /;/, $chunk, 2;
 			my $stmt = shift(@thischunks);

 			# now $stmt is just the body of the CREATE VIEW/RULE
 			$stmt =~ s/\s+/ /sg;
 			# we also need to smash these forms for sub-selects and rules
 			$stmt =~ s/\( SELECT/(SELECT/g;
 			$stmt =~ s/\( INSERT/(INSERT/g;
 			$stmt =~ s/\( UPDATE/(UPDATE/g;
 			$stmt =~ s/\( DELETE/(DELETE/g;

 			$dump .= $leader . $stmt . ';' . $thischunks[0];
 		}
 	}
 	return $dump;
 }

 =pod

 =item adjust_new_dumpfile($old_version, $dump)

 Edit a dump output file, taken from the pg_upgrade'd installation
 by current-version C<pg_dumpall -s>, so that it will match the old
 dump output file as adjusted by C<adjust_old_dumpfile>.

 Typically this involves deleting data not present in the old installation.

 Arguments:

 =over

 =item C<old_version>: Branch we are upgrading from, represented as a
 PostgreSQL::Version object.

 =item C<dump>: Contents of dump file

 =back

 Returns the modified dump text.

 =cut

 sub adjust_new_dumpfile
 {
 	my ($old_version, $dump) = @_;

 	# use Unix newlines
 	$dump =~ s/\r\n/\n/g;

 	# Version comments will certainly not match.
 	$dump =~ s/^-- Dumped from database version.*\n//mg;

 	# pre-v12 dumps will not say anything about default_table_access_method.
 	if ($old_version < 12)
 	{
 		$dump =~ s/^SET default_table_access_method = heap;\n//mg;
 	}

 	# dumps from pre-9.6 dblink may include redundant ACL settings
 	if ($old_version lt '9.6')
 	{
 		my $comment =
 		  "-- Name: FUNCTION dblink_connect_u\(.*?\); Type: ACL; Schema: public; Owner: .*";
 		my $sql =
 		  "REVOKE ALL ON FUNCTION public\.dblink_connect_u\(.*?\) FROM PUBLIC;";
 		$dump =~ s/^--\n$comment\n--\n+$sql\n+//mg;
 	}

 	if ($old_version lt '9.3')
 	{
 		# CREATE VIEW/RULE statements were not pretty-printed before 9.3.
 		# To cope, reduce all whitespace sequences within them to one space.
 		# This must be done on both old and new dumps.
 		$dump = _mash_view_whitespace($dump);
 	}

 	# Suppress blank lines, as some places in pg_dump emit more or fewer.
 	$dump =~ s/\n\n+/\n/g;

 	return $dump;
 }

 =pod

 =back

 =cut

 1;

	# Copyright (c) 2023, PostgreSQL Global Development Group

	=pod

	=head1 NAME

	PostgreSQL::Test::AdjustUpgrade - helper module for cross-version upgrade tests

	=head1 SYNOPSIS

	use PostgreSQL::Test::AdjustUpgrade;

	# Build commands to adjust contents of old-version database before dumping
	$statements = adjust_database_contents($old_version, %dbnames);

	# Adjust contents of old pg_dumpall output file to match newer version
	$dump = adjust_old_dumpfile($old_version, $dump);

	# Adjust contents of new pg_dumpall output file to match older version
	$dump = adjust_new_dumpfile($old_version, $dump);

	=head1 DESCRIPTION

	C<PostgreSQL::Test::AdjustUpgrade> encapsulates various hacks needed to
	compare the results of cross-version upgrade tests.

	=cut

	package PostgreSQL::Test::AdjustUpgrade;

	use strict;
	use warnings;

	use Exporter 'import';
	use PostgreSQL::Version;

	our @EXPORT = qw(
	adjust_database_contents
	adjust_old_dumpfile
	adjust_new_dumpfile
	);

	=pod

	=head1 ROUTINES

	=over

	=item $statements = adjust_database_contents($old_version, %dbnames)

	Generate SQL commands to perform any changes to an old-version installation
	that are needed before we can pg_upgrade it into the current PostgreSQL
	version.

	Typically this involves dropping or adjusting no-longer-supported objects.

	Arguments:

	=over

	=item C<old_version>: Branch we are upgrading from, represented as a
	PostgreSQL::Version object.

	=item C<dbnames>: Hash of database names present in the old installation.

	=back

	Returns a reference to a hash, wherein the keys are database names and the
	values are arrayrefs to lists of statements to be run in those databases.

	=cut

	sub adjust_database_contents
	{
	my ($old_version, %dbnames) = @_;
	my $result = {};

	# remove dbs of modules known to cause pg_upgrade to fail
	# anything not builtin and incompatible should clean up its own db
	foreach my $bad_module ('test_ddl_deparse', 'tsearch2')
	{
	if ($dbnames{"contrib_regression_$bad_module"})
	{
	_add_st($result, 'postgres',
	"drop database contrib_regression_$bad_module");
	delete($dbnames{"contrib_regression_$bad_module"});
	}
	}

	# avoid version number issues with test_ext7
	if ($dbnames{contrib_regression_test_extensions})
	{
	_add_st(
	$result,
	'contrib_regression_test_extensions',
	'drop extension if exists test_ext7');
	}

	# get rid of dblink's dependencies on regress.so
	my $regrdb =
	$old_version le '9.4'
	? 'contrib_regression'
	: 'contrib_regression_dblink';

	if ($dbnames{$regrdb})
	{
	_add_st(
	$result, $regrdb,
	'drop function if exists public.putenv(text)',
	'drop function if exists public.wait_pid(integer)');
	}

	# user table OIDs are gone from release 12 on
	if ($old_version < 12)
	{
	my $nooid_stmt = q{
	DO $stmt$
	DECLARE
	rec text;
	BEGIN
	FOR rec in
	select oid::regclass::text
	from pg_class
	where relname !~ '^pg_'
	and relhasoids
	and relkind in ('r','m')
	order by 1
	LOOP
	execute 'ALTER TABLE ' \|\| rec \|\| ' SET WITHOUT OIDS';
	RAISE NOTICE 'removing oids from table %', rec;
	END LOOP;
	END; $stmt$;
	};

	foreach my $oiddb ('regression', 'contrib_regression_btree_gist')
	{
	next unless $dbnames{$oiddb};
	_add_st($result, $oiddb, $nooid_stmt);
	}

	# this table had OIDs too, but we'll just drop it
	if ($old_version >= 10 && $dbnames{'contrib_regression_postgres_fdw'})
	{
	_add_st(
	$result,
	'contrib_regression_postgres_fdw',
	'drop foreign table ft_pg_type');
	}
	}

	# abstime+friends are gone from release 12 on; but these tables
	# might or might not be present depending on regression test vintage
	if ($old_version < 12)
	{
	_add_st($result, 'regression',
	'drop table if exists abstime_tbl, reltime_tbl, tinterval_tbl');
	}

	# some regression functions gone from release 11 on
	if ($old_version < 11)
	{
	_add_st(
	$result, 'regression',
	'drop function if exists public.boxarea(box)',
	'drop function if exists public.funny_dup17()');
	}

	# version-0 C functions are no longer supported
	if ($old_version < 10)
	{
	_add_st($result, 'regression',
	'drop function oldstyle_length(integer, text)');
	}

	if ($old_version lt '9.5')
	{
	# cope with changes of underlying functions
	_add_st(
	$result,
	'regression',
	'drop operator @#@ (NONE, bigint)',
	'CREATE OPERATOR @#@ ('
	. 'PROCEDURE = factorial, RIGHTARG = bigint )',
	'drop aggregate public.array_cat_accum(anyarray)',
	'CREATE AGGREGATE array_larger_accum (anyarray) ' . ' ( '
	. ' sfunc = array_larger, '
	. ' stype = anyarray, '
	. ' initcond = $${}$$ ' . ' ) ');

	# "=>" is no longer valid as an operator name
	_add_st($result, 'regression',
	'drop operator if exists public.=> (bigint, NONE)');
	}

	return $result;
	}

	# Internal subroutine to add statement(s) to the list for the given db.
	sub _add_st
	{
	my ($result, $db, @st) = @_;

	$result->{$db} \|\|= [];
	push(@{ $result->{$db} }, @st);
	}

	=pod

	=item adjust_old_dumpfile($old_version, $dump)

	Edit a dump output file, taken from the adjusted old-version installation
	by current-version C<pg_dumpall -s>, so that it will match the results of
	C<pg_dumpall -s> on the pg_upgrade'd installation.

	Typically this involves coping with cosmetic differences in the output
	of backend subroutines used by pg_dump.

	Arguments:

	=over

	=item C<old_version>: Branch we are upgrading from, represented as a
	PostgreSQL::Version object.

	=item C<dump>: Contents of dump file

	=back

	Returns the modified dump text.

	=cut

	sub adjust_old_dumpfile
	{
	my ($old_version, $dump) = @_;

	# use Unix newlines
	$dump =~ s/\r\n/\n/g;

	# Version comments will certainly not match.
	$dump =~ s/^-- Dumped from database version.*\n//mg;

	# Change trigger definitions to say ... EXECUTE FUNCTION ...
	if ($old_version < 12)
	{
	# would like to use lookbehind here but perl complains
	# so do it this way
	$dump =~ s/
	(^CREATE\sTRIGGER\s.*?)
	\sEXECUTE\sPROCEDURE
	/$1 EXECUTE FUNCTION/mgx;
	}

	if ($old_version lt '9.6')
	{
	# adjust some places where we don't print so many parens anymore

	my $prefix =
	"'New York'\tnew & york \| big & apple \| nyc\t'new' & 'york'\t";
	my $orig = "( 'new' & 'york' \| 'big' & 'appl' ) \| 'nyc'";
	my $repl = "'new' & 'york' \| 'big' & 'appl' \| 'nyc'";
	$dump =~ s/(?<=^\Q$prefix\E)\Q$orig\E/$repl/mg;

	$prefix =
	"'Sanct Peter'\tPeterburg \| peter \| 'Sanct Peterburg'\t'sanct' & 'peter'\t";
	$orig = "( 'peterburg' \| 'peter' ) \| 'sanct' & 'peterburg'";
	$repl = "'peterburg' \| 'peter' \| 'sanct' & 'peterburg'";
	$dump =~ s/(?<=^\Q$prefix\E)\Q$orig\E/$repl/mg;
	}

	# dumps from pre-9.6 databases will show assorted default grants explicitly
	if ($old_version lt '9.6')
	{
	my $comment =
	"-- Name: SCHEMA public; Type: ACL; Schema: -; Owner: .*";
	my $sql =
	"REVOKE ALL ON SCHEMA public FROM PUBLIC;\n"
	. "REVOKE ALL ON SCHEMA public FROM .*;\n"
	. "GRANT ALL ON SCHEMA public TO .*;\n"
	. "GRANT ALL ON SCHEMA public TO PUBLIC;";
	$dump =~ s/^--\n$comment\n--\n+$sql\n+//mg;

	$comment = "-- Name: DATABASE .; Type: ACL; Schema: -; Owner: .";
	$sql =
	"REVOKE ALL ON DATABASE .* FROM PUBLIC;\n"
	. "REVOKE ALL ON DATABASE .* FROM .*;\n"
	. "GRANT ALL ON DATABASE .* TO .*;\n"
	. "GRANT CONNECT,TEMPORARY ON DATABASE .* TO PUBLIC;\n";
	$dump =~ s/^--\n$comment\n--\n+$sql\n+//mg;
	$dump =~ s/^$sql//mg;

	$sql =
	"REVOKE ALL ON TABLE .* FROM PUBLIC;\n"
	. "REVOKE ALL ON TABLE .* FROM .*;\n"
	. "GRANT ALL ON TABLE .* TO .*;\n";
	$dump =~ s/^$sql//mg;
	}

	if ($old_version lt '9.5')
	{
	# adjust some places where we don't print so many parens anymore

	my $prefix = "CONSTRAINT (?:sequence\|copy)_con CHECK [(][(]";
	my $orig = "((x > 3) AND (y <> 'check failed'::text))";
	my $repl = "(x > 3) AND (y <> 'check failed'::text)";
	$dump =~ s/($prefix)\Q$orig\E/$1$repl/mg;

	$prefix = "CONSTRAINT insert_con CHECK [(][(]";
	$orig = "((x >= 3) AND (y <> 'check failed'::text))";
	$repl = "(x >= 3) AND (y <> 'check failed'::text)";
	$dump =~ s/($prefix)\Q$orig\E/$1$repl/mg;

	$orig = "DEFAULT ((-1) * currval('public.insert_seq'::regclass))";
	$repl =
	"DEFAULT ('-1'::integer * currval('public.insert_seq'::regclass))";
	$dump =~ s/\Q$orig\E/$repl/mg;

	my $expr =
	"(rsl.sl_color = rsh.slcolor) AND (rsl.sl_len_cm >= rsh.slminlen_cm)";
	$dump =~ s/WHERE \(\(\Q$expr\E\)/WHERE ($expr/g;

	$expr =
	"(rule_and_refint_t3.id3a = new.id3a) AND (rule_and_refint_t3.id3b = new.id3b)";
	$dump =~ s/WHERE \(\(\Q$expr\E\)/WHERE ($expr/g;

	$expr =
	"(rule_and_refint_t3_1.id3a = new.id3a) AND (rule_and_refint_t3_1.id3b = new.id3b)";
	$dump =~ s/WHERE \(\(\Q$expr\E\)/WHERE ($expr/g;
	}

	if ($old_version lt '9.3')
	{
	# CREATE VIEW/RULE statements were not pretty-printed before 9.3.
	# To cope, reduce all whitespace sequences within them to one space.
	# This must be done on both old and new dumps.
	$dump = _mash_view_whitespace($dump);

	# _mash_view_whitespace doesn't handle multi-command rules;
	# rather than trying to fix that, just hack the exceptions manually.

	my $prefix =
	"CREATE RULE rtest_sys_del AS ON DELETE TO public.rtest_system DO (DELETE FROM public.rtest_interface WHERE (rtest_interface.sysname = old.sysname);";
	my $line2 = " DELETE FROM public.rtest_admin";
	my $line3 = " WHERE (rtest_admin.sysname = old.sysname);";
	$dump =~
	s/(?<=\Q$prefix\E)\Q$line2$line3\E \);/\n$line2\n $line3\n);/mg;

	$prefix =
	"CREATE RULE rtest_sys_upd AS ON UPDATE TO public.rtest_system DO (UPDATE public.rtest_interface SET sysname = new.sysname WHERE (rtest_interface.sysname = old.sysname);";
	$line2 = " UPDATE public.rtest_admin SET sysname = new.sysname";
	$line3 = " WHERE (rtest_admin.sysname = old.sysname);";
	$dump =~
	s/(?<=\Q$prefix\E)\Q$line2$line3\E \);/\n$line2\n $line3\n);/mg;

	# and there's one place where pre-9.3 uses a different table alias
	$dump =~ s {^(CREATE\sRULE\srule_and_refint_t3_ins\sAS\s
	ON\sINSERT\sTO\spublic\.rule_and_refint_t3\s
	WHERE\s\(EXISTS\s\(SELECT\s1\sFROM\spublic\.rule_and_refint_t3)\s
	(WHERE\s\(\(rule_and_refint_t3)
	(\.id3a\s=\snew\.id3a\)\sAND\s\(rule_and_refint_t3)
	(\.id3b\s=\snew\.id3b\)\sAND\s\(rule_and_refint_t3)}
	{$1 rule_and_refint_t3_1 $2_1$3_1$4_1}mx;

	# Also fix old use of NATURAL JOIN syntax
	$dump =~ s {NATURAL JOIN public\.credit_card r}
	{JOIN public.credit_card r USING (cid)}mg;
	$dump =~ s {NATURAL JOIN public\.credit_usage r}
	{JOIN public.credit_usage r USING (cid)}mg;
	}

	# Suppress blank lines, as some places in pg_dump emit more or fewer.
	$dump =~ s/\n\n+/\n/g;

	return $dump;
	}

	# Internal subroutine to mangle whitespace within view/rule commands.
	# Any consecutive sequence of whitespace is reduced to one space.
	sub _mash_view_whitespace
	{
	my ($dump) = @_;

	foreach my $leader ('CREATE VIEW', 'CREATE RULE')
	{
	my @splitchunks = split $leader, $dump;

	$dump = shift(@splitchunks);
	foreach my $chunk (@splitchunks)
	{
	my @thischunks = split /;/, $chunk, 2;
	my $stmt = shift(@thischunks);

	# now $stmt is just the body of the CREATE VIEW/RULE
	$stmt =~ s/\s+/ /sg;
	# we also need to smash these forms for sub-selects and rules
	$stmt =~ s/\( SELECT/(SELECT/g;
	$stmt =~ s/\( INSERT/(INSERT/g;
	$stmt =~ s/\( UPDATE/(UPDATE/g;
	$stmt =~ s/\( DELETE/(DELETE/g;

	$dump .= $leader . $stmt . ';' . $thischunks[0];
	}
	}
	return $dump;
	}

	=pod

	=item adjust_new_dumpfile($old_version, $dump)

	Edit a dump output file, taken from the pg_upgrade'd installation
	by current-version C<pg_dumpall -s>, so that it will match the old
	dump output file as adjusted by C<adjust_old_dumpfile>.

	Typically this involves deleting data not present in the old installation.

	Arguments:

	=over

	=item C<old_version>: Branch we are upgrading from, represented as a
	PostgreSQL::Version object.

	=item C<dump>: Contents of dump file

	=back

	Returns the modified dump text.

	=cut

	sub adjust_new_dumpfile
	{
	my ($old_version, $dump) = @_;

	# use Unix newlines
	$dump =~ s/\r\n/\n/g;

	# Version comments will certainly not match.
	$dump =~ s/^-- Dumped from database version.*\n//mg;

	# pre-v12 dumps will not say anything about default_table_access_method.
	if ($old_version < 12)
	{
	$dump =~ s/^SET default_table_access_method = heap;\n//mg;
	}

	# dumps from pre-9.6 dblink may include redundant ACL settings
	if ($old_version lt '9.6')
	{
	my $comment =
	"-- Name: FUNCTION dblink_connect_u\(.?\); Type: ACL; Schema: public; Owner: .";
	my $sql =
	"REVOKE ALL ON FUNCTION public\.dblink_connect_u\(.*?\) FROM PUBLIC;";
	$dump =~ s/^--\n$comment\n--\n+$sql\n+//mg;
	}

	if ($old_version lt '9.3')
	{
	# CREATE VIEW/RULE statements were not pretty-printed before 9.3.
	# To cope, reduce all whitespace sequences within them to one space.
	# This must be done on both old and new dumps.
	$dump = _mash_view_whitespace($dump);
	}

	# Suppress blank lines, as some places in pg_dump emit more or fewer.
	$dump =~ s/\n\n+/\n/g;

	return $dump;
	}

	=pod

	=back

	=cut

	1;