diff --git a/src/test/perl/PostgresNode.pm b/src/test/perl/PostgresNode.pm
index 980f1f1533..5b19c23e50 100644
--- a/src/test/perl/PostgresNode.pm
+++ b/src/test/perl/PostgresNode.pm
@@ -1781,9 +1781,6 @@ sub command_checks_all
 Run a command on the node, then verify that $expected_sql appears in the
 server log file.
 
-Reads the whole log file so be careful when working with large log outputs.
-The log file is truncated prior to running the command, however.
-
 =cut
 
 sub issues_sql_like
@@ -1795,10 +1792,11 @@ sub issues_sql_like
 	local $ENV{PGHOST} = $self->host;
 	local $ENV{PGPORT} = $self->port;
 
-	truncate $self->logfile, 0;
+	my $log_location = -s $self->logfile;
+
 	my $result = TestLib::run_log($cmd);
 	ok($result, "@$cmd exit code 0");
-	my $log = TestLib::slurp_file($self->logfile);
+	my $log = TestLib::slurp_file($self->logfile, $log_location);
 	like($log, $expected_sql, "$test_name: SQL found in server log");
 	return;
 }
diff --git a/src/test/perl/TestLib.pm b/src/test/perl/TestLib.pm
index a7490d2ce7..fecc6733da 100644
--- a/src/test/perl/TestLib.pm
+++ b/src/test/perl/TestLib.pm
@@ -46,7 +46,7 @@ use warnings;
 use Config;
 use Cwd;
 use Exporter 'import';
-use Fcntl qw(:mode);
+use Fcntl qw(:mode :seek);
 use File::Basename;
 use File::Find;
 use File::Spec;
@@ -117,7 +117,7 @@ BEGIN
 	if ($windows_os)
 	{
 		require Win32API::File;
-		Win32API::File->import(qw(createFile OsFHandleOpen CloseHandle));
+		Win32API::File->import(qw(createFile OsFHandleOpen CloseHandle setFilePointer));
 	}
 
 	# Specifies whether to use Unix sockets for test setups.  On
@@ -402,21 +402,27 @@ sub slurp_dir
 
 =pod
 
-=item slurp_file(filename)
+=item slurp_file(filename [, $offset])
 
-Return the full contents of the specified file.
+Return the full contents of the specified file, beginning from an
+offset position if specified.
 
 =cut
 
 sub slurp_file
 {
-	my ($filename) = @_;
+	my ($filename, $offset) = @_;
 	local $/;
 	my $contents;
 	if ($Config{osname} ne 'MSWin32')
 	{
 		open(my $in, '<', $filename)
 		  or die "could not read \"$filename\": $!";
+		if (defined($offset))
+		{
+			seek($in, $offset, SEEK_SET)
+			  or die "could not seek \"$filename\": $!";
+		}
 		$contents = <$in>;
 		close $in;
 	}
@@ -426,6 +432,11 @@ sub slurp_file
 		  or die "could not open \"$filename\": $^E";
 		OsFHandleOpen(my $fh = IO::Handle->new(), $fHandle, 'r')
 		  or die "could not read \"$filename\": $^E\n";
+		if (defined($offset))
+		{
+			setFilePointer($fh, $offset, qw(FILE_BEGIN))
+			  or die "could not seek \"$filename\": $^E\n";
+		}
 		$contents = <$fh>;
 		CloseHandle($fHandle)
 		  or die "could not close \"$filename\": $^E\n";