https://lists.mysql.com/commits/80079: mysqlhotcopy did not handle the encoding of schema names in the filesystem, so schemas with most non-alphanumeric characters in their name could not be backed up (http://bugs.mysql.com/44278)

mysqlhostcopy.patch

--- mysqlhotcopy.org    2016-05-11 09:31:09.000000000 +0300
+++ mysqlhotcopy        2017-12-13 13:57:51.972468660 +0300
@@ -239,7 +239,7 @@
 $to_other_database=0;
 if (defined($tgt_name) && $tgt_name =~ m:^\w+$: && @db_desc <= 1)
 {
-    $tgt_dirname = "$datadir/$tgt_name";
+    $tgt_dirname = "$datadir/" . encode_identifier_as_filename($tgt_name);
     $to_other_database=1;
 }
 elsif (defined($tgt_name) && ($tgt_name =~ m:/: || $tgt_name eq '.')) {
@@ -310,7 +310,7 @@
     }

     ## get list of files to copy
-    my $db_dir = "$datadir/$db";
+    my $db_dir = "$datadir/" . encode_identifier_as_filename($db);
     opendir(DBDIR, $db_dir )
       or die "Cannot open dir '$db_dir': $!";

@@ -372,13 +372,13 @@
     if ($to_other_database)
     {
       foreach my $rdb ( @db_desc ) {
-       $rdb->{target} = "$tgt_dirname";
+       $rdb->{target} = "$tgt_dirname/" . encode_identifier_as_filename($rdb->{src});
       }
     }
     elsif ($opt{method} =~ /^scp\b/)
     {   # we have to trust scp to hit the target
        foreach my $rdb ( @db_desc ) {
-           $rdb->{target} = "$tgt_dirname/$rdb->{src}";
+           $rdb->{target} = "$tgt_dirname/" . encode_identifier_as_filename($rdb->{src});
        }
     }
     else
@@ -386,7 +386,7 @@
       die "Last argument ($tgt_dirname) is not a directory\n"
        if (!(-e $tgt_dirname && -d $tgt_dirname ) );
       foreach my $rdb ( @db_desc ) {
-       $rdb->{target} = "$tgt_dirname/$rdb->{src}";
+       $rdb->{target} = "$tgt_dirname/" . encode_identifier_as_filename($rdb->{src});
       }
     }
   }
@@ -394,7 +394,7 @@
   die "Error: expected \$opt{suffix} to exist" unless ( exists $opt{suffix} );

   foreach my $rdb ( @db_desc ) {
-    $rdb->{target} = "$datadir/$rdb->{src}$opt{suffix}";
+    $rdb->{target} = "$datadir/" . encode_identifier_as_filename("$rdb->{src}$opt{suffix}");
   }
 }

@@ -439,7 +439,7 @@
             unless -d $tgt_dirpath;
         if ($^O !~ m/^(NetWare)$/)
         {
-            my @f_info= stat "$datadir/$rdb->{src}";
+            my @f_info= stat "$datadir/" . encode_identifier_as_filename($rdb->{src});
             chown $f_info[4], $f_info[5], $tgt_dirpath;
         }
     }
@@ -496,7 +496,7 @@

 foreach my $rdb ( @db_desc )
 {
-  my @files = map { "$datadir/$rdb->{src}/$_" } @{$rdb->{files}};
+  my @files = map { "$datadir/" .encode_identifier_as_filename($rdb->{src}) ."/$_" } @{$rdb->{files}};
   next unless @files;

   eval { copy_files($opt{method}, \@files, $rdb->{target}); };
@@ -507,7 +507,7 @@
   if ($rdb->{index})
   {
     copy_index($opt{method}, \@files,
-              "$datadir/$rdb->{src}", $rdb->{target} );
+              "$datadir/" . encode_identifier_as_filename($rdb->{src}), $rdb->{target} );
   }

   if ( $opt{checkpoint} ) {
@@ -819,6 +819,20 @@
   return "`$db`.`$table`";
 }

+#
+# In MySQL 5.1 and later, directory and table names are encoded on disk.
+# We use the server to figure out the encoded names, and just fall back
+# to the unencoded identifier if that fails.
+#
+sub encode_identifier_as_filename {
+  my ($ident)= @_;
+  my ($filename)= $dbh->selectrow_array(
+                    "SELECT BINARY(CAST(? AS CHAR CHARACTER SET FILENAME))",
+                    { RaiseError => 0 },
+                    $ident);
+  return $filename ? $filename : $ident;
+}
+
 __END__

 =head1 DESCRIPTION