diff --git a/bin/pt-table-checksum b/bin/pt-table-checksum
index 03d086a3..196a8d10 100755
--- a/bin/pt-table-checksum
+++ b/bin/pt-table-checksum
@@ -1602,6 +1602,43 @@ sub join_quote {
    return $db ? "$db.$tbl" : $tbl;
 }
 
+sub serialize_list {
+   my ( $self, @args ) = @_;
+   if ( @args && $args[-1] eq '' ) {
+      push @args, '';
+   }
+   return join ',', map { quotemeta } @args;
+}
+
+sub deserialize_list {
+   my ( $self, $string ) = @_;
+   my @escaped_parts = $string =~ /
+         \G             # Start of string, or end of previous match.
+         (              # Each of these is an element in the original list.
+            [^\\,]*     # Anything not a backslash or a comma
+            (?:         # When we get here, we found one of the above.
+               \\.      # A backslash followed by something so we can continue
+               [^\\,]*  # Same as above.
+            )*          # Repeat zero of more times.
+         )
+         ,?             # Comma dividing elements or absolute end of the string.
+      /sxg;
+
+   pop @escaped_parts;
+
+   my @unescaped_parts = map {
+      my $part = $_;
+
+      my $char_class = utf8::is_utf8($part)  # If it's a UTF-8 string,
+                     ? qr/(?=\p{ASCII})\W/   # We only care about non-word
+                     : qr/(?=\p{ASCII})\W|[\x{80}-\x{FF}]/; # Otherwise,
+      $part =~ s/\\($char_class)/$1/g;
+      $part;
+   } @escaped_parts;
+
+   return @unescaped_parts;
+}
+
 1;
 }
 # ###########################################################################
@@ -6753,8 +6790,8 @@ sub exec_nibble {
    my $dbh         = $cxn->dbh();
    my $sth         = $nibble_iter->statements();
    my $boundary    = $nibble_iter->boundaries();
-   my $lb_quoted   = join(',', @{$boundary->{lower}});
-   my $ub_quoted   = join(',', @{$boundary->{upper}});
+   my $lb_quoted   = $q->serialize_list(@{$boundary->{lower}});
+   my $ub_quoted   = $q->serialize_list(@{$boundary->{upper}});
    my $chunk       = $nibble_iter->nibble_number();
    my $chunk_index = $nibble_iter->nibble_index();
 
diff --git a/bin/pt-table-sync b/bin/pt-table-sync
index b423de98..d9307fa6 100755
--- a/bin/pt-table-sync
+++ b/bin/pt-table-sync
@@ -1104,6 +1104,43 @@ sub join_quote {
    return $db ? "$db.$tbl" : $tbl;
 }
 
+sub serialize_list {
+   my ( $self, @args ) = @_;
+   if ( @args && $args[-1] eq '' ) {
+      push @args, '';
+   }
+   return join ',', map { quotemeta } @args;
+}
+
+sub deserialize_list {
+   my ( $self, $string ) = @_;
+   my @escaped_parts = $string =~ /
+         \G             # Start of string, or end of previous match.
+         (              # Each of these is an element in the original list.
+            [^\\,]*     # Anything not a backslash or a comma
+            (?:         # When we get here, we found one of the above.
+               \\.      # A backslash followed by something so we can continue
+               [^\\,]*  # Same as above.
+            )*          # Repeat zero of more times.
+         )
+         ,?             # Comma dividing elements or absolute end of the string.
+      /sxg;
+
+   pop @escaped_parts;
+
+   my @unescaped_parts = map {
+      my $part = $_;
+
+      my $char_class = utf8::is_utf8($part)  # If it's a UTF-8 string,
+                     ? qr/(?=\p{ASCII})\W/   # We only care about non-word
+                     : qr/(?=\p{ASCII})\W|[\x{80}-\x{FF}]/; # Otherwise,
+      $part =~ s/\\($char_class)/$1/g;
+      $part;
+   } @escaped_parts;
+
+   return @unescaped_parts;
+}
+
 1;
 }
 # ###########################################################################
@@ -8847,16 +8884,14 @@ sub diff_where {
       MKDEBUG && _d('Ascend params:', Dumper($asc));
    }
 
-   my @lb = split ',', $diff->{lower_boundary};
    my $lb_sql = $asc->{boundaries}->{'>='};
-   foreach my $val (@lb) {
+   foreach my $val ( $q->deserialize_list($diff->{lower_boundary}) ) {
       my $quoted_val = $q->quote_val($val);
       $lb_sql =~ s/\?/$val/;
    }
 
-   my @ub = split ',', $diff->{upper_boundary};
    my $ub_sql = $asc->{boundaries}->{'<='};
-   foreach my $val (@ub) {
+   foreach my $val ( $q->deserialize_list($diff->{upper_boundary}) ) {
       my $quoted_val = $q->quote_val($val);
       $ub_sql =~ s/\?/$val/;
    }
diff --git a/t/lib/Quoter.t b/t/lib/Quoter.t
index a876659f..49bab7dd 100644
--- a/t/lib/Quoter.t
+++ b/t/lib/Quoter.t
@@ -9,7 +9,7 @@ BEGIN {
 use strict;
 use warnings FATAL => 'all';
 use English qw(-no_match_vars);
-use Test::More tests => 47;
+use Test::More tests => 52;
 
 use Quoter;
 use PerconaTest;
@@ -103,6 +103,24 @@ is( $q->join_quote('`db`', '`foo`.`tbl`'), '`foo`.`tbl`', 'join_merge(`db`, `foo
 # (de)serialize_list
 # ###########################################################################
 
+is(
+   $q->serialize_list(),
+   undef,
+   "Serialize empty list"
+);
+
+is(
+   $q->serialize_list(''),
+   '',
+   "Serialize 1 empty string",
+);
+
+is(
+   $q->serialize_list('', '', ''),
+   ',,',
+   "Serialize 3 empty strings",
+);
+
 my @serialize_tests = (
    [ 'a', 'b', ],
    [ 'a,', 'b', ],
@@ -120,6 +138,8 @@ my @serialize_tests = (
    [ 1, 2 ],
    [ 7, 9 ],
    [ '', '', '', ],
+   [ '' ],
+   [ undef ],
 );
 
 use DSNParser;