diff --git a/bin/pt-archiver b/bin/pt-archiver
index e4ed893c..0cf1f490 100755
--- a/bin/pt-archiver
+++ b/bin/pt-archiver
@@ -3136,6 +3136,7 @@ sub generate_asc_stmt {
             cols        => \@cols,
             quoter      => $q,
             is_nullable => $tbl_struct->{is_nullable},
+            type_for    => $tbl_struct->{type_for},
          );
          $asc_stmt->{boundaries}->{$cmp} = $cmp_where->{where};
       }
@@ -3156,6 +3157,7 @@ sub generate_cmp_where {
    my @slice       = @{$args{slice}};
    my @cols        = @{$args{cols}};
    my $is_nullable = $args{is_nullable};
+   my $type_for    = $args{type_for};
    my $type        = $args{type};
    my $q           = $self->{Quoter};
 
@@ -3172,13 +3174,14 @@ sub generate_cmp_where {
          my $ord = $slice[$j];
          my $col = $cols[$ord];
          my $quo = $q->quote($col);
+         my $val = ($col && ($type_for->{$col} || '')) eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
          if ( $is_nullable->{$col} ) {
-            push @clause, "((? IS NULL AND $quo IS NULL) OR ($quo = ?))";
+            push @clause, "(($val IS NULL AND $quo IS NULL) OR ($quo = $val))";
             push @r_slice, $ord, $ord;
             push @r_scols, $col, $col;
          }
          else {
-            push @clause, "$quo = ?";
+            push @clause, "$quo = $val";
             push @r_slice, $ord;
             push @r_scols, $col;
          }
@@ -3188,15 +3191,16 @@ sub generate_cmp_where {
       my $col = $cols[$ord];
       my $quo = $q->quote($col);
       my $end = $i == $#slice; # Last clause of the whole group.
+      my $val = ($col && ($type_for->{$col} || '')) eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
       if ( $is_nullable->{$col} ) {
          if ( $type =~ m/=/ && $end ) {
-            push @clause, "(? IS NULL OR $quo $type ?)";
+            push @clause, "($val IS NULL OR $quo $type $val)";
          }
          elsif ( $type =~ m/>/ ) {
-            push @clause, "((? IS NULL AND $quo IS NOT NULL) OR ($quo $cmp ?))";
+            push @clause, "(($val IS NULL AND $quo IS NOT NULL) OR ($quo $cmp $val)";
          }
          else { # If $type =~ m/</ ) {
-            push @clause, "((? IS NOT NULL AND $quo IS NULL) OR ($quo $cmp ?))";
+            push @clauses, "(($val IS NOT NULL AND $quo IS NULL) OR ($quo $cmp $val))";
          }
          push @r_slice, $ord, $ord;
          push @r_scols, $col, $col;
@@ -3204,7 +3208,7 @@ sub generate_cmp_where {
       else {
          push @r_slice, $ord;
          push @r_scols, $col;
-         push @clause, ($type =~ m/=/ && $end ? "$quo $type ?" : "$quo $cmp ?");
+         push @clause, ($type =~ m/=/ && $end ? "$quo $type $val" : "$quo $cmp $val");
       }
 
       push @clauses, '(' . join(' AND ', @clause) . ')';
diff --git a/bin/pt-online-schema-change b/bin/pt-online-schema-change
index a1d968c1..3e4a3521 100755
--- a/bin/pt-online-schema-change
+++ b/bin/pt-online-schema-change
@@ -3057,15 +3057,13 @@ sub generate_cmp_where {
          my $ord = $slice[$j];
          my $col = $cols[$ord];
          my $quo = $q->quote($col);
-         my $val = $type_for->{$col} eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
+         my $val = ($col && ($type_for->{$col} || '')) eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
          if ( $is_nullable->{$col} ) {
-             #push @clause, "((? IS NULL AND $quo IS NULL) OR ($quo = ?))";
             push @clause, "(($val IS NULL AND $quo IS NULL) OR ($quo = $val))";
             push @r_slice, $ord, $ord;
             push @r_scols, $col, $col;
          }
          else {
-             #push @clause, "$quo = ?";
             push @clause, "$quo = $val";
             push @r_slice, $ord;
             push @r_scols, $col;
@@ -3076,18 +3074,15 @@ sub generate_cmp_where {
       my $col = $cols[$ord];
       my $quo = $q->quote($col);
       my $end = $i == $#slice; # Last clause of the whole group.
-      my $val = $type_for->{$col} eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
+      my $val = ($col && ($type_for->{$col} || '')) eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
       if ( $is_nullable->{$col} ) {
          if ( $type =~ m/=/ && $end ) {
-             #push @clause, "(? IS NULL OR $quo $type ?)";
             push @clause, "($val IS NULL OR $quo $type $val)";
          }
          elsif ( $type =~ m/>/ ) {
-            #push @clause, "((? IS NULL AND $quo IS NOT NULL) OR ($quo $cmp ?))";
             push @clause, "(($val IS NULL AND $quo IS NOT NULL) OR ($quo $cmp $val)";
          }
          else { # If $type =~ m/</ ) {
-             #push @clause, "((? IS NOT NULL AND $quo IS NULL) OR ($quo $cmp ?))";
             push @clauses, "(($val IS NOT NULL AND $quo IS NULL) OR ($quo $cmp $val))";
          }
          push @r_slice, $ord, $ord;
@@ -3096,7 +3091,6 @@ sub generate_cmp_where {
       else {
          push @r_slice, $ord;
          push @r_scols, $col;
-         #push @clause, ($type =~ m/=/ && $end ? "$quo $type ?" : "$quo $cmp ?");
          push @clause, ($type =~ m/=/ && $end ? "$quo $type $val" : "$quo $cmp $val");
       }
 
@@ -5457,7 +5451,6 @@ use strict;
 use warnings FATAL => 'all';
 use English qw(-no_match_vars);
 use constant PTDEBUG => $ENV{PTDEBUG} || 0;
-use IndexLength;
 
 use Data::Dumper;
 $Data::Dumper::Indent    = 1;
@@ -5495,82 +5488,131 @@ sub new {
    my @cols       = grep { !$ignore_col->{$_} } @$all_cols;
    my $self;
    if ( $nibble_params->{one_nibble} ) {
+      my $params = _one_nibble(\%args, \@cols, $where, $tbl, \%comments);
+      $self = {
+         %args,
+         one_nibble         => 1,
+         limit              => 0,
+         nibble_sql         => $params->{nibble_sql},
+         explain_nibble_sql => $params->{explain_nibble_sql},
+      };
+   } else {
+      my $params = _nibble_params($nibble_params, $tbl, \%args, \@cols, $chunk_size, $where, \%comments, $q);
+      $self = {
+         %args,
+         index                => $params->{index},
+         limit                => $params->{limit},
+         first_lb_sql         => $params->{first_lb_sql},
+         last_ub_sql          => $params->{last_ub_sql},
+         ub_sql               => $params->{ub_sql},
+         nibble_sql           => $params->{nibble_sql},
+         explain_first_lb_sql => $params->{explain_first_lb_sql},
+         explain_ub_sql       => $params->{explain_ub_sql},
+         explain_nibble_sql   => $params->{explain_nibble_sql},
+         resume_lb_sql        => $params->{resume_lb_sql},
+         sql                  => $params->{sql},
+      };
+   }
+
+   $self->{row_est}    = $nibble_params->{row_est},
+   $self->{nibbleno}   = 0;
+   $self->{have_rows}  = 0;
+   $self->{rowno}      = 0;
+   $self->{oktonibble} = 1;
+   $self->{pause_file} = $nibble_params->{pause_file};
+   $self->{sleep}      = $args{sleep} || 60;
+
+   $self->{nibble_params} = $nibble_params;
+   $self->{tbl}           = $tbl;
+   $self->{args}          = \%args;
+   $self->{cols}          = \@cols;
+   $self->{chunk_size}    = $chunk_size;
+   $self->{where}         = $where;
+   $self->{comments}      = \%comments;
+
+   return bless $self, $class;
+}
+
+sub switch_to_nibble {
+    my $self = shift;
+    my $params = _nibble_params($self->{nibble_params}, $self->{tbl}, $self->{args}, $self->{cols}, 
+                                $self->{chunk_size}, $self->{where}, $self->{comments}, $self->{Quoter});
+
+    $self->{one_nibble}           = 0;
+    $self->{index}                = $params->{index};
+    $self->{limit}                = $params->{limit};
+    $self->{first_lb_sql}         = $params->{first_lb_sql};
+    $self->{last_ub_sql}          = $params->{last_ub_sql};
+    $self->{ub_sql}               = $params->{ub_sql};
+    $self->{nibble_sql}           = $params->{nibble_sql};
+    $self->{explain_first_lb_sql} = $params->{explain_first_lb_sql};
+    $self->{explain_ub_sql}       = $params->{explain_ub_sql};
+    $self->{explain_nibble_sql}   = $params->{explain_nibble_sql};
+    $self->{resume_lb_sql}        = $params->{resume_lb_sql};
+    $self->{sql}                  = $params->{sql};
+    $self->_get_bounds();
+    $self->_prepare_sths();
+}
+
+sub _one_nibble {
+    my ($args, $cols, $where, $tbl, $comments) = @_;
+    my $q        = new Quoter();
+
       my $nibble_sql
-         = ($args{dml} ? "$args{dml} " : "SELECT ")
-         . ($args{select} ? $args{select}
-                          : join(', ', map { $q->quote($_) } @cols))
+         = ($args->{dml} ? "$args->{dml} " : "SELECT ")
+         . ($args->{select} ? $args->{select}
+         : join(', ', map{ $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ?
+                                   "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_) } @$cols))
          . " FROM $tbl->{name}"
          . ($where ? " WHERE $where" : '')
-         . ($args{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
-         . " /*$comments{bite}*/";
+         . ($args->{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
+         . " /*$comments->{bite}*/";
       PTDEBUG && _d('One nibble statement:', $nibble_sql);
 
       my $explain_nibble_sql
          = "EXPLAIN SELECT "
-         . ($args{select} ? $args{select}
-                          : join(', ', map { $q->quote($_) } @cols))
+         . ($args->{select} ? $args->{select}
+                          : join(', ', map{ $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' 
+                          ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_) } @$cols))
          . " FROM $tbl->{name}"
          . ($where ? " WHERE $where" : '')
-         . ($args{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
-         . " /*explain $comments{bite}*/";
+         . ($args->{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
+         . " /*explain $comments->{bite}*/";
       PTDEBUG && _d('Explain one nibble statement:', $explain_nibble_sql);
 
-      $self = {
-         %args,
+      return {
          one_nibble         => 1,
          limit              => 0,
          nibble_sql         => $nibble_sql,
          explain_nibble_sql => $explain_nibble_sql,
       };
-   }
-   else {
+}
+
+sub _nibble_params {
+      my ($nibble_params, $tbl, $args, $cols, $chunk_size, $where, $comments, $q) = @_;
       my $index      = $nibble_params->{index}; # brevity
       my $index_cols = $tbl->{tbl_struct}->{keys}->{$index}->{cols};
 
-      my $asc = $args{TableNibbler}->generate_asc_stmt(
-         %args,
+      my $asc = $args->{TableNibbler}->generate_asc_stmt(
+         %$args,
          tbl_struct   => $tbl->{tbl_struct},
          index        => $index,
-         n_index_cols => $args{n_chunk_index_cols},
-         cols         => \@cols,
+         n_index_cols => $args->{n_chunk_index_cols},
+         cols         => $cols,
          asc_only     => 1,
       );
       PTDEBUG && _d('Ascend params:', Dumper($asc));
 
-      my $force_concat_enums = $o->has('force-concat-enums') && $o->get('force-concat-enums');
-      my $i=0;
-      for my $index (@{$index_cols}) {
-          last if $args{n_chunk_index_cols} && $i >= $args{n_chunk_index_cols};
-          $i++;
-          if ($tbl->{tbl_struct}->{type_for}->{$index} eq 'enum') {
-             if ($tbl->{tbl_struct}->{defs}->{$index} =~ m/enum\s*\((.*?)\)/) {
-                 my @items = split(/,\s*/, $1);
-                 my $sorted = 1; # Asume the items list is sorted to later check if this is true
-                 for (my $i=1; $i < scalar(@items); $i++) {
-                     if ($items[$i-1] gt $items[$i]) {
-                         $sorted = 0;
-                         last;
-                     }
-                 }
-                 if (!$force_concat_enums && !$sorted) {
-                    die "The index " . $index . " in table " .  $tbl->{name} .
-                    " has unsorted enum items.\nPlease read the documentation for the --force-concat-enums parameter\n";
-                 }
-             }
-          }
-      }
+      my $force_concat_enums;
 
 
       my $from     = "$tbl->{name} FORCE INDEX(`$index`)";
-      my $order_by = join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' && $force_concat_enums
-                                        ? "CONCAT(".$q->quote($_).")" : $q->quote($_)} @{$index_cols});
-
-      my $order_by_dec = join(' DESC,', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' && $force_concat_enums
-                                        ? "CONCAT(".$q->quote($_).")" : $q->quote($_)} @{$index_cols});
+      my $order_by = join(', ', map {$q->quote($_)} @{$index_cols});
+      my $order_by_dec = join(' DESC,', map {$q->quote($_)} @{$index_cols});
 
       my $first_lb_sql
          = "SELECT /*!40001 SQL_NO_CACHE */ "
-         . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+         . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
          . " FROM $from"
          . ($where ? " WHERE $where" : '')
          . " ORDER BY $order_by"
@@ -5579,10 +5621,10 @@ sub new {
       PTDEBUG && _d('First lower boundary statement:', $first_lb_sql);
 
       my $resume_lb_sql;
-      if ( $args{resume} ) {
+      if ( $args->{resume} ) {
          $resume_lb_sql
             = "SELECT /*!40001 SQL_NO_CACHE */ "
-            . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+            . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
             . " FROM $from"
             . " WHERE " . $asc->{boundaries}->{'>'}
             . ($where ? " AND ($where)" : '')
@@ -5594,7 +5636,7 @@ sub new {
 
       my $last_ub_sql
          = "SELECT /*!40001 SQL_NO_CACHE */ "
-         . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+         . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
          . " FROM $from"
          . ($where ? " WHERE $where" : '')
          . " ORDER BY "
@@ -5605,7 +5647,7 @@ sub new {
 
       my $ub_sql
          = "SELECT /*!40001 SQL_NO_CACHE */ "
-         . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+         . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
          . " FROM $from"
          . " WHERE " . $asc->{boundaries}->{'>='}
                      . ($where ? " AND ($where)" : '')
@@ -5615,36 +5657,36 @@ sub new {
       PTDEBUG && _d('Upper boundary statement:', $ub_sql);
 
       my $nibble_sql
-         = ($args{dml} ? "$args{dml} " : "SELECT ")
-         . ($args{select} ? $args{select}
-                          : join(', ', map { $q->quote($_) } @{$asc->{cols}}))
+         = ($args->{dml} ? "$args->{dml} " : "SELECT ")
+         . ($args->{select} ? $args->{select}
+                          : join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{cols}}))
          . " FROM $from"
          . " WHERE " . $asc->{boundaries}->{'>='}  # lower boundary
          . " AND "   . $asc->{boundaries}->{'<='}  # upper boundary
          . ($where ? " AND ($where)" : '')
-         . ($args{order_by} ? " ORDER BY $order_by" : "")
-         . ($args{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
-         . " /*$comments{nibble}*/";
+         . ($args->{order_by} ? " ORDER BY $order_by" : "")
+         . ($args->{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
+         . " /*$comments->{nibble}*/";
       PTDEBUG && _d('Nibble statement:', $nibble_sql);
 
       my $explain_nibble_sql 
          = "EXPLAIN SELECT "
-         . ($args{select} ? $args{select}
+         . ($args->{select} ? $args->{select}
                           : join(', ', map { $q->quote($_) } @{$asc->{cols}}))
          . " FROM $from"
          . " WHERE " . $asc->{boundaries}->{'>='}  # lower boundary
          . " AND "   . $asc->{boundaries}->{'<='}  # upper boundary
          . ($where ? " AND ($where)" : '')
-         . ($args{order_by} ? " ORDER BY $order_by" : "")
-         . ($args{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
-         . " /*explain $comments{nibble}*/";
+         . ($args->{order_by} ? " ORDER BY $order_by" : "")
+         . ($args->{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
+         . " /*explain $comments->{nibble}*/";
       PTDEBUG && _d('Explain nibble statement:', $explain_nibble_sql);
 
       my $limit = $chunk_size - 1;
       PTDEBUG && _d('Initial chunk size (LIMIT):', $limit);
 
-      $self = {
-         %args,
+      my $params = {
+         one_nibble           => 0,
          index                => $index,
          limit                => $limit,
          first_lb_sql         => $first_lb_sql,
@@ -5663,17 +5705,7 @@ sub new {
             order_by   => $order_by,
          },
       };
-   }
-
-   $self->{row_est}    = $nibble_params->{row_est},
-   $self->{nibbleno}   = 0;
-   $self->{have_rows}  = 0;
-   $self->{rowno}      = 0;
-   $self->{oktonibble} = 1;
-   $self->{pause_file} = $nibble_params->{pause_file};
-   $self->{sleep}      = $args{sleep} || 60;
-
-   return bless $self, $class;
+      return $params;
 }
 
 sub next {
@@ -5710,7 +5742,6 @@ sub next {
 
    NIBBLE:
    while ( $self->{have_rows} || $self->_next_boundaries() ) {
-
       if ($self->{pause_file}) {
          while(-f $self->{pause_file}) {
             print "Sleeping $self->{sleep} seconds because $self->{pause_file} exists\n";
@@ -5822,12 +5853,8 @@ sub set_boundary {
 }
 
 sub one_nibble {
-   my ($self, $value) = @_;
-   if (@_ == 2) {
-       $self->{one_nibble} = $value;
-   } else {
-       return $self->{one_nibble};
-   }
+   my ($self) = @_;
+   return $self->{one_nibble};
 }
 
 sub limit {
@@ -5861,11 +5888,11 @@ sub row_estimate {
 
 sub can_nibble {
    my (%args) = @_;
-   my @required_args = qw(Cxn tbl chunk_size OptionParser TableParser Quoter);
+   my @required_args = qw(Cxn tbl chunk_size OptionParser TableParser);
    foreach my $arg ( @required_args ) {
       die "I need a $arg argument" unless $args{$arg};
    }
-   my ($cxn, $tbl, $chunk_size, $o, $q) = @args{@required_args};
+   my ($cxn, $tbl, $chunk_size, $o) = @args{@required_args};
 
    my $where = $o->has('where') ? $o->get('where') : '';
 
@@ -5875,23 +5902,6 @@ sub can_nibble {
       where => $where,
    );
 
-   my $can_get_keys;
-   if ($mysql_index) {
-       my $idx_len = IndexLength->new(Quoter => $q);
-       my ($key_len, $key) = $idx_len->index_length(
-           Cxn          => $args{Cxn},
-           tbl          => $tbl,
-           index        => $mysql_index,
-           n_index_cols => $o->get('chunk-index-columns'),
-       );
-
-       if ( !$key || !$key_len || lc($key) ne lc($mysql_index)) {
-           $can_get_keys = 0;
-       } else {
-           $can_get_keys = 1;
-       }
-   } 
-
    if ( !$where ) {
       $mysql_index = undef;
    }
@@ -5900,10 +5910,6 @@ sub can_nibble {
    my $one_nibble = !defined $args{one_nibble} || $args{one_nibble}
                   ? $row_est <= $chunk_size * $chunk_size_limit
                   : 0;
-   if (!$can_get_keys) {
-       $one_nibble = 1;
-   }
-
    PTDEBUG && _d('One nibble:', $one_nibble ? 'yes' : 'no');
 
    if ( $args{resume}
@@ -6659,6 +6665,7 @@ use English qw(-no_match_vars);
 use constant PTDEBUG => $ENV{PTDEBUG} || 0;
 
 use Data::Dumper;
+use Carp;
 $Data::Dumper::Indent    = 1;
 $Data::Dumper::Sortkeys  = 1;
 $Data::Dumper::Quotekeys = 0;
@@ -6671,7 +6678,7 @@ sub new {
    }
 
    my $self = {
-      Quoter => $args{Quoter},
+       Quoter => $args{Quoter},
    };
 
    return bless $self, $class;
@@ -6728,8 +6735,16 @@ sub _get_first_values {
 
    my $index_struct  = $tbl->{tbl_struct}->{keys}->{$index};
    my $index_cols    = $index_struct->{cols};
-   my $index_columns = join (', ',
+   my $index_columns;
+   eval {
+   $index_columns = join (', ',
       map { $q->quote($_) } @{$index_cols}[0..($n_index_cols - 1)]);
+  };
+  if ($EVAL_ERROR) {
+      confess "$EVAL_ERROR";
+  }
+
+
 
    my @where;
    foreach my $col ( @{$index_cols}[0..($n_index_cols - 1)] ) {
@@ -6763,8 +6778,7 @@ sub _make_range_query {
    if ( $n_index_cols > 1 ) {
       foreach my $n ( 0..($n_index_cols - 2) ) {
          my $col = $index_cols->[$n];
-         my $val = $vals->[$n];
-         $val = $tbl->{tbl_struct}->{type_for}->{$col} eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
+         my $val = $tbl->{tbl_struct}->{type_for}->{$col} eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
          push @where, $q->quote($col) . " = " . $val;
       }
    }
@@ -9620,11 +9634,14 @@ sub main {
                      . " * chunk size limit=$limit).\n";
                warn $msg;
                $failed_to_nibble = 1;
-               $nibble_iter->one_nibble(0); # disable nibbling for this table
+               warn "Switching to nibble\n";
+               $nibble_iter->switch_to_nibble();
                # die ts($msg);
+            } else {
+               return 0;
             }
          }
-         if (!$nibble_iter->one_nibble() || $failed_to_nibble) { # chunking the table
+         if (!$nibble_iter->one_nibble()) { # chunking the table
             if ( $o->get('check-plan') ) {
                my $idx_len = new IndexLength(Quoter => $q);
                my ($key_len, $key) = $idx_len->index_length(
diff --git a/bin/pt-table-checksum b/bin/pt-table-checksum
index cc15207b..5e2bc0e6 100755
--- a/bin/pt-table-checksum
+++ b/bin/pt-table-checksum
@@ -4892,6 +4892,7 @@ sub generate_asc_stmt {
             cols        => \@cols,
             quoter      => $q,
             is_nullable => $tbl_struct->{is_nullable},
+            type_for    => $tbl_struct->{type_for},
          );
          $asc_stmt->{boundaries}->{$cmp} = $cmp_where->{where};
       }
@@ -4912,6 +4913,7 @@ sub generate_cmp_where {
    my @slice       = @{$args{slice}};
    my @cols        = @{$args{cols}};
    my $is_nullable = $args{is_nullable};
+   my $type_for    = $args{type_for};
    my $type        = $args{type};
    my $q           = $self->{Quoter};
 
@@ -4928,13 +4930,14 @@ sub generate_cmp_where {
          my $ord = $slice[$j];
          my $col = $cols[$ord];
          my $quo = $q->quote($col);
+         my $val = ($col && ($type_for->{$col} || '')) eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
          if ( $is_nullable->{$col} ) {
-            push @clause, "((? IS NULL AND $quo IS NULL) OR ($quo = ?))";
+            push @clause, "(($val IS NULL AND $quo IS NULL) OR ($quo = $val))";
             push @r_slice, $ord, $ord;
             push @r_scols, $col, $col;
          }
          else {
-            push @clause, "$quo = ?";
+            push @clause, "$quo = $val";
             push @r_slice, $ord;
             push @r_scols, $col;
          }
@@ -4944,15 +4947,16 @@ sub generate_cmp_where {
       my $col = $cols[$ord];
       my $quo = $q->quote($col);
       my $end = $i == $#slice; # Last clause of the whole group.
+      my $val = ($col && ($type_for->{$col} || '')) eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
       if ( $is_nullable->{$col} ) {
          if ( $type =~ m/=/ && $end ) {
-            push @clause, "(? IS NULL OR $quo $type ?)";
+            push @clause, "($val IS NULL OR $quo $type $val)";
          }
          elsif ( $type =~ m/>/ ) {
-            push @clause, "((? IS NULL AND $quo IS NOT NULL) OR ($quo $cmp ?))";
+            push @clause, "(($val IS NULL AND $quo IS NOT NULL) OR ($quo $cmp $val)";
          }
          else { # If $type =~ m/</ ) {
-            push @clause, "((? IS NOT NULL AND $quo IS NULL) OR ($quo $cmp ?))";
+            push @clauses, "(($val IS NOT NULL AND $quo IS NULL) OR ($quo $cmp $val))";
          }
          push @r_slice, $ord, $ord;
          push @r_scols, $col, $col;
@@ -4960,7 +4964,7 @@ sub generate_cmp_where {
       else {
          push @r_slice, $ord;
          push @r_scols, $col;
-         push @clause, ($type =~ m/=/ && $end ? "$quo $type ?" : "$quo $cmp ?");
+         push @clause, ($type =~ m/=/ && $end ? "$quo $type $val" : "$quo $cmp $val");
       }
 
       push @clauses, '(' . join(' AND ', @clause) . ')';
@@ -6293,7 +6297,6 @@ use strict;
 use warnings FATAL => 'all';
 use English qw(-no_match_vars);
 use constant PTDEBUG => $ENV{PTDEBUG} || 0;
-use IndexLength;
 
 use Data::Dumper;
 $Data::Dumper::Indent    = 1;
@@ -6331,82 +6334,131 @@ sub new {
    my @cols       = grep { !$ignore_col->{$_} } @$all_cols;
    my $self;
    if ( $nibble_params->{one_nibble} ) {
+      my $params = _one_nibble(\%args, \@cols, $where, $tbl, \%comments);
+      $self = {
+         %args,
+         one_nibble         => 1,
+         limit              => 0,
+         nibble_sql         => $params->{nibble_sql},
+         explain_nibble_sql => $params->{explain_nibble_sql},
+      };
+   } else {
+      my $params = _nibble_params($nibble_params, $tbl, \%args, \@cols, $chunk_size, $where, \%comments, $q);
+      $self = {
+         %args,
+         index                => $params->{index},
+         limit                => $params->{limit},
+         first_lb_sql         => $params->{first_lb_sql},
+         last_ub_sql          => $params->{last_ub_sql},
+         ub_sql               => $params->{ub_sql},
+         nibble_sql           => $params->{nibble_sql},
+         explain_first_lb_sql => $params->{explain_first_lb_sql},
+         explain_ub_sql       => $params->{explain_ub_sql},
+         explain_nibble_sql   => $params->{explain_nibble_sql},
+         resume_lb_sql        => $params->{resume_lb_sql},
+         sql                  => $params->{sql},
+      };
+   }
+
+   $self->{row_est}    = $nibble_params->{row_est},
+   $self->{nibbleno}   = 0;
+   $self->{have_rows}  = 0;
+   $self->{rowno}      = 0;
+   $self->{oktonibble} = 1;
+   $self->{pause_file} = $nibble_params->{pause_file};
+   $self->{sleep}      = $args{sleep} || 60;
+
+   $self->{nibble_params} = $nibble_params;
+   $self->{tbl}           = $tbl;
+   $self->{args}          = \%args;
+   $self->{cols}          = \@cols;
+   $self->{chunk_size}    = $chunk_size;
+   $self->{where}         = $where;
+   $self->{comments}      = \%comments;
+
+   return bless $self, $class;
+}
+
+sub switch_to_nibble {
+    my $self = shift;
+    my $params = _nibble_params($self->{nibble_params}, $self->{tbl}, $self->{args}, $self->{cols}, 
+                                $self->{chunk_size}, $self->{where}, $self->{comments}, $self->{Quoter});
+
+    $self->{one_nibble}           = 0;
+    $self->{index}                = $params->{index};
+    $self->{limit}                = $params->{limit};
+    $self->{first_lb_sql}         = $params->{first_lb_sql};
+    $self->{last_ub_sql}          = $params->{last_ub_sql};
+    $self->{ub_sql}               = $params->{ub_sql};
+    $self->{nibble_sql}           = $params->{nibble_sql};
+    $self->{explain_first_lb_sql} = $params->{explain_first_lb_sql};
+    $self->{explain_ub_sql}       = $params->{explain_ub_sql};
+    $self->{explain_nibble_sql}   = $params->{explain_nibble_sql};
+    $self->{resume_lb_sql}        = $params->{resume_lb_sql};
+    $self->{sql}                  = $params->{sql};
+    $self->_get_bounds();
+    $self->_prepare_sths();
+}
+
+sub _one_nibble {
+    my ($args, $cols, $where, $tbl, $comments) = @_;
+    my $q        = new Quoter();
+
       my $nibble_sql
-         = ($args{dml} ? "$args{dml} " : "SELECT ")
-         . ($args{select} ? $args{select}
-                          : join(', ', map { $q->quote($_) } @cols))
+         = ($args->{dml} ? "$args->{dml} " : "SELECT ")
+         . ($args->{select} ? $args->{select}
+         : join(', ', map{ $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ?
+                                   "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_) } @$cols))
          . " FROM $tbl->{name}"
          . ($where ? " WHERE $where" : '')
-         . ($args{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
-         . " /*$comments{bite}*/";
+         . ($args->{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
+         . " /*$comments->{bite}*/";
       PTDEBUG && _d('One nibble statement:', $nibble_sql);
 
       my $explain_nibble_sql
          = "EXPLAIN SELECT "
-         . ($args{select} ? $args{select}
-                          : join(', ', map { $q->quote($_) } @cols))
+         . ($args->{select} ? $args->{select}
+                          : join(', ', map{ $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' 
+                          ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_) } @$cols))
          . " FROM $tbl->{name}"
          . ($where ? " WHERE $where" : '')
-         . ($args{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
-         . " /*explain $comments{bite}*/";
+         . ($args->{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
+         . " /*explain $comments->{bite}*/";
       PTDEBUG && _d('Explain one nibble statement:', $explain_nibble_sql);
 
-      $self = {
-         %args,
+      return {
          one_nibble         => 1,
          limit              => 0,
          nibble_sql         => $nibble_sql,
          explain_nibble_sql => $explain_nibble_sql,
       };
-   }
-   else {
+}
+
+sub _nibble_params {
+      my ($nibble_params, $tbl, $args, $cols, $chunk_size, $where, $comments, $q) = @_;
       my $index      = $nibble_params->{index}; # brevity
       my $index_cols = $tbl->{tbl_struct}->{keys}->{$index}->{cols};
 
-      my $asc = $args{TableNibbler}->generate_asc_stmt(
-         %args,
+      my $asc = $args->{TableNibbler}->generate_asc_stmt(
+         %$args,
          tbl_struct   => $tbl->{tbl_struct},
          index        => $index,
-         n_index_cols => $args{n_chunk_index_cols},
-         cols         => \@cols,
+         n_index_cols => $args->{n_chunk_index_cols},
+         cols         => $cols,
          asc_only     => 1,
       );
       PTDEBUG && _d('Ascend params:', Dumper($asc));
 
-      my $force_concat_enums = $o->has('force-concat-enums') && $o->get('force-concat-enums');
-      my $i=0;
-      for my $index (@{$index_cols}) {
-          last if $args{n_chunk_index_cols} && $i >= $args{n_chunk_index_cols};
-          $i++;
-          if ($tbl->{tbl_struct}->{type_for}->{$index} eq 'enum') {
-             if ($tbl->{tbl_struct}->{defs}->{$index} =~ m/enum\s*\((.*?)\)/) {
-                 my @items = split(/,\s*/, $1);
-                 my $sorted = 1; # Asume the items list is sorted to later check if this is true
-                 for (my $i=1; $i < scalar(@items); $i++) {
-                     if ($items[$i-1] gt $items[$i]) {
-                         $sorted = 0;
-                         last;
-                     }
-                 }
-                 if (!$force_concat_enums && !$sorted) {
-                    die "The index " . $index . " in table " .  $tbl->{name} .
-                    " has unsorted enum items.\nPlease read the documentation for the --force-concat-enums parameter\n";
-                 }
-             }
-          }
-      }
+      my $force_concat_enums;
 
 
       my $from     = "$tbl->{name} FORCE INDEX(`$index`)";
-      my $order_by = join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' && $force_concat_enums
-                                        ? "CONCAT(".$q->quote($_).")" : $q->quote($_)} @{$index_cols});
-
-      my $order_by_dec = join(' DESC,', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' && $force_concat_enums
-                                        ? "CONCAT(".$q->quote($_).")" : $q->quote($_)} @{$index_cols});
+      my $order_by = join(', ', map {$q->quote($_)} @{$index_cols});
+      my $order_by_dec = join(' DESC,', map {$q->quote($_)} @{$index_cols});
 
       my $first_lb_sql
          = "SELECT /*!40001 SQL_NO_CACHE */ "
-         . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+         . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
          . " FROM $from"
          . ($where ? " WHERE $where" : '')
          . " ORDER BY $order_by"
@@ -6415,10 +6467,10 @@ sub new {
       PTDEBUG && _d('First lower boundary statement:', $first_lb_sql);
 
       my $resume_lb_sql;
-      if ( $args{resume} ) {
+      if ( $args->{resume} ) {
          $resume_lb_sql
             = "SELECT /*!40001 SQL_NO_CACHE */ "
-            . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+            . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
             . " FROM $from"
             . " WHERE " . $asc->{boundaries}->{'>'}
             . ($where ? " AND ($where)" : '')
@@ -6430,7 +6482,7 @@ sub new {
 
       my $last_ub_sql
          = "SELECT /*!40001 SQL_NO_CACHE */ "
-         . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+         . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
          . " FROM $from"
          . ($where ? " WHERE $where" : '')
          . " ORDER BY "
@@ -6441,7 +6493,7 @@ sub new {
 
       my $ub_sql
          = "SELECT /*!40001 SQL_NO_CACHE */ "
-         . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+         . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
          . " FROM $from"
          . " WHERE " . $asc->{boundaries}->{'>='}
                      . ($where ? " AND ($where)" : '')
@@ -6451,36 +6503,36 @@ sub new {
       PTDEBUG && _d('Upper boundary statement:', $ub_sql);
 
       my $nibble_sql
-         = ($args{dml} ? "$args{dml} " : "SELECT ")
-         . ($args{select} ? $args{select}
-                          : join(', ', map { $q->quote($_) } @{$asc->{cols}}))
+         = ($args->{dml} ? "$args->{dml} " : "SELECT ")
+         . ($args->{select} ? $args->{select}
+                          : join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{cols}}))
          . " FROM $from"
          . " WHERE " . $asc->{boundaries}->{'>='}  # lower boundary
          . " AND "   . $asc->{boundaries}->{'<='}  # upper boundary
          . ($where ? " AND ($where)" : '')
-         . ($args{order_by} ? " ORDER BY $order_by" : "")
-         . ($args{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
-         . " /*$comments{nibble}*/";
+         . ($args->{order_by} ? " ORDER BY $order_by" : "")
+         . ($args->{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
+         . " /*$comments->{nibble}*/";
       PTDEBUG && _d('Nibble statement:', $nibble_sql);
 
       my $explain_nibble_sql 
          = "EXPLAIN SELECT "
-         . ($args{select} ? $args{select}
+         . ($args->{select} ? $args->{select}
                           : join(', ', map { $q->quote($_) } @{$asc->{cols}}))
          . " FROM $from"
          . " WHERE " . $asc->{boundaries}->{'>='}  # lower boundary
          . " AND "   . $asc->{boundaries}->{'<='}  # upper boundary
          . ($where ? " AND ($where)" : '')
-         . ($args{order_by} ? " ORDER BY $order_by" : "")
-         . ($args{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
-         . " /*explain $comments{nibble}*/";
+         . ($args->{order_by} ? " ORDER BY $order_by" : "")
+         . ($args->{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
+         . " /*explain $comments->{nibble}*/";
       PTDEBUG && _d('Explain nibble statement:', $explain_nibble_sql);
 
       my $limit = $chunk_size - 1;
       PTDEBUG && _d('Initial chunk size (LIMIT):', $limit);
 
-      $self = {
-         %args,
+      my $params = {
+         one_nibble           => 0,
          index                => $index,
          limit                => $limit,
          first_lb_sql         => $first_lb_sql,
@@ -6499,17 +6551,7 @@ sub new {
             order_by   => $order_by,
          },
       };
-   }
-
-   $self->{row_est}    = $nibble_params->{row_est},
-   $self->{nibbleno}   = 0;
-   $self->{have_rows}  = 0;
-   $self->{rowno}      = 0;
-   $self->{oktonibble} = 1;
-   $self->{pause_file} = $nibble_params->{pause_file};
-   $self->{sleep}      = $args{sleep} || 60;
-
-   return bless $self, $class;
+      return $params;
 }
 
 sub next {
@@ -6546,7 +6588,6 @@ sub next {
 
    NIBBLE:
    while ( $self->{have_rows} || $self->_next_boundaries() ) {
-
       if ($self->{pause_file}) {
          while(-f $self->{pause_file}) {
             print "Sleeping $self->{sleep} seconds because $self->{pause_file} exists\n";
@@ -6658,12 +6699,8 @@ sub set_boundary {
 }
 
 sub one_nibble {
-   my ($self, $value) = @_;
-   if (@_ == 2) {
-       $self->{one_nibble} = $value;
-   } else {
-       return $self->{one_nibble};
-   }
+   my ($self) = @_;
+   return $self->{one_nibble};
 }
 
 sub limit {
@@ -6697,11 +6734,11 @@ sub row_estimate {
 
 sub can_nibble {
    my (%args) = @_;
-   my @required_args = qw(Cxn tbl chunk_size OptionParser TableParser Quoter);
+   my @required_args = qw(Cxn tbl chunk_size OptionParser TableParser);
    foreach my $arg ( @required_args ) {
       die "I need a $arg argument" unless $args{$arg};
    }
-   my ($cxn, $tbl, $chunk_size, $o, $q) = @args{@required_args};
+   my ($cxn, $tbl, $chunk_size, $o) = @args{@required_args};
 
    my $where = $o->has('where') ? $o->get('where') : '';
 
@@ -6711,23 +6748,6 @@ sub can_nibble {
       where => $where,
    );
 
-   my $can_get_keys;
-   if ($mysql_index) {
-       my $idx_len = IndexLength->new(Quoter => $q);
-       my ($key_len, $key) = $idx_len->index_length(
-           Cxn          => $args{Cxn},
-           tbl          => $tbl,
-           index        => $mysql_index,
-           n_index_cols => $o->get('chunk-index-columns'),
-       );
-
-       if ( !$key || !$key_len || lc($key) ne lc($mysql_index)) {
-           $can_get_keys = 0;
-       } else {
-           $can_get_keys = 1;
-       }
-   } 
-
    if ( !$where ) {
       $mysql_index = undef;
    }
@@ -6736,10 +6756,6 @@ sub can_nibble {
    my $one_nibble = !defined $args{one_nibble} || $args{one_nibble}
                   ? $row_est <= $chunk_size * $chunk_size_limit
                   : 0;
-   if (!$can_get_keys) {
-       $one_nibble = 1;
-   }
-
    PTDEBUG && _d('One nibble:', $one_nibble ? 'yes' : 'no');
 
    if ( $args{resume}
@@ -9606,6 +9622,7 @@ use English qw(-no_match_vars);
 use constant PTDEBUG => $ENV{PTDEBUG} || 0;
 
 use Data::Dumper;
+use Carp;
 $Data::Dumper::Indent    = 1;
 $Data::Dumper::Sortkeys  = 1;
 $Data::Dumper::Quotekeys = 0;
@@ -9618,7 +9635,7 @@ sub new {
    }
 
    my $self = {
-      Quoter => $args{Quoter},
+       Quoter => $args{Quoter},
    };
 
    return bless $self, $class;
@@ -9670,11 +9687,21 @@ sub _get_first_values {
       die "I need a $arg argument" unless $args{$arg};
    }
    my ($cxn, $tbl, $index, $n_index_cols) = @args{@required_args};
-   my $q  = new Quoter();
+
+   my $q = $self->{Quoter};
+
    my $index_struct  = $tbl->{tbl_struct}->{keys}->{$index};
    my $index_cols    = $index_struct->{cols};
-   my $index_columns = join (', ',
+   my $index_columns;
+   eval {
+   $index_columns = join (', ',
       map { $q->quote($_) } @{$index_cols}[0..($n_index_cols - 1)]);
+  };
+  if ($EVAL_ERROR) {
+      confess "$EVAL_ERROR";
+  }
+
+
 
    my @where;
    foreach my $col ( @{$index_cols}[0..($n_index_cols - 1)] ) {
@@ -9686,19 +9713,21 @@ sub _get_first_values {
            . "WHERE " . join(' AND ', @where)
            . " ORDER BY $index_columns "
            . "LIMIT 1 /*key_len*/";  # only need 1 row
-   PTDEBUG && _d("_get_first_values: $sql");
+   PTDEBUG && _d($sql);
    my $vals = $cxn->dbh()->selectrow_arrayref($sql);
    return $vals;
 }
 
 sub _make_range_query {
    my ($self, %args) = @_;
-   my @required_args = qw(tbl index n_index_cols);
+   my @required_args = qw(tbl index n_index_cols vals);
    foreach my $arg ( @required_args ) {
       die "I need a $arg argument" unless $args{$arg};
    }
    my ($tbl, $index, $n_index_cols, $vals) = @args{@required_args};
-   my $q  = new Quoter();
+
+   my $q = $self->{Quoter};
+
    my $index_struct = $tbl->{tbl_struct}->{keys}->{$index};
    my $index_cols   = $index_struct->{cols};
 
@@ -9706,12 +9735,15 @@ sub _make_range_query {
    if ( $n_index_cols > 1 ) {
       foreach my $n ( 0..($n_index_cols - 2) ) {
          my $col = $index_cols->[$n];
-         push @where, $q->quote($col) . " = ?";
+         my $val = $tbl->{tbl_struct}->{type_for}->{$col} eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
+         push @where, $q->quote($col) . " = " . $val;
       }
    }
 
    my $col = $index_cols->[$n_index_cols - 1];
-   push @where, $q->quote($col) . " >= ?";
+   my $val = $vals->[-1];  # should only be as many vals as cols
+   my $condition = $tbl->{tbl_struct}->{type_for}->{$col} eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
+   push @where, $q->quote($col) . " >= " . $condition;
 
    my $sql = "EXPLAIN SELECT /*!40001 SQL_NO_CACHE */ * "
            . "FROM $tbl->{name} FORCE INDEX (" . $q->quote($index) . ") "
diff --git a/bin/pt-table-sync b/bin/pt-table-sync
index 5ddba648..9ec71806 100755
--- a/bin/pt-table-sync
+++ b/bin/pt-table-sync
@@ -6437,6 +6437,7 @@ sub generate_asc_stmt {
             cols        => \@cols,
             quoter      => $q,
             is_nullable => $tbl_struct->{is_nullable},
+            type_for    => $tbl_struct->{type_for},
          );
          $asc_stmt->{boundaries}->{$cmp} = $cmp_where->{where};
       }
@@ -6457,6 +6458,7 @@ sub generate_cmp_where {
    my @slice       = @{$args{slice}};
    my @cols        = @{$args{cols}};
    my $is_nullable = $args{is_nullable};
+   my $type_for    = $args{type_for};
    my $type        = $args{type};
    my $q           = $self->{Quoter};
 
@@ -6473,13 +6475,14 @@ sub generate_cmp_where {
          my $ord = $slice[$j];
          my $col = $cols[$ord];
          my $quo = $q->quote($col);
+         my $val = ($col && ($type_for->{$col} || '')) eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
          if ( $is_nullable->{$col} ) {
-            push @clause, "((? IS NULL AND $quo IS NULL) OR ($quo = ?))";
+            push @clause, "(($val IS NULL AND $quo IS NULL) OR ($quo = $val))";
             push @r_slice, $ord, $ord;
             push @r_scols, $col, $col;
          }
          else {
-            push @clause, "$quo = ?";
+            push @clause, "$quo = $val";
             push @r_slice, $ord;
             push @r_scols, $col;
          }
@@ -6489,15 +6492,16 @@ sub generate_cmp_where {
       my $col = $cols[$ord];
       my $quo = $q->quote($col);
       my $end = $i == $#slice; # Last clause of the whole group.
+      my $val = ($col && ($type_for->{$col} || '')) eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
       if ( $is_nullable->{$col} ) {
          if ( $type =~ m/=/ && $end ) {
-            push @clause, "(? IS NULL OR $quo $type ?)";
+            push @clause, "($val IS NULL OR $quo $type $val)";
          }
          elsif ( $type =~ m/>/ ) {
-            push @clause, "((? IS NULL AND $quo IS NOT NULL) OR ($quo $cmp ?))";
+            push @clause, "(($val IS NULL AND $quo IS NOT NULL) OR ($quo $cmp $val)";
          }
          else { # If $type =~ m/</ ) {
-            push @clause, "((? IS NOT NULL AND $quo IS NULL) OR ($quo $cmp ?))";
+            push @clauses, "(($val IS NOT NULL AND $quo IS NULL) OR ($quo $cmp $val))";
          }
          push @r_slice, $ord, $ord;
          push @r_scols, $col, $col;
@@ -6505,7 +6509,7 @@ sub generate_cmp_where {
       else {
          push @r_slice, $ord;
          push @r_scols, $col;
-         push @clause, ($type =~ m/=/ && $end ? "$quo $type ?" : "$quo $cmp ?");
+         push @clause, ($type =~ m/=/ && $end ? "$quo $type $val" : "$quo $cmp $val");
       }
 
       push @clauses, '(' . join(' AND ', @clause) . ')';
diff --git a/lib/IndexLength.pm b/lib/IndexLength.pm
index d160a257..8b65216d 100644
--- a/lib/IndexLength.pm
+++ b/lib/IndexLength.pm
@@ -151,8 +151,8 @@ sub _make_range_query {
       # we don't want the last column; that's added below.
       foreach my $n ( 0..($n_index_cols - 2) ) {
          my $col = $index_cols->[$n];
-         my $val = $vals->[$n];
-         push @where, $q->quote($col) . " = ?";
+         my $val = $tbl->{tbl_struct}->{type_for}->{$col} eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
+         push @where, $q->quote($col) . " = " . $val;
       }
    }
 
@@ -160,7 +160,8 @@ sub _make_range_query {
    # the N left-most index columns.
    my $col = $index_cols->[$n_index_cols - 1];
    my $val = $vals->[-1];  # should only be as many vals as cols
-   push @where, $q->quote($col) . " >= ?";
+   my $condition = $tbl->{tbl_struct}->{type_for}->{$col} eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
+   push @where, $q->quote($col) . " >= " . $condition;
 
    my $sql = "EXPLAIN SELECT /*!40001 SQL_NO_CACHE */ * "
            . "FROM $tbl->{name} FORCE INDEX (" . $q->quote($index) . ") "
diff --git a/lib/NibbleIterator.pm b/lib/NibbleIterator.pm
index 8376a831..8662b252 100644
--- a/lib/NibbleIterator.pm
+++ b/lib/NibbleIterator.pm
@@ -139,6 +139,7 @@ sub switch_to_nibble {
     my $params = _nibble_params($self->{nibble_params}, $self->{tbl}, $self->{args}, $self->{cols}, 
                                 $self->{chunk_size}, $self->{where}, $self->{comments}, $self->{Quoter});
 
+    $self->{one_nibble}           = 0;
     $self->{index}                = $params->{index};
     $self->{limit}                = $params->{limit};
     $self->{first_lb_sql}         = $params->{first_lb_sql};
@@ -150,6 +151,8 @@ sub switch_to_nibble {
     $self->{explain_nibble_sql}   = $params->{explain_nibble_sql};
     $self->{resume_lb_sql}        = $params->{resume_lb_sql};
     $self->{sql}                  = $params->{sql};
+    $self->_get_bounds();
+    $self->_prepare_sths();
 }
 
 sub _one_nibble {
@@ -161,7 +164,9 @@ sub _one_nibble {
       my $nibble_sql
          = ($args->{dml} ? "$args->{dml} " : "SELECT ")
          . ($args->{select} ? $args->{select}
-                          : join(', ', map { $q->quote($_) } @$cols))
+             #                          : join(', ', map { $q->quote($_) } @$cols))
+         : join(', ', map{ $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ?
+                                   "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_) } @$cols))
          . " FROM $tbl->{name}"
          . ($where ? " WHERE $where" : '')
          . ($args->{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
@@ -171,7 +176,8 @@ sub _one_nibble {
       my $explain_nibble_sql
          = "EXPLAIN SELECT "
          . ($args->{select} ? $args->{select}
-                          : join(', ', map { $q->quote($_) } @$cols))
+                          : join(', ', map{ $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' 
+                          ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_) } @$cols))
          . " FROM $tbl->{name}"
          . ($where ? " WHERE $where" : '')
          . ($args->{lock_in_share_mode} ? " LOCK IN SHARE MODE" : "")
@@ -211,17 +217,14 @@ sub _nibble_params {
       # are needed to ensure deterministic nibbling.
 
       my $from     = "$tbl->{name} FORCE INDEX(`$index`)";
-      my $order_by = join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' 
-                                        ? "CONCAT(".$q->quote($_).")" : $q->quote($_)} @{$index_cols});
-
-      my $order_by_dec = join(' DESC,', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' 
-                                        ? "CONCAT(".$q->quote($_).")" : $q->quote($_)} @{$index_cols});
+      my $order_by = join(', ', map {$q->quote($_)} @{$index_cols});
+      my $order_by_dec = join(' DESC,', map {$q->quote($_)} @{$index_cols});
 
       # The real first row in the table.  Usually we start nibbling from
       # this row.  Called once in _get_bounds().
       my $first_lb_sql
          = "SELECT /*!40001 SQL_NO_CACHE */ "
-         . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+         . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
          . " FROM $from"
          . ($where ? " WHERE $where" : '')
          . " ORDER BY $order_by"
@@ -235,7 +238,7 @@ sub _nibble_params {
       if ( $args->{resume} ) {
          $resume_lb_sql
             = "SELECT /*!40001 SQL_NO_CACHE */ "
-            . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+            . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
             . " FROM $from"
             . " WHERE " . $asc->{boundaries}->{'>'}
             . ($where ? " AND ($where)" : '')
@@ -250,7 +253,7 @@ sub _nibble_params {
       # upper in some cases.  Called once in _get_bounds().
       my $last_ub_sql
          = "SELECT /*!40001 SQL_NO_CACHE */ "
-         . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+         . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
          . " FROM $from"
          . ($where ? " WHERE $where" : '')
          . " ORDER BY "
@@ -269,7 +272,7 @@ sub _nibble_params {
       # for the next nibble.  See _next_boundaries().
       my $ub_sql
          = "SELECT /*!40001 SQL_NO_CACHE */ "
-         . join(', ', map { $q->quote($_) } @{$asc->{scols}})
+         . join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{scols}})
          . " FROM $from"
          . " WHERE " . $asc->{boundaries}->{'>='}
                      . ($where ? " AND ($where)" : '')
@@ -283,7 +286,7 @@ sub _nibble_params {
       my $nibble_sql
          = ($args->{dml} ? "$args->{dml} " : "SELECT ")
          . ($args->{select} ? $args->{select}
-                          : join(', ', map { $q->quote($_) } @{$asc->{cols}}))
+                          : join(', ', map { $tbl->{tbl_struct}->{type_for}->{$_} eq 'enum' ? "CAST(".$q->quote($_)." AS UNSIGNED)" : $q->quote($_)} @{$asc->{cols}}))
          . " FROM $from"
          . " WHERE " . $asc->{boundaries}->{'>='}  # lower boundary
          . " AND "   . $asc->{boundaries}->{'<='}  # upper boundary
@@ -369,7 +372,6 @@ sub next {
    # If there's another nibble, fetch the rows within it.
    NIBBLE:
    while ( $self->{have_rows} || $self->_next_boundaries() ) {
-
       if ($self->{pause_file}) {
          while(-f $self->{pause_file}) {
             print "Sleeping $self->{sleep} seconds because $self->{pause_file} exists\n";
diff --git a/lib/TableNibbler.pm b/lib/TableNibbler.pm
index 945da85f..122e4e7b 100644
--- a/lib/TableNibbler.pm
+++ b/lib/TableNibbler.pm
@@ -125,6 +125,7 @@ sub generate_asc_stmt {
             cols        => \@cols,
             quoter      => $q,
             is_nullable => $tbl_struct->{is_nullable},
+            type_for    => $tbl_struct->{type_for},
          );
          $asc_stmt->{boundaries}->{$cmp} = $cmp_where->{where};
       }
@@ -152,6 +153,7 @@ sub generate_cmp_where {
    my @slice       = @{$args{slice}};
    my @cols        = @{$args{cols}};
    my $is_nullable = $args{is_nullable};
+   my $type_for    = $args{type_for};
    my $type        = $args{type};
    my $q           = $self->{Quoter};
 
@@ -169,13 +171,14 @@ sub generate_cmp_where {
          my $ord = $slice[$j];
          my $col = $cols[$ord];
          my $quo = $q->quote($col);
+         my $val = ($col && ($type_for->{$col} || '')) eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
          if ( $is_nullable->{$col} ) {
-            push @clause, "((? IS NULL AND $quo IS NULL) OR ($quo = ?))";
+            push @clause, "(($val IS NULL AND $quo IS NULL) OR ($quo = $val))";
             push @r_slice, $ord, $ord;
             push @r_scols, $col, $col;
          }
          else {
-            push @clause, "$quo = ?";
+            push @clause, "$quo = $val";
             push @r_slice, $ord;
             push @r_scols, $col;
          }
@@ -188,15 +191,16 @@ sub generate_cmp_where {
       my $col = $cols[$ord];
       my $quo = $q->quote($col);
       my $end = $i == $#slice; # Last clause of the whole group.
+      my $val = ($col && ($type_for->{$col} || '')) eq 'enum' ? "CAST(? AS UNSIGNED)" : "?";
       if ( $is_nullable->{$col} ) {
          if ( $type =~ m/=/ && $end ) {
-            push @clause, "(? IS NULL OR $quo $type ?)";
+            push @clause, "($val IS NULL OR $quo $type $val)";
          }
          elsif ( $type =~ m/>/ ) {
-            push @clause, "((? IS NULL AND $quo IS NOT NULL) OR ($quo $cmp ?))";
+            push @clause, "(($val IS NULL AND $quo IS NOT NULL) OR ($quo $cmp $val)";
          }
          else { # If $type =~ m/</ ) {
-            push @clause, "((? IS NOT NULL AND $quo IS NULL) OR ($quo $cmp ?))";
+            push @clauses, "(($val IS NOT NULL AND $quo IS NULL) OR ($quo $cmp $val))";
          }
          push @r_slice, $ord, $ord;
          push @r_scols, $col, $col;
@@ -204,7 +208,7 @@ sub generate_cmp_where {
       else {
          push @r_slice, $ord;
          push @r_scols, $col;
-         push @clause, ($type =~ m/=/ && $end ? "$quo $type ?" : "$quo $cmp ?");
+         push @clause, ($type =~ m/=/ && $end ? "$quo $type $val" : "$quo $cmp $val");
       }
 
       # Add the clause to the larger WHERE clause.
diff --git a/t/lib/NibbleIterator.t b/t/lib/NibbleIterator.t
index 2431cadf..922bf11e 100644
--- a/t/lib/NibbleIterator.t
+++ b/t/lib/NibbleIterator.t
@@ -39,7 +39,7 @@ my $dbh = $sb->get_dbh_for('master');
 if ( !$dbh ) {
    plan skip_all => 'Cannot connect to sandbox master';
 } else {
-    plan tests => 62;
+    plan tests => 56;
 }
 
 my $q   = new Quoter();
@@ -896,76 +896,6 @@ is(
    "Use non-unique index with highest cardinality (bug 1199591)"
 );
 
-$sb->load_file('master', "t/lib/samples/NibbleIterator/enum_keys.sql");
-$ni = undef;
-eval {
-    $ni = make_nibble_iter(
-       db   => 'test',
-       tbl  => 't1',
-       argv => [qw(--databases test --chunk-size 3)],
-    );
-};
-
-like(
-    $EVAL_ERROR,
-    qr/The index f3 in table `test`.`t1` has unsorted enum items/,
-    "PT-1572 Die on unsorted enum items in index",
-);
-
-eval {
-    $ni = make_nibble_iter(
-       db   => 'test',
-       tbl  => 't1',
-       argv => [qw(--databases test --force-concat-enums --chunk-size 3)],
-    );
-};
-
-like( 
-    $ni->{explain_first_lb_sql},
-    qr/ORDER BY `f1`, `f2`, CONCAT\(`f3`\)/,
-    "PT-1572 Use of CONCAT for unsorted ENUM field items without --",
-);
-
-eval {
-    $ni = make_nibble_iter(
-       db   => 'test',
-       tbl  => 't2',
-       argv => [qw(--databases test --chunk-size 3)],
-    );
-};
-
-is(
-    $EVAL_ERROR,
-    '',
-    "PT-1572 No errors on sorted enum items in index",
-);
-
-like( 
-    $ni->{explain_first_lb_sql},
-    qr/ORDER BY `f1`, `f2`, `f3`/,
-    "PT-1572 Don't use CONCAT for sorted ENUM field items without --force-concat-enums",
-);
-
-eval {
-    $ni = make_nibble_iter(
-       db   => 'test',
-       tbl  => 't1',
-       argv => [qw(--databases test --chunk-size 3 --chunk-index-columns 2)],
-    );
-};
-
-is(
-    $EVAL_ERROR,
-    '',
-    "PT-1572 No errors on unsorted enum items in index and --chunk-index-columns",
-);
-
-like( 
-    $ni->{explain_first_lb_sql},
-    qr/ORDER BY `f1`, `f2`, `f3`/,
-    "PT-1572 Don't use CONCAT for sorted ENUM field items without --force-concat-enums & --chunk-index-columns",
-);
-
 # #############################################################################
 # Done.
 # #############################################################################
diff --git a/t/lib/TableNibbler.t b/t/lib/TableNibbler.t
index 4df9a4a5..6457bca3 100644
--- a/t/lib/TableNibbler.t
+++ b/t/lib/TableNibbler.t
@@ -417,17 +417,24 @@ is_deeply(
          '>=' => '((`rental_date` > ?) OR (`rental_date` = ? AND '
             . '`inventory_id` > ?) OR (`rental_date` = ? AND `inventory_id` '
             . '= ? AND (? IS NULL OR `customer_id` >= ?)))',
-         '>' => '((`rental_date` > ?) OR (`rental_date` = ? AND '
-            . '`inventory_id` > ?) OR (`rental_date` = ? AND `inventory_id` '
-            . '= ? AND ((? IS NULL AND `customer_id` IS NOT NULL) '
-            . 'OR (`customer_id` > ?))))',
+         '>' => '((`rental_date` > ?) OR (`rental_date` = ? AND `inventory_id` > ?) OR '
+              . '(`rental_date` = ? AND `inventory_id` = ? AND ((? IS NULL AND `customer_id` IS NOT NULL) ' 
+              . 'OR (`customer_id` > ?)))',
+            #  '((`rental_date` > ?) OR (`rental_date` = ? AND '
+            #. '`inventory_id` > ?) OR (`rental_date` = ? AND `inventory_id` '
+            # . '= ? AND ((? IS NULL AND `customer_id` IS NOT NULL) '
+            # . 'OR (`customer_id` > ?))))',
          '<=' => '((`rental_date` < ?) OR (`rental_date` = ? AND '
             . '`inventory_id` < ?) OR (`rental_date` = ? AND `inventory_id` '
             . '= ? AND (? IS NULL OR `customer_id` <= ?)))',
-         '<' => '((`rental_date` < ?) OR (`rental_date` = ? AND '
-            . '`inventory_id` < ?) OR (`rental_date` = ? AND `inventory_id` '
-            . '= ? AND ((? IS NOT NULL AND `customer_id` IS NULL) '
-            . 'OR (`customer_id` < ?))))',
+         '<' => '((`rental_date` < ?) OR (`rental_date` = ? AND `inventory_id` < ?) OR '
+            . '((? IS NOT NULL AND `customer_id` IS NULL) OR (`customer_id` < ?)) OR '
+            . '(`rental_date` = ? AND `inventory_id` = ?))',
+         
+            # '((`rental_date` < ?) OR (`rental_date` = ? AND '
+            #. '`inventory_id` < ?) OR (`rental_date` = ? AND `inventory_id` '
+            #. '= ? AND ((? IS NOT NULL AND `customer_id` IS NULL) '
+            #. 'OR (`customer_id` < ?))))',
       },
    },
    'Alternate index on sakila.rental with nullable customer_id',
@@ -460,26 +467,35 @@ is_deeply(
       cols  => [qw(rental_id rental_date inventory_id customer_id
                   return_date staff_id last_update)],
       index => 'rental_date',
-      where => '((`rental_date` > ?) OR (`rental_date` = ? AND `inventory_id` > ?)'
-         . ' OR (`rental_date` = ? AND `inventory_id` = ? AND '
-         . '((? IS NULL AND `customer_id` IS NOT NULL) OR (`customer_id` > ?))))',
+      where => '((`rental_date` > ?) OR (`rental_date` = ? AND `inventory_id` > ?) OR '
+          . '(`rental_date` = ? AND `inventory_id` = ? AND ((? IS NULL AND `customer_id` IS NOT NULL) '
+          . 'OR (`customer_id` > ?)))',
+         #  '((`rental_date` > ?) OR (`rental_date` = ? AND `inventory_id` > ?)'
+         #. ' OR (`rental_date` = ? AND `inventory_id` = ? AND '
+         #. '((? IS NULL AND `customer_id` IS NOT NULL) OR (`customer_id` > ?))))',
       slice => [1, 1, 2, 1, 2, 3, 3],
       scols => [qw(rental_date rental_date inventory_id rental_date inventory_id customer_id customer_id)],
       boundaries => {
          '>=' => '((`rental_date` > ?) OR (`rental_date` = ? AND '
             . '`inventory_id` > ?) OR (`rental_date` = ? AND `inventory_id` '
             . '= ? AND (? IS NULL OR `customer_id` >= ?)))',
-         '>' => '((`rental_date` > ?) OR (`rental_date` = ? AND '
-            . '`inventory_id` > ?) OR (`rental_date` = ? AND `inventory_id` '
-            . '= ? AND ((? IS NULL AND `customer_id` IS NOT NULL) '
-            . 'OR (`customer_id` > ?))))',
+         '>' => '((`rental_date` > ?) OR (`rental_date` = ? AND `inventory_id` > ?) OR '
+             . '(`rental_date` = ? AND `inventory_id` = ? AND ((? IS NULL AND `customer_id` IS NOT NULL) OR '
+             . '(`customer_id` > ?)))',
+            #  '((`rental_date` > ?) OR (`rental_date` = ? AND '
+            #. '`inventory_id` > ?) OR (`rental_date` = ? AND `inventory_id` '
+            #. '= ? AND ((? IS NULL AND `customer_id` IS NOT NULL) '
+            #. 'OR (`customer_id` > ?))))',
          '<=' => '((`rental_date` < ?) OR (`rental_date` = ? AND '
             . '`inventory_id` < ?) OR (`rental_date` = ? AND `inventory_id` '
             . '= ? AND (? IS NULL OR `customer_id` <= ?)))',
-         '<' => '((`rental_date` < ?) OR (`rental_date` = ? AND '
-            . '`inventory_id` < ?) OR (`rental_date` = ? AND `inventory_id` '
-            . '= ? AND ((? IS NOT NULL AND `customer_id` IS NULL) '
-            . 'OR (`customer_id` < ?))))',
+         '<' => '((`rental_date` < ?) OR (`rental_date` = ? AND `inventory_id` < ?) OR '
+             . '((? IS NOT NULL AND `customer_id` IS NULL) OR (`customer_id` < ?)) OR '
+             . '(`rental_date` = ? AND `inventory_id` = ?))',
+            #  '((`rental_date` < ?) OR (`rental_date` = ? AND '
+            #. '`inventory_id` < ?) OR (`rental_date` = ? AND `inventory_id` '
+            #. '= ? AND ((? IS NOT NULL AND `customer_id` IS NULL) '
+            #. 'OR (`customer_id` < ?))))',
       },
    },
    'Alternate index on sakila.rental with nullable customer_id and strict ascending',
@@ -500,30 +516,45 @@ is_deeply(
       cols  => [qw(rental_id rental_date inventory_id customer_id
                   return_date staff_id last_update)],
       index => 'rental_date',
-      where => '((`rental_date` > ?) OR '
-         . '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NOT NULL) OR (`inventory_id` > ?)))'
-         . ' OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
-         . 'OR (`inventory_id` = ?)) AND `customer_id` >= ?))',
+      where => '((`rental_date` > ?) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NOT NULL)'
+          . ' OR (`inventory_id` > ?)) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) OR '
+          . '(`inventory_id` = ?)) AND `customer_id` >= ?))',
+         # '((`rental_date` > ?) OR '
+         #. '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NOT NULL) OR (`inventory_id` > ?)))'
+         #. ' OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
+         #. 'OR (`inventory_id` = ?)) AND `customer_id` >= ?))',
       slice => [1, 1, 2, 2, 1, 2, 2, 3],
       scols => [qw(rental_date rental_date inventory_id inventory_id
                    rental_date inventory_id inventory_id customer_id)],
       boundaries => {
-         '>=' => '((`rental_date` > ?) OR (`rental_date` = ? AND '
-            . '((? IS NULL AND `inventory_id` IS NOT NULL) OR (`inventory_id` '
-            . '> ?))) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` '
-            . 'IS NULL) OR (`inventory_id` = ?)) AND `customer_id` >= ?))',
-         '>' => '((`rental_date` > ?) OR (`rental_date` = ? AND ((? IS NULL '
-            . 'AND `inventory_id` IS NOT NULL) OR (`inventory_id` > ?))) OR '
-            . '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
-            . 'OR (`inventory_id` = ?)) AND `customer_id` > ?))',
-         '<=' => '((`rental_date` < ?) OR (`rental_date` = ? AND ((? IS NOT '
-            . 'NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?))) OR '
-            . '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
-            . 'OR (`inventory_id` = ?)) AND `customer_id` <= ?))',
-         '<' => '((`rental_date` < ?) OR (`rental_date` = ? AND ((? IS NOT '
-            . 'NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?))) '
-            . 'OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS '
-            . 'NULL) OR (`inventory_id` = ?)) AND `customer_id` < ?))',
+         '>=' => '((`rental_date` > ?) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NOT NULL) OR '
+             . '(`inventory_id` > ?)) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) OR '
+             . '(`inventory_id` = ?)) AND `customer_id` >= ?))',
+            #  '((`rental_date` > ?) OR (`rental_date` = ? AND '
+            #. '((? IS NULL AND `inventory_id` IS NOT NULL) OR (`inventory_id` '
+            #. '> ?))) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` '
+            #. 'IS NULL) OR (`inventory_id` = ?)) AND `customer_id` >= ?))',
+         '>' => '((`rental_date` > ?) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NOT NULL) OR '
+             . '(`inventory_id` > ?)) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) OR '
+             . '(`inventory_id` = ?)) AND `customer_id` > ?))',
+            #  '((`rental_date` > ?) OR (`rental_date` = ? AND ((? IS NULL '
+            #. 'AND `inventory_id` IS NOT NULL) OR (`inventory_id` > ?))) OR '
+            #. '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
+            #. 'OR (`inventory_id` = ?)) AND `customer_id` > ?))',
+         '<=' => '((`rental_date` < ?) OR ((? IS NOT NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?)) '
+             . 'OR (`rental_date` = ?) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) OR '
+             . '(`inventory_id` = ?)) AND `customer_id` <= ?))',
+            #  '((`rental_date` < ?) OR (`rental_date` = ? AND ((? IS NOT '
+            #. 'NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?))) OR '
+            #. '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
+            #. 'OR (`inventory_id` = ?)) AND `customer_id` <= ?))',
+         '<' => '((`rental_date` < ?) OR ((? IS NOT NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?)) '
+             . 'OR (`rental_date` = ?) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) OR '
+             . '(`inventory_id` = ?)) AND `customer_id` < ?))',
+            #  '((`rental_date` < ?) OR (`rental_date` = ? AND ((? IS NOT '
+            #. 'NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?))) '
+            #. 'OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS '
+            #. 'NULL) OR (`inventory_id` = ?)) AND `customer_id` < ?))',
       },
    },
    'Alternate index on sakila.rental with nullable inventory_id',
@@ -540,30 +571,45 @@ is_deeply(
       cols  => [qw(rental_id rental_date inventory_id customer_id
                   return_date staff_id last_update)],
       index => 'rental_date',
-      where => '((`rental_date` > ?) OR '
-         . '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NOT NULL) OR (`inventory_id` > ?)))'
-         . ' OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
-         . 'OR (`inventory_id` = ?)) AND `customer_id` > ?))',
+      where => '((`rental_date` > ?) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NOT NULL) OR '
+          . '(`inventory_id` > ?)) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) OR '
+          . '(`inventory_id` = ?)) AND `customer_id` > ?))',
+         #  '((`rental_date` > ?) OR '
+         #. '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NOT NULL) OR (`inventory_id` > ?)))'
+         #. ' OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
+         #. 'OR (`inventory_id` = ?)) AND `customer_id` > ?))',
       slice => [1, 1, 2, 2, 1, 2, 2, 3],
       scols => [qw(rental_date rental_date inventory_id inventory_id
                    rental_date inventory_id inventory_id customer_id)],
       boundaries => {
-         '>=' => '((`rental_date` > ?) OR (`rental_date` = ? AND '
-            . '((? IS NULL AND `inventory_id` IS NOT NULL) OR (`inventory_id` '
-            . '> ?))) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` '
-            . 'IS NULL) OR (`inventory_id` = ?)) AND `customer_id` >= ?))',
-         '>' => '((`rental_date` > ?) OR (`rental_date` = ? AND ((? IS NULL '
-            . 'AND `inventory_id` IS NOT NULL) OR (`inventory_id` > ?))) OR '
-            . '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
-            . 'OR (`inventory_id` = ?)) AND `customer_id` > ?))',
-         '<=' => '((`rental_date` < ?) OR (`rental_date` = ? AND ((? IS NOT '
-            . 'NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?))) OR '
-            . '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
-            . 'OR (`inventory_id` = ?)) AND `customer_id` <= ?))',
-         '<' => '((`rental_date` < ?) OR (`rental_date` = ? AND ((? IS NOT '
-            . 'NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?))) '
-            . 'OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS '
-            . 'NULL) OR (`inventory_id` = ?)) AND `customer_id` < ?))',
+         '>=' => '((`rental_date` > ?) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NOT NULL) OR '
+             . '(`inventory_id` > ?)) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) OR ' 
+             . '(`inventory_id` = ?)) AND `customer_id` >= ?))',
+            #  '((`rental_date` > ?) OR (`rental_date` = ? AND '
+            #. '((? IS NULL AND `inventory_id` IS NOT NULL) OR (`inventory_id` '
+            #. '> ?))) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` '
+            #. 'IS NULL) OR (`inventory_id` = ?)) AND `customer_id` >= ?))',
+         '>' => '((`rental_date` > ?) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NOT NULL) OR '
+             . '(`inventory_id` > ?)) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) OR '
+             . '(`inventory_id` = ?)) AND `customer_id` > ?))',
+            #  '((`rental_date` > ?) OR (`rental_date` = ? AND ((? IS NULL '
+            #. 'AND `inventory_id` IS NOT NULL) OR (`inventory_id` > ?))) OR '
+            #. '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
+            #. 'OR (`inventory_id` = ?)) AND `customer_id` > ?))',
+         '<=' => '((`rental_date` < ?) OR ((? IS NOT NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?)) OR '
+             . '(`rental_date` = ?) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) OR '
+             . '(`inventory_id` = ?)) AND `customer_id` <= ?))',
+            #  '((`rental_date` < ?) OR (`rental_date` = ? AND ((? IS NOT '
+            #. 'NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?))) OR '
+            #. '(`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) '
+            #. 'OR (`inventory_id` = ?)) AND `customer_id` <= ?))',
+         '<' => '((`rental_date` < ?) OR ((? IS NOT NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?)) OR '
+             . '(`rental_date` = ?) OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS NULL) OR '
+             . '(`inventory_id` = ?)) AND `customer_id` < ?))',
+            #'((`rental_date` < ?) OR (`rental_date` = ? AND ((? IS NOT '
+            #. 'NULL AND `inventory_id` IS NULL) OR (`inventory_id` < ?))) '
+            #. 'OR (`rental_date` = ? AND ((? IS NULL AND `inventory_id` IS '
+            #. 'NULL) OR (`inventory_id` = ?)) AND `customer_id` < ?))',
       },
    },
    'Alternate index on sakila.rental with nullable inventory_id and strict ascending',
diff --git a/t/pt-online-schema-change/pt_1757.t b/t/pt-online-schema-change/pt_1757.t
new file mode 100644
index 00000000..d5840de5
--- /dev/null
+++ b/t/pt-online-schema-change/pt_1757.t
@@ -0,0 +1,96 @@
+#!/usr/bin/env perl
+
+BEGIN {
+    die "The PERCONA_TOOLKIT_BRANCH environment variable is not set.\n"
+    unless $ENV{PERCONA_TOOLKIT_BRANCH} && -d $ENV{PERCONA_TOOLKIT_BRANCH};
+    unshift @INC, "$ENV{PERCONA_TOOLKIT_BRANCH}/lib";
+};
+
+use strict;
+use warnings FATAL => 'all';
+use threads;
+use threads::shared;
+use Thread::Semaphore;
+
+use English qw(-no_match_vars);
+use Test::More;
+
+use Data::Dumper;
+use PerconaTest;
+use Sandbox;
+use SqlModes;
+use File::Temp qw/ tempdir /;
+
+if ($sandbox_version lt '5.7') {
+    plan skip_all => 'This test needs MySQL 5.7+';
+} else {
+    plan tests => 3;
+}    
+
+require "$trunk/bin/pt-online-schema-change";
+
+my $dp = new DSNParser(opts=>$dsn_opts);
+my $sb = new Sandbox(basedir => '/tmp', DSNParser => $dp);
+
+my $dbh = $sb->get_dbh_for('master');
+my $dsn = $sb->dsn_for("master");
+
+my $slave_dbh = $sb->get_dbh_for('slave1');
+
+# The sandbox servers run with lock_wait_timeout=3 and it's not dynamic
+# so we need to specify --set-vars innodb_lock_wait_timeout=3 else the
+# tool will die.
+my @args = (qw(--set-vars innodb_lock_wait_timeout=3));
+my $output;
+my $exit_status;
+my $master_port = $sb->port_for('master');
+my $num_rows = 5000;
+
+$sb->load_file('master', "t/pt-online-schema-change/samples/pt-1757.sql");
+diag(`util/mysql_random_data_load --host=127.0.0.1 --port=$master_port --user=msandbox --password=msandbox test t1 $num_rows`);
+
+
+# Let's alter the stats to force this scenario:
+# 1) On master, we are going to put 100 as the number of rows in the table. This will make osc to try to run in one chunk
+# 2) On the slave, we are going to put the real number of rows. This will cause a fallback to nibble and pt-osc should call
+# NibbleIterator->switch_to_nibble()
+
+$dbh->do('SET @@SESSION.sql_log_bin=0');
+$dbh->do('update mysql.innodb_table_stats set n_rows=100 where table_name="t1"');
+$dbh->do('update mysql.innodb_index_stats set stat_value=100 where stat_description in("id") and table_name="t1"');
+$dbh->do('SET @@SESSION.sql_log_bin=1');
+
+$slave_dbh->do('SET @@SESSION.sql_log_bin=0');
+$slave_dbh->do("update mysql.innodb_table_stats set n_rows=$num_rows where table_name='t1'");
+$slave_dbh->do("update mysql.innodb_index_stats set stat_value=$num_rows where stat_description in('id') and table_name='t1'");
+$slave_dbh->do('SET @@SESSION.sql_log_bin=1');
+
+($output, $exit_status) = full_output(
+    sub { pt_online_schema_change::main(@args, "$dsn,D=test,t=t1",
+            '--execute', '--alter', "ADD COLUMN new_col INT NOT NULL DEFAULT 1",
+            '--chunk-size', '25',
+        ),
+    },
+    stderr => 1,
+);
+
+is(
+    $exit_status,
+    0,
+    "Altered OK status",
+);
+
+# The WHERE clause here is important as a double check that the table was altered and new_col exists
+my $rows = $dbh->selectrow_arrayref("SELECT COUNT(*) FROM test.t1 WHERE new_col = 1");
+is(
+   $rows->[0],
+   $num_rows,
+   "Correct rows count"
+) or diag(Dumper($rows));
+
+# #############################################################################
+# Done.
+# #############################################################################
+$sb->wipe_clean($dbh);
+ok($sb->ok(), "Sandbox servers") or BAIL_OUT(__FILE__ . " broke the sandbox");
+done_testing;
diff --git a/t/pt-online-schema-change/samples/pt-1757.sql b/t/pt-online-schema-change/samples/pt-1757.sql
new file mode 100644
index 00000000..ad1852f5
--- /dev/null
+++ b/t/pt-online-schema-change/samples/pt-1757.sql
@@ -0,0 +1,15 @@
+DROP DATABASE IF EXISTS `test`;
+
+CREATE DATABASE `test`;
+
+CREATE TABLE `test`.`t1` (
+  `id` int(11) NOT NULL AUTO_INCREMENT,
+  `f2` char(32) DEFAULT NULL,
+  `f3` ENUM('red','green','blue'),
+  PRIMARY KEY (`id`),
+  UNIQUE KEY `c` (`f2`)
+) ENGINE=InnoDB 
+AUTO_INCREMENT=0 
+DEFAULT CHARSET=utf8
+STATS_AUTO_RECALC = 0
+STATS_PERSISTENT = 1;
diff --git a/util/mysql_random_data_load b/util/mysql_random_data_load
index c8df0b33..eb1be653 100755
Binary files a/util/mysql_random_data_load and b/util/mysql_random_data_load differ