Update all modules in pt-table-checksum.

bin/pt-table-checksum

@@ -2208,8 +2208,12 @@ sub generate_asc_stmt {
 
    my @asc_cols = @{$tbl_struct->{keys}->{$index}->{cols}};
    if ( $args{asc_first} ) {
-      @asc_cols = $asc_cols[0];
       PTDEBUG && _d('Ascending only first column');
+      @asc_cols = $asc_cols[0];
+   }
+   elsif ( my $n = $args{n_index_cols} ) {
+      PTDEBUG && _d('Ascending only first', $n, 'columns');
+      @asc_cols = @asc_cols[0..($n-1)];
    }
    PTDEBUG && _d('Will ascend columns', join(', ', @asc_cols));
 
@@ -3594,10 +3598,11 @@ sub new {
 
       my $asc = $args{TableNibbler}->generate_asc_stmt(
          %args,
-         tbl_struct => $tbl->{tbl_struct},
-         index      => $index,
-         cols       => \@cols,
-         asc_only   => 1,
+         tbl_struct   => $tbl->{tbl_struct},
+         index        => $index,
+         n_index_cols => $args{n_chunk_index_cols},
+         cols         => \@cols,
+         asc_only     => 1,
       );
       PTDEBUG && _d('Ascend params:', Dumper($asc));
 
@@ -5116,6 +5121,7 @@ use constant PTDEBUG => $ENV{PTDEBUG} || 0;
 
 use Time::Local qw(timegm timelocal);
 use Digest::MD5 qw(md5_hex);
+use B qw();
 
 require Exporter;
 our @ISA         = qw(Exporter);
@@ -5133,6 +5139,7 @@ our @EXPORT_OK   = qw(
    any_unix_timestamp
    make_checksum
    crc32
+   encode_json
 );
 
 our $mysql_ts  = qr/(\d\d)(\d\d)(\d\d) +(\d+):(\d+):(\d+)(\.\d+)?/;
@@ -5340,6 +5347,96 @@ sub crc32 {
    return $crc ^ 0xFFFFFFFF;
 }
 
+my $got_json = eval { require JSON };
+sub encode_json {
+   return JSON::encode_json(@_) if $got_json;
+   my ( $data ) = @_;
+   return (object_to_json($data) || '');
+}
+
+
+sub object_to_json {
+   my ($obj) = @_;
+   my $type  = ref($obj);
+
+   if($type eq 'HASH'){
+      return hash_to_json($obj);
+   }
+   elsif($type eq 'ARRAY'){
+      return array_to_json($obj);
+   }
+   else {
+      return value_to_json($obj);
+   }
+}
+
+sub hash_to_json {
+   my ($obj) = @_;
+   my @res;
+   for my $k ( sort { $a cmp $b } keys %$obj ) {
+      push @res, string_to_json( $k )
+         .  ":"
+         . ( object_to_json( $obj->{$k} ) || value_to_json( $obj->{$k} ) );
+   }
+   return '{' . ( @res ? join( ",", @res ) : '' )  . '}';
+}
+
+sub array_to_json {
+   my ($obj) = @_;
+   my @res;
+
+   for my $v (@$obj) {
+      push @res, object_to_json($v) || value_to_json($v);
+   }
+
+   return '[' . ( @res ? join( ",", @res ) : '' ) . ']';
+}
+
+sub value_to_json {
+   my ($value) = @_;
+
+   return 'null' if(!defined $value);
+
+   my $b_obj = B::svref_2object(\$value);  # for round trip problem
+   my $flags = $b_obj->FLAGS;
+   return $value # as is 
+      if $flags & ( B::SVp_IOK | B::SVp_NOK ) and !( $flags & B::SVp_POK ); # SvTYPE is IV or NV?
+
+   my $type = ref($value);
+
+   if( !$type ) {
+      return string_to_json($value);
+   }
+   else {
+      return 'null';
+   }
+
+}
+
+my %esc = (
+   "\n" => '\n',
+   "\r" => '\r',
+   "\t" => '\t',
+   "\f" => '\f',
+   "\b" => '\b',
+   "\"" => '\"',
+   "\\" => '\\\\',
+   "\'" => '\\\'',
+);
+
+sub string_to_json {
+   my ($arg) = @_;
+
+   $arg =~ s/([\x22\x5c\n\r\t\f\b])/$esc{$1}/g;
+   $arg =~ s/\//\\\//g;
+   $arg =~ s/([\x00-\x08\x0b\x0e-\x1f])/'\\u00' . unpack('H2', $1)/eg;
+
+   utf8::upgrade($arg);
+   utf8::encode($arg);
+
+   return '"' . $arg . '"';
+}
+
 sub _d {
    my ($package, undef, $line) = caller 0;
    @_ = map { (my $temp = $_) =~ s/\n/\n# /g; $temp; }