当master down掉后，pt-heartbeat不断重试会导致…

root       1505   1471  0 19:13 pts/0    00:00:08 perl /usr/local/bin/pt-heartbeat --update -h 192.168.244.10 -u monitor -p monitor123 -D test --create-table
root       1563   1545  2 19:50 pts/3    00:00:00 grep pt-heartbeat

my $tries = 2;
   while ( !$dbh && $tries-- ) {
      PTDEBUG && _d($cxn_string, ' ', $user, ' ', $pass,
         join(', ', map { "$_=>$defaults->{$_}" } keys %$defaults ));

      $dbh = eval { DBI->connect($cxn_string, $user, $pass, $defaults) };

      if ( !$dbh && $EVAL_ERROR ) {
         if ( $EVAL_ERROR =~ m/locate DBD\/mysql/i ) {
            die "Cannot connect to MySQL because the Perl DBD::mysql module is "
               . "not installed or not found.  Run 'perl -MDBD::mysql' to see "
               . "the directories that Perl searches for DBD::mysql.  If "
               . "DBD::mysql is not installed, try:\n"
               . "  Debian/Ubuntu  apt-get install libdbd-mysql-perl\n"
               . "  RHEL/CentOS    yum install perl-DBD-MySQL\n"
               . "  OpenSolaris    pgk install pkg:/SUNWapu13dbd-mysql\n";
         }
         elsif ( $EVAL_ERROR =~ m/not a compiled character set|character set utf8/ ) {
            PTDEBUG && _d('Going to try again without utf8 support');
            delete $defaults->{mysql_enable_utf8};
         }
         if ( !$tries ) {
            die $EVAL_ERROR;
         }
      }
   }

PTDEBUG && _d($tries);
if ( !$tries ) {
    PTDEBUG && _d("$EVAL_ERROR"); 
    die $EVAL_ERROR; }

if ( !$tries ) {
            die "test:$EVAL_ERROR";
         }