If the ping method is not available, you could try something like this:

my $sth = $dbh->prepare('SELECT * FROM dual');
my $rows = $sth->execute();
if ($rows != 1) {
   # try to reconnect
}
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Selecting from dual always retrieves a single record. Caveat: I use Oracle. I'm not sure if dual is implemented on other database engines. --Akoya