PT-1985 pt-deadlock db schema check (#502)

bin/pt-deadlock-logger

@@ -4675,6 +4675,9 @@ sub main {
          $sql =~ s/deadlocks/IF NOT EXISTS $db_tbl/;
          PTDEBUG && _d($sql);
          $dst->dbh->do($sql);
+         if ( $EVAL_ERROR ) {
+             _die("Cannot connect to MySQL: $EVAL_ERROR", 1);
+         }  
       }
    }
 

t/pt-deadlock-logger/check_schema_exists.t

@@ -0,0 +1,37 @@
+#!/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 English qw(-no_match_vars);
+use Test::More;
+
+use PerconaTest;
+use Sandbox;
+require "$trunk/bin/pt-deadlock-logger";
+
+my $dp  = new DSNParser(opts=>$dsn_opts);
+my $sb  = new Sandbox(basedir => '/tmp', DSNParser => $dp);
+my $dbh = $sb->get_dbh_for('master');
+
+my ($output, $exist_status) = full_output(
+   sub {
+      pt_deadlock_logger::main(
+         "h=127.1,D=non_existent_db,u=msandbox,p=msandbox",
+         qw(--clear-deadlocks non_existent_db.make_deadlock --port 12345),
+         qw(--iterations 1)
+      )
+   }
+);
+
+# #############################################################################
+# Done.
+# #############################################################################
+$sb->wipe_clean($dbh);
+ok($sb->ok(), "Sandbox servers") or BAIL_OUT(__FILE__ . " broke the sandbox");
+done_testing;