# If the transaction is stopped initializing the values.
        $hash{$2}->[0] = 0;
        $hash{$2}->[1] = 0;
        $hash{$2}->[2] = 0;
        $hash{$2}->[3] = 0;
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Instead of initializing to 0, delete the hash like  delete ( $hash{$2} ) which could optimize the use of memory.
Also instead of using  $hash{$2}->[1]i.e., using Array in Hash use Hash of Hash which will be more readable !!