PID 20939 Forked worker in slot 2 with pid 20942 for chunk 1 Forked worker in slot 1 with pid 20941 for chunk 2 After 0: $VAR1 = { '00 20942' => '1491574178', '01 20941' => '1491574178' }; After 1: $VAR1 = { '00 20942' => '1491574178', '01 20941' => '1491574178' }; Forked worker in slot 2 with pid 20942 for chunk 3 Forked worker in slot 1 with pid 20941 for chunk 4 After 2: $VAR1 = { '00 20942' => '1491574178', '01 20941' => '1491574178', '02 20942' => '1491574179', '03 20941' => '1491574179' }; After 3: $VAR1 = { '00 20942' => '1491574178', '01 20941' => '1491574178', '02 20942' => '1491574179', '03 20941' => '1491574179' }; Forked worker in slot 2 with pid 20942 for chunk 5 After 4: $VAR1 = { '00 20942' => '1491574178', '01 20941' => '1491574178', '02 20942' => '1491574179', '03 20941' => '1491574179', '04 20942' => '1491574180' }; 20941 1491574181 (Child) in END 20942 1491574181 (Child) in END 20939 1491574181 (Parent) in END Parent is ready to dump Dumping: $VAR1 = { '00 20942' => '1491574178', '01 20941' => '1491574178', '02 20942' => '1491574179', '03 20941' => '1491574179', '04 20942' => '1491574180' };