{
  "external_effect_before_offset": {
    "after_replay": {
      "committed_group_offset": 1,
      "consumer_position": 1,
      "external_side_effect_count": 2,
      "output_high_watermark": 0,
      "output_last_stable_offset": 0,
      "read_committed_output": [],
      "read_uncommitted_output": [],
      "replicated_committed_log_position": 1,
      "transaction_state": "none"
    },
    "before_crash": {
      "committed_group_offset": 0,
      "consumer_position": 1,
      "external_side_effect_count": 1,
      "output_high_watermark": 0,
      "output_last_stable_offset": 0,
      "read_committed_output": [],
      "read_uncommitted_output": [],
      "replicated_committed_log_position": 1,
      "transaction_state": "none"
    },
    "duplicate_external_effect": true,
    "trace": [
      "external effect completed once",
      "process crashed before group offset commit",
      "restart replayed input-0 and repeated the effect"
    ]
  },
  "external_effect_outside_transaction": {
    "after_abort": {
      "committed_group_offset": 0,
      "consumer_position": 0,
      "external_side_effect_count": 1,
      "output_high_watermark": 1,
      "output_last_stable_offset": 1,
      "read_committed_output": [],
      "read_uncommitted_output": [
        "output-0"
      ],
      "replicated_committed_log_position": 1,
      "transaction_state": "aborted"
    },
    "after_replay": {
      "committed_group_offset": 0,
      "consumer_position": 1,
      "external_side_effect_count": 2,
      "output_high_watermark": 1,
      "output_last_stable_offset": 1,
      "read_committed_output": [],
      "read_uncommitted_output": [
        "output-0"
      ],
      "replicated_committed_log_position": 1,
      "transaction_state": "none"
    },
    "before_abort": {
      "committed_group_offset": 0,
      "consumer_position": 1,
      "external_side_effect_count": 1,
      "output_high_watermark": 1,
      "output_last_stable_offset": 0,
      "read_committed_output": [],
      "read_uncommitted_output": [
        "output-0"
      ],
      "replicated_committed_log_position": 1,
      "transaction_state": "ongoing"
    },
    "trace": [
      "Kafka output staged and external effect completed",
      "Kafka transaction aborted; output and offset did not commit",
      "external system did not roll back; replay repeated its effect"
    ]
  },
  "kafka_transaction": {
    "abort_path": {
      "after": {
        "committed_group_offset": 0,
        "consumer_position": 0,
        "external_side_effect_count": 0,
        "output_high_watermark": 1,
        "output_last_stable_offset": 1,
        "read_committed_output": [],
        "read_uncommitted_output": [
          "aborted-output"
        ],
        "replicated_committed_log_position": 1,
        "transaction_state": "aborted"
      },
      "before": {
        "committed_group_offset": 0,
        "consumer_position": 1,
        "external_side_effect_count": 0,
        "output_high_watermark": 1,
        "output_last_stable_offset": 0,
        "read_committed_output": [],
        "read_uncommitted_output": [
          "aborted-output"
        ],
        "replicated_committed_log_position": 1,
        "transaction_state": "ongoing"
      }
    },
    "commit_path": {
      "after": {
        "committed_group_offset": 1,
        "consumer_position": 1,
        "external_side_effect_count": 0,
        "output_high_watermark": 1,
        "output_last_stable_offset": 1,
        "read_committed_output": [
          "output-0"
        ],
        "read_uncommitted_output": [
          "output-0"
        ],
        "replicated_committed_log_position": 1,
        "transaction_state": "committed"
      },
      "before": {
        "committed_group_offset": 0,
        "consumer_position": 1,
        "external_side_effect_count": 0,
        "output_high_watermark": 1,
        "output_last_stable_offset": 0,
        "read_committed_output": [],
        "read_uncommitted_output": [
          "output-0"
        ],
        "replicated_committed_log_position": 1,
        "transaction_state": "ongoing"
      }
    }
  },
  "log_committed_offset_not_committed": {
    "after_replay": {
      "committed_group_offset": 1,
      "consumer_position": 1,
      "external_side_effect_count": 2,
      "output_high_watermark": 0,
      "output_last_stable_offset": 0,
      "read_committed_output": [],
      "read_uncommitted_output": [],
      "replicated_committed_log_position": 1,
      "transaction_state": "none"
    },
    "before_crash": {
      "committed_group_offset": 0,
      "consumer_position": 1,
      "external_side_effect_count": 1,
      "output_high_watermark": 0,
      "output_last_stable_offset": 0,
      "read_committed_output": [],
      "read_uncommitted_output": [],
      "replicated_committed_log_position": 1,
      "transaction_state": "none"
    },
    "trace": [
      "input-0 replicated and committed at input offset 0",
      "consumer processed input-0, but group offset stayed at 0",
      "restart resumed at offset 0 and repeated the effect"
    ]
  },
  "model": "deterministic Kafka commit-boundary model",
  "not_modeled": [
    "a real Kafka broker, producer, consumer, coordinator, or network",
    "ISR election, disk persistence, arbitrary interleavings, or timing",
    "throughput, latency, security, and version compatibility"
  ],
  "offset_before_external_effect": {
    "after_restart": {
      "committed_group_offset": 1,
      "consumer_position": 1,
      "external_side_effect_count": 0,
      "output_high_watermark": 0,
      "output_last_stable_offset": 0,
      "read_committed_output": [],
      "read_uncommitted_output": [],
      "replicated_committed_log_position": 1,
      "transaction_state": "none"
    },
    "before_crash": {
      "committed_group_offset": 1,
      "consumer_position": 1,
      "external_side_effect_count": 0,
      "output_high_watermark": 0,
      "output_last_stable_offset": 0,
      "read_committed_output": [],
      "read_uncommitted_output": [],
      "replicated_committed_log_position": 1,
      "transaction_state": "none"
    },
    "lost_external_effect": true,
    "trace": [
      "consumer advanced and committed group offset 1",
      "process crashed before the external effect",
      "restart resumed at offset 1; input-0 was not replayed"
    ]
  }
}