column profile drift derived

{
  "input": {
    "body": {
      "after": "order_id,amount,status,channel\nO-1,10,open,web\nO-2,,open,web\nO-3,30,closed,app\nO-4,99999,disputed,app\n",
      "before": "order_id,amount,status,legacy_code\nO-1,10,open,L1\nO-2,20,open,L2\nO-3,30,closed,L3\nO-4,40,closed,L4\n",
      "null_rate_tolerance": 0.1,
      "cardinality_tolerance": 0.2
    },
    "type": "http",
    "method": "POST",
    "bodyType": "json"
  },
  "output": {
    "type": "json",
    "example": {
      "limits": {
        "maxRows": 5000,
        "maxListed": 200,
        "maxColumns": 64,
        "maxCsvBytes": 262144,
        "maxDatasets": 10,
        "maxFindings": 500,
        "maxCategories": 1000,
        "maxKeyColumns": 4
      },
      "passed": false,
      "stable": false,
      "columns": [
        {
          "range": {
            "after": [
              null,
              null
            ],
            "before": [
              null,
              null
            ]
          },
          "column": "order_id",
          "null_rate": {
            "after": 0,
            "before": 0
          },
          "dominant_type": {
            "after": "string",
            "before": "string"
          },
          "distinct_count": {
            "after": 4,
            "before": 4
          }
        },
        {
          "range": {
            "after": [
              "10",
              "99999"
            ],
            "before": [
              "10",
              "40"
            ]
          },
          "column": "amount",
          "null_rate": {
            "after": 0.25,
            "before": 0
          },
          "dominant_type": {
            "after": "integer",
            "before": "integer"
          },
          "distinct_count": {
            "after": 3,
            "before": 4
          }
        },
        {
          "range": {
            "after": [
              null,
              null
            ],
            "before": [
              null,
              null
            ]
          },
          "column": "status",
          "null_rate": {
            "after": 0,
            "before": 0
          },
          "dominant_type": {
            "after": "string",
            "before": "string"
          },
          "distinct_count": {
            "after": 3,
            "before": 2
          }
        }
      ],
      "complete": true,
      "findings": [
        {
          "code": "COLUMN_REMOVED",
          "column": "legacy_code",
          "detail": "legacy_code is in the earlier dataset and gone from the later one."
        },
        {
          "code": "COLUMN_ADDED",
          "column": "channel",
          "detail": "channel is new in the later dataset."
        },
        {
          "code": "NULL_RATE_DRIFT",
          "column": "amount",
          "detail": "amount moved from 0.00% empty to 25.00%, beyond the 10.00% tolerance."
        }
      ],
      "request_id": "example-request",
      "service_id": "column_profile_drift",
      "assumptions": [
        "Drift is measured between the two datasets supplied, not against any historical baseline.",
        "A column whose distinct values exceed the category bound on either side has its cardinality reported as not compared rather than compared against a truncated count.",
        "A range that widened is reported because it means values outside what anything downstream was built for, whatever the distribution looks like."
      ],
      "limitations": [
        "Shape and distribution of the columns supplied. Whether drift is expected is the caller’s judgement.",
        "stable is true only when both datasets were fully read and nothing drifted beyond tolerance."
      ],
      "observed_at": "2026-10-02T00:00:00.000Z",
      "not_examined": [],
      "added_columns": [
        "channel"
      ],
      "finding_count": 6,
      "after_row_count": 4,
      "removed_columns": [
        "legacy_code"
      ],
      "service_version": "1.0.0",
      "before_row_count": 4,
      "findings_by_code": {
        "COLUMN_ADDED": 1,
        "COLUMN_REMOVED": 1,
        "NULL_RATE_DRIFT": 1,
        "CARDINALITY_DRIFT": 2,
        "RANGE_WIDENED_ABOVE": 1
      },
      "null_rate_tolerance": 0.1,
      "shared_column_count": 3,
      "cardinality_tolerance": 0.2
    }
  }
}