Parquet Import

Import existing Parquet files directly into Arc. Useful for data lake integration, analytics pipeline output, or migrating from other columnar stores.

Available since v26.02.1

Parquet bulk import is available starting Arc v26.02.1 (February 2026).

Changed in v26.06.2

Parquet import now reads the file in-process (via Apache Arrow) instead of through DuckDB. The request and response are unchanged. Two things to be aware of: DECIMAL columns are imported as DOUBLE, and empty files / duplicate column names / a time_column rename that collides with an existing time column are rejected with 400.

Endpoint

POST /api/v1/import/parquet

Headers

Header	Required	Default	Description
Authorization	Yes	-	Bearer $ARC_TOKEN
X-Arc-Database	Yes	-	Target database name (or use db query param)

Query Parameters

Parameter	Required	Default	Description
measurement	Yes	-	Target measurement name
time_column	No	time	Name of the timestamp column in the Parquet file

Example

curl -X POST "http://localhost:8000/api/v1/import/parquet?measurement=metrics" \
  -H "Authorization: Bearer $ARC_TOKEN" \
  -H "X-Arc-Database: production" \
  -F "file=@data_export.parquet"

Response

{
  "status": "ok",
  "result": {
    "database": "production",
    "measurement": "metrics",
    "rows_imported": 1200000,
    "partitions_created": 8,
    "time_range_min": "2026-01-01T00:00:00Z",
    "time_range_max": "2026-01-01T07:45:00Z",
    "columns": ["time", "host", "region", "cpu_usage", "mem_usage"],
    "duration_ms": 890
  }
}

Notes

• The Parquet file must contain a timestamp column (default name: time). Use the time_column parameter if your column has a different name. The time column may be an Arrow TIMESTAMP (any unit), an integer epoch column (any width), a floating-point epoch column (use time_format, or auto-detect by magnitude), or a timestamp string column.
• Arc reads the Parquet file in-process via Apache Arrow and repartitions the data into Arc's hourly partition layout regardless of the source file's structure. Supported column types: integer (all widths, signed and unsigned), floating point, boolean, string, binary/byte-array, decimal (imported as DOUBLE), and timestamp.
• DECIMAL columns are imported as DOUBLE. If you need exact decimal precision, use Line Protocol ingestion with a configured decimal column.
• Maximum file size: 500 MB.
• RBAC: write permissions are checked for the target measurement.

Error Responses

Status	Description
400	Missing database/measurement/file; empty file or no rows; time_column not found; empty or duplicate column names; a time_column rename that collides with an existing time column; or a NaN/Inf value in a floating-point time column
403	Insufficient write permissions
413	File exceeds 500 MB size limit
422	Unreadable Parquet file, or an unsupported column type
500	Import execution error