Module arrow_metadata 

Transport-neutral Arrow field-metadata keys, shared by both the ingress Arrow encoder (RecordBatch → Buffer) and the egress Arrow adapter (Cursor → RecordBatch). Lives here — rather than under egress::arrow — so a sender-only arrow-ingress build can reference the keys without pulling in the egress reader. This top-level module is the canonical public home for metadata used by either direction.

These keys are written into the Arc<Field> of every column the client emits, and read back by classify on ingress and by mid-stream drift detection (schemas_equal).

Constants

ARRAY_DIM

Native ARRAY dimensionality.

ARRAY_DIM_TENTATIVE

"true" when ARRAY_DIM is a placeholder from an empty batch; drift detection accepts any opposite ndim until firmed up.

ARROW_EXTENSION_NAME

Standard Apache Arrow extension-name field-metadata key.

COLUMN_TYPE

Carries the QuestDB native column type when the Arrow type alone is ambiguous (e.g. Int8 → byte, UInt16 → char).

DESIGNATED_TIMESTAMP

"true" on the field that is the table’s designated timestamp. Informational only — not load-bearing for drift detection.

DESIGNATED_TIMESTAMP_ORDER

"asc" / "desc". Informational only.

EXT_ARROW_UUID

Value used in ARROW_EXTENSION_NAME to mark a FixedSizeBinary(16) column as the canonical Arrow UUID.

GEOHASH_BITS

Geohash precision in bits (1..=60). Required when the QuestDB native column kind is geohash*.

SYMBOL

Marks a UTF-8 / dictionary column as the QuestDB SYMBOL kind.