dau_driver.stream_codec¶

Attributes¶

`_ALIGNMENT_BYTES`
`_SCALAR_RESULT_STRUCTS`
`_STRUCT_CODES`
`_ARROW_TYPE_FACTORIES`

Classes¶

`DecodedStreamColumn`
`DecodedStreamResult`
`RecordBatchColumn`	One fixed-width, null-free input column for record-batch encoding.
`DecodedRecordBatch`
`StreamEncoder`
`StreamDecoder`

Functions¶

`_arrow_to_logical_type`(arrow_type) → dau_core.stream.LogicalType
`_logical_to_arrow_type`(logical_type)
`_validate_header`(header, encoded_length) → None
`_validate_column`(header, column, encoded_length) → None
`_validate_operations`(header, operations) → None
`_validate_payload_window`(payload_offset, ...) → None
`_normalize_supported_type`(logical_type) → dau_core.stream.LogicalType
`_normalize_operation_descriptor`(operation, *[, ...]) → dau_core.stream.OperationDescriptor
`_unpack_column`(data) → dau_core.stream.ColumnDescriptor
`_unpack_operation`(data) → dau_core.stream.OperationDescriptor
`_align_up`(value, alignment) → int

Module Contents¶

dau_driver.stream_codec._ALIGNMENT_BYTES = 64¶

dau_driver.stream_codec._SCALAR_RESULT_STRUCTS¶

dau_driver.stream_codec._STRUCT_CODES¶

dau_driver.stream_codec._arrow_to_logical_type(arrow_type) → dau_core.stream.LogicalType[source]¶

dau_driver.stream_codec._logical_to_arrow_type(logical_type: dau_core.stream.LogicalType)[source]¶

dau_driver.stream_codec._ARROW_TYPE_FACTORIES¶

class dau_driver.stream_codec.DecodedStreamColumn[source]¶

header: dau_core.stream.BatchHeader¶

column: dau_core.stream.ColumnDescriptor¶

payload: bytes¶

operations: tuple[dau_core.stream.OperationDescriptor, ...] = ()¶

class dau_driver.stream_codec.DecodedStreamResult[source]¶

header: dau_core.stream.BatchHeader¶

column: dau_core.stream.ColumnDescriptor¶

payload: bytes¶

value: int | float¶

class dau_driver.stream_codec.RecordBatchColumn[source]¶

One fixed-width, null-free input column for record-batch encoding.

field_id: int¶

logical_type: dau_core.stream.LogicalType¶

payload: bytes¶

class dau_driver.stream_codec.DecodedRecordBatch[source]¶

header: dau_core.stream.BatchHeader¶

columns: tuple[dau_core.stream.ColumnDescriptor, ...]¶

payloads: tuple[bytes, ...]¶

operations: tuple[dau_core.stream.OperationDescriptor, ...] = ()¶

column_payload(field_id: int) → bytes[source]¶

class dau_driver.stream_codec.StreamEncoder[source]¶

static encode_column(logical_type: dau_core.stream.LogicalType, payload: bytes, *, row_count: int, field_id: int = 0, schema_hash: int = 0, batch_id: int = 0, operations: collections.abc.Iterable[dau_core.stream.OperationDescriptor] = ()) → bytes[source]¶

static encode_record_batch(columns: collections.abc.Sequence[RecordBatchColumn], *, row_count: int, schema_hash: int = 0, batch_id: int = 0, operations: collections.abc.Iterable[dau_core.stream.OperationDescriptor] = (), limits: dau_core.stream.RecordBatchLimits = DEFAULT_RECORD_BATCH_LIMITS) → bytes[source]¶: Encode N fixed-width, null-free columns as one multi-column batch.

static encode_arrow_batch(batch, *, schema_hash: int = 0, batch_id: int = 0, operations: collections.abc.Iterable[dau_core.stream.OperationDescriptor] = (), limits: dau_core.stream.RecordBatchLimits = DEFAULT_RECORD_BATCH_LIMITS) → bytes[source]¶: Encode a PyArrow RecordBatch/Table of fixed-width, null-free columns.

class dau_driver.stream_codec.StreamDecoder[source]¶

static decode_column(data: bytes) → DecodedStreamColumn[source]¶

static decode_record_batch(data: bytes, *, limits: dau_core.stream.RecordBatchLimits = DEFAULT_RECORD_BATCH_LIMITS) → DecodedRecordBatch[source]¶: Decode a multi-column record batch (the N-column counterpart of decode_column).

static decode_record_batch_to_arrow(data: bytes, *, names: collections.abc.Sequence[str] | None = None, limits: dau_core.stream.RecordBatchLimits = DEFAULT_RECORD_BATCH_LIMITS)[source]¶: Decode and rematerialize as a PyArrow RecordBatch.

static decode_scalar_result(data: bytes) → DecodedStreamResult[source]¶

dau_driver.stream_codec._validate_header(header: dau_core.stream.BatchHeader, encoded_length: int) → None[source]¶

dau_driver.stream_codec._validate_column(header: dau_core.stream.BatchHeader, column: dau_core.stream.ColumnDescriptor, encoded_length: int) → None[source]¶

dau_driver.stream_codec._validate_operations(header: dau_core.stream.BatchHeader, operations: tuple[dau_core.stream.OperationDescriptor, ...]) → None[source]¶

dau_driver.stream_codec._validate_payload_window(payload_offset: int, payload_length: int, encoded_length: int) → None[source]¶

dau_driver.stream_codec._normalize_supported_type(logical_type: dau_core.stream.LogicalType) → dau_core.stream.LogicalType[source]¶

dau_driver.stream_codec._normalize_operation_descriptor(operation: dau_core.stream.OperationDescriptor, *, column_count: int = 1) → dau_core.stream.OperationDescriptor[source]¶

dau_driver.stream_codec._unpack_column(data: bytes) → dau_core.stream.ColumnDescriptor[source]¶

dau_driver.stream_codec._unpack_operation(data: bytes) → dau_core.stream.OperationDescriptor[source]¶

dau_driver.stream_codec._align_up(value: int, alignment: int) → int[source]¶