ptars 0.0.16

Convert from protobuf to arrow and back in rust

ptars

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Fast convertion from Protocol Buffers to Arrow, and back, using Rust, with Python bindings.

Example

Take a protobuf:

message SearchRequest {
  string query = 1;
  int32 page_number = 2;
  int32 result_per_page = 3;
}

And convert serialized messages directly to pyarrow.RecordBatch:

from ptars import HandlerPool


messages = [
    SearchRequest(
        query="protobuf to arrow",
        page_number=0,
        result_per_page=10,
    ),
    SearchRequest(
        query="protobuf to arrow",
        page_number=1,
        result_per_page=10,
    ),
]
payloads = [message.SerializeToString() for message in messages]

pool = HandlerPool([SearchRequest.DESCRIPTOR.file])
handler = pool.get_for_message(SearchRequest.DESCRIPTOR)
record_batch = handler.list_to_record_batch(payloads)

query	page_number	result_per_page
protobuf to arrow	0	10
protobuf to arrow	1	10

You can also convert a pyarrow.RecordBatch back to serialized protobuf messages:

array: pa.BinaryArray = handler.record_batch_to_array(record_batch)
messages_back: list[SearchRequest] = [
    SearchRequest.FromString(s.as_py()) for s in array
]

Configuration

Customize Arrow type mappings with PtarsConfig:

from ptars import HandlerPool, PtarsConfig

config = PtarsConfig(
    timestamp_unit="us",  # microseconds instead of nanoseconds
    timestamp_tz="America/New_York",
)

pool = HandlerPool([SearchRequest.DESCRIPTOR.file], config=config)

Benchmark against protarrow

Ptars is a rust implementation of protarrow, which is implemented in plain python. It is:

• 2.5 times faster when converting from proto to arrow.
• 3 times faster when converting from arrow to proto.

---- benchmark 'to_arrow': 2 tests ----
Name (time in ms)        Mean
---------------------------------------
protarrow_to_arrow     9.4863 (2.63)
ptars_to_arrow         3.6009 (1.0)
---------------------------------------

---- benchmark 'to_proto': 2 tests -----
Name (time in ms)         Mean
----------------------------------------
protarrow_to_proto     20.8297 (3.20)
ptars_to_proto          6.5013 (1.0)
----------------------------------------