class DuckDB::ArrowArrayStream

The ArrowArrayStream class represents an exported Arrow C stream of a query result (Arrow C Data Interface). It is created by DuckDB::Result#arrow_c_stream and cannot be instantiated directly.

The object satisfies the Ruby Arrow C stream protocol: arrow_c_stream returns self and to_i returns the address of the underlying struct ArrowArrayStream, so it can be consumed by ruby-polars, red-arrow and other Arrow consumers:

result = con.query('SELECT * FROM users')

# ruby-polars
df = Polars::DataFrame.new(result)

# red-arrow
reader = Arrow::RecordBatchReader.import(result.arrow_c_stream.to_i)

The consumer takes ownership of the stream’s contents; a result can be exported only once.

EXPERIMENTAL: This API is built on DuckDB’s unstable Arrow C API and

may change in any minor release.

Public Class Methods

new ()

Source

# File lib/duckdb/arrow_array_stream.rb, line 28
def new
  raise DuckDB::Error, 'DuckDB::ArrowArrayStream cannot be instantiated directly. Use DuckDB::Result#arrow_c_stream.'
end

Public Instance Methods

arrow_c_stream → self

Source

static VALUE arrow_array_stream_arrow_c_stream(VALUE self) {
    return self;
}

Returns self. Defined so that the stream object itself satisfies the Arrow C stream protocol used by ruby-polars and others.

to_i → Integer

Source

static VALUE arrow_array_stream_to_i(VALUE self) {
    rubyDuckDBArrowArrayStream *p;

    TypedData_Get_Struct(self, rubyDuckDBArrowArrayStream, &arrow_array_stream_data_type, p);
    return ULL2NUM((unsigned long long)(uintptr_t)&(p->stream));
}

Returns the address of the underlying C struct ArrowArrayStream. Arrow consumers such as red-arrow accept this address directly:

reader = Arrow::RecordBatchReader.import(stream.to_i)