FragmentScanOptions {arrow}

Format-specific scan options

Description

A FragmentScanOptions holds options specific to a FileFormat and a scan operation.

Factory

FragmentScanOptions$create() takes the following arguments:

• format: A string identifier of the file format. Currently supported values:

  • "parquet"

  • "csv"/"text", aliases for the same format.

• ...: Additional format-specific options

  format = "parquet":

  • use_buffered_stream: Read files through buffered input streams rather than loading entire row groups at once. This may be enabled to reduce memory overhead. Disabled by default.

  • buffer_size: Size of buffered stream, if enabled. Default is 8KB.

  • pre_buffer: Pre-buffer the raw Parquet data. This can improve performance on high-latency filesystems. Disabled by default.

  • thrift_string_size_limit: Maximum string size allocated for decoding thrift strings. May need to be increased in order to read files with especially large headers. Default value 100000000.

  • thrift_container_size_limit: Maximum size of thrift containers. May need to be increased in order to read files with especially large headers. Default value 1000000. format = "text": see CsvConvertOptions. Note that options can only be specified with the Arrow C++ library naming. Also, "block_size" from CsvReadOptions may be given.

It returns the appropriate subclass of FragmentScanOptions (e.g. CsvFragmentScanOptions).