We're reaching a point where we may need to be careful about decisions that increase code size:

• Instantiating too many templates for code that isn't performance sensitive, or where some templates may do the same thing (e.g. Int32Type kernels may do the same thing as a Date32Type kernel)

• Inlining functions that don't need to be inline

  Code size tends to correlate also with compilation times, but not always.

  I'll use this umbrella issue to organize issues related to reducing compiled code size

  At this moment (2020-05-27), here are the 25 largest object files in a -O2 build

  524896	src/arrow/CMakeFiles/arrow_objlib.dir/array/builder_dict.cc.o
  531920	src/arrow/CMakeFiles/arrow_objlib.dir/filesystem/s3fs.cc.o
  552000	src/arrow/CMakeFiles/arrow_objlib.dir/json/converter.cc.o
  575920	src/arrow/CMakeFiles/arrow_objlib.dir/csv/converter.cc.o
  595112	src/arrow/CMakeFiles/arrow_objlib.dir/compute/kernels/scalar_cast_string.cc.o
  645728	src/arrow/CMakeFiles/arrow_objlib.dir/type.cc.o
  683040	src/arrow/CMakeFiles/arrow_objlib.dir/compute/kernels/scalar_set_lookup.cc.o
  702232	src/arrow/CMakeFiles/arrow_objlib.dir/ipc/reader.cc.o
  729912	src/arrow/CMakeFiles/arrow_objlib.dir/tensor/coo_converter.cc.o
  752776	src/arrow/CMakeFiles/arrow_objlib.dir/tensor/csc_converter.cc.o
  752776	src/arrow/CMakeFiles/arrow_objlib.dir/tensor/csr_converter.cc.o
  877680	src/arrow/CMakeFiles/arrow_objlib.dir/array/dict_internal.cc.o
  885624	src/arrow/CMakeFiles/arrow_objlib.dir/builder.cc.o
  919072	src/arrow/CMakeFiles/arrow_objlib.dir/scalar.cc.o
  941776	src/arrow/CMakeFiles/arrow_objlib.dir/ipc/json_internal.cc.o
  1055248	src/arrow/CMakeFiles/arrow_objlib.dir/ipc/json_simple.cc.o
  1233304	src/arrow/CMakeFiles/arrow_objlib.dir/compute/kernels/scalar_compare.cc.o
  1265160	src/arrow/CMakeFiles/arrow_objlib.dir/sparse_tensor.cc.o
  1343480	src/arrow/CMakeFiles/arrow_objlib.dir/tensor/csf_converter.cc.o
  1346928	src/arrow/CMakeFiles/arrow_objlib.dir/array.cc.o
  1502568	src/arrow/CMakeFiles/arrow_objlib.dir/compute/kernels/vector_hash.cc.o
  1609760	src/arrow/CMakeFiles/arrow_objlib.dir/compute/kernels/scalar_cast_numeric.cc.o
  1794416	src/arrow/CMakeFiles/arrow_objlib.dir/array/diff.cc.o
  2759552	src/arrow/CMakeFiles/arrow_objlib.dir/compute/kernels/vector_filter.cc.o
  7609432	src/arrow/CMakeFiles/arrow_objlib.dir/compute/kernels/vector_take.cc.o

Reporter: Wes McKinney / @wesm
Assignee: Wes McKinney / @wesm

Related issues:

• [C++] Reducing the code size of the tensor module (relates to)
• [C++] Reduce number of take kernels (relates to)
• [C++] Reduce generated code in vector_hash.cc (relates to)
• [C++] Reduce generated code in compute/kernels/scalar_compare.cc (relates to)
• [C++] Optimize Filter implementation (relates to)
• [C++] diff.cc is extremely slow to compile (relates to)
• [C++] Refine TransferBitmap template parameters (relates to)
• [C++] BitUtil::SetBitsTo probably doesn't need to be inline (is related to)

_{Note: This issue was originally created as ARROW-8970. Please see the migration documentation for further details.}