python - Memory error while using pip install Matplotlib

Question

I am using Python 2.7, If i try to install Matplotlib I am getting this error if i use "pip install matplotlib"

 Exception:
  Traceback (most recent call last):
    File "/usr/local/lib/python2.7/dist-packages/pip/basecommand.py", line 232, in main
      status = self.run(options, args)
    File "/usr/local/lib/python2.7/dist-packages/pip/commands/install.py", line 339, in run
      requirement_set.prepare_files(finder)
    File "/usr/local/lib/python2.7/dist-packages/pip/req/req_set.py", line 355, in prepare_files
      do_download, session=self.session,
    File "/usr/local/lib/python2.7/dist-packages/pip/download.py", line 782, in unpack_url
      session,
    File "/usr/local/lib/python2.7/dist-packages/pip/download.py", line 667, in unpack_http_url
      from_path, content_type = _download_http_url(link, session, temp_dir)
    File "/usr/local/lib/python2.7/dist-packages/pip/download.py", line 843, in _download_http_url
      _download_url(resp, link, content_file)
    File "/usr/local/lib/python2.7/dist-packages/pip/download.py", line 615, in _download_url
      for chunk in progress_indicator(resp_read(4096), 4096):
    File "/usr/local/lib/python2.7/dist-packages/pip/utils/ui.py", line 46, in iter
      for x in it:
    File "/usr/local/lib/python2.7/dist-packages/pip/download.py", line 580, in resp_read
      decode_content=False):
    File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/requests/packages/urllib3/response.py", line 256, in stream
      data = self.read(amt=amt, decode_content=decode_content)
    File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/requests/packages/urllib3/response.py", line 186, in read
      data = self._fp.read(amt)
    File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/cachecontrol/filewrapper.py", line 54, in read
      self.__callback(self.__buf.getvalue())
    File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/cachecontrol/controller.py", line 205, in cache_response
      self.serializer.dumps(request, response, body=body),
    File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/cachecontrol/serialize.py", line 81, in dumps
      ).encode("utf8"),
  MemoryError"

What might the problem be? I am using raspberry Pi 2 with a 16gb SD card. I still have 8gb data free but still getting this error. Kindly help

Answer 1

This error is coming up because, it seems, pip's caching mechanism is trying to read the entire file into memory before caching it… which poses a problem in a limited-memory environment, as matplotlib is ~50mb.

A simpler solution, until pip is patched to use a constant-space caching algorithm, is to run pip with --no-cache-dir to avoid the cache:

$ pip --no-cache-dir install matplotlib