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  1. Apache Arrow
  2. ARROW-2963

[Python] Deadlock during fork-join and use_threads=True

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 0.10.0
    • Fix Version/s: 0.10.0
    • Component/s: Python
    • Environment:
      pandas==0.23.3
      pyarrow==0.10.0rc0

      Description

      The following code passes:

      import os
      import pandas as pd
      import pyarrow as pa
      
      
      df = pd.DataFrame({'x': [1]})
      table = pa.Table.from_pandas(df)
      df = table.to_pandas(use_threads=False)
      
      pid = os.fork()
      if pid != 0:
          os.waitpid(pid, 0)
      

      but the following code will never finish (the waitpid calls blocks forever, seems that the child process is frozen):

      import os
      import pandas as pd
      import pyarrow as pa
      
      
      df = pd.DataFrame({'x': [1]})
      table = pa.Table.from_pandas(df)
      df = table.to_pandas(use_threads=True)
      
      pid = os.fork()
      if pid != 0:
          os.waitpid(pid, 0)
      

      (the only difference is use_threads=True)

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              • Assignee:
                pitrou Antoine Pitrou
                Reporter:
                marco.neumann.by Marco Neumann
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                  Updated:
                  Resolved:

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