Is it possible to have one process reading an HDF5 file while another
one is writing to it? We currently have some code written in C++ that
writes a dataset regularly, and another process in Python (and sometimes
third processes in C++) that reads from it. This often leads to the
reader saying the node written by the writer does not exist. Here's an
example done at a pair of IPython terminals (sessions interleaved).
--------------1
In [4]: fyle = tables.openFile("spam.h5",mode="a")
---2
In [2]: fyle = tables.openFile("spam.h5")
IOError: file ``spam.h5`` exists but it is not an HDF5 file
In [6]: fyle.flush()
In [3]: fyle = tables.openFile("spam.h5")
In [4]: fyle.root._v_children.keys()
Out[4]: []
In [7]: fyle.createArray("/", "test01", numpy.arange(10))
Out[7]:
/test01 (Array(10,)) ''
atom := Int64Atom(shape=(), dflt=0)
maindim := 0
flavor := 'numpy'
byteorder := 'little'
chunkshape := None
In [5]: fyle.root._v_children.keys()
Out[5]: []
In [8]: fyle.flush()
In [6]: fyle.root._v_children.keys()
Out[6]: []
In [7]: fyle.root._f_getChild("test01")
ERROR: An unexpected error occurred while tokenizing input
The following traceback may be corrupted or invalid
The error message is: ('EOF in multi-line statement', (132, 0))
---------------------------------------------------------------------------
NoSuchNodeError Traceback (most recent call last)
[traceback omitted...]
NoSuchNodeError: group ``/`` does not have a child named ``test01``
----------------------------------
Is there a way to get a File object to refresh itself from disk? Or do
I need to close and re-open the file? Is this caused by the underlying
HDF5 libraries, or a caching issue in PyTables itself?
--
Anthony Foglia
Princeton Consultants
(609) 987-8787 x233
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