On 8 March 2011 01:18, Felipe Barriga Richards <fbarr...@algometrics.cl> wrote:
> On Thu, 2011-03-03 at 20:07 +0100, Francesc Alted wrote:
>> A Thursday 03 March 2011 16:33:37 Felipe Barriga Richards escrigué:
>> > Hi,
>> >
>> > I've been trying to open an H5 file from multiple processes as
>> > read-only and each process reads a different table. If I do this I
>> > get errors so I suspect that pytables doesn't support this ?
>> >
>> > I think that this shouldn't be a problem as I'm opening the file as
>> > read-only so it won't corrupt the file.
>> >
>> > Maybe there is a problem because of the cache that makes pytables of
>> > the file ?
>> >
>> > Any suggestions ?
>>
>> I don't see why this should not work. Could you send a self-contained
>> example reproducing the problem?
>>
>
> If I open the same file (or 2 files made with a symbolic link to the
> same file) I got this error when I try to read them:
[snip...]
> The Line 'File "./hdf5_server-multi.py", line 49, in run' is:
>
> results = table.where("(timestamp > 10)")
> for row in results:
>
> And I open the file with:
> h5File = tables.openFile("file1.h5", mode = "r")
Hi Felipe,
This is curious, I'm guessing that you're opening the file once, then
using multiple processes to access it. Can you send the lines before
line 49, or a subset that reproduces this behaviour?
> When I try the same but using copies of the file (not symbolic links) it
> work fine.
Well, copies are distinct files, so you wouldn't expect there to be a
problem. I'm guessing again, but this is probably only accidental - if
you loaded up more processes it would fail in the same way.
Cheers,
Tony
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