Hi Dimitris,
On Jan 20, 2011, at 9:00 AM, Dimitris Servis wrote:
> Hi Quincey
>
> thanks for the response, is this code available (AFAIK there's only 1.9.x
> development snapshots)?
Right now, this code is available in a branch, but I can create a
snapshot for you to experiment with, if you'd like. Send me email off the
list, if so.
> When is it planned to be released officially?
Elena and I are working on a release schedule for the 1.10.0 release,
but it's not done yet. We'll post something to the list when we have something
available.
Quincey
> thanks again!
>
> Best
>
> -- dimitris
>
> 2011/1/20 Quincey Koziol <[email protected]>
> Hi Dimitris,
>
> On Jan 20, 2011, at 8:05 AM, Dimitris Servis wrote:
>
> > Hi all,
> >
> > one of the major problems that I have in synchronizing reads and writes
> > with HDF5 files and locks is the update of metadata. Here' s some
> > pseudoflows that show the problem:
> >
> > Process 1:
> > 1. Create file file.h5
> > 2. Start process 2
> > 3. Wait until file can be locked
> > 4. Read /dataset
> >
> > Process 2:
> > 1. Open file file.h5
> > 2. Get exclusive lock
> > 3. Write /dataset
> > 4. Unlock and close the file
> >
> > My locks work on the file handle returned by H5Fget_vfd_handle and always
> > lock the first byte. This is the only way I could find to synchronize
> > between threads and processes. this works fine so far, what I would like to
> > do now is this: Process 1 at step (4) will not read the dataset, because
> > the file handle in process 1 is opened before process B writes into the
> > file. What I would like to do is have a way to "refresh" the metadata. The
> > ways to do that are:
> >
> > 1. Close and reopen the file, but that will lose me the lock
> > 2. Lock on an OS handle and then open the HDF5 handle. That will work on
> > Linux but not windows as the HDF5 handle will not be able to read.
> > 3. Do it in a VFD driver but then locking/unlocking is not controlled by
> > the program.
> >
> > What I really would like to have is a function that simply forces the
> > metadata to be re-read from the same open file handle. Is there any such
> > function that is available for sharing? Otherwise I will try to write one.
>
> We have implemented this functionality for the 1.10 release.
>
> Quincey
>
>
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