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Quincey Koziol <koziol@xxxxxxxxxxxx> writes: > The problem is in your computation of the chunk size for the > dataset, in libsrc4/nc4hdf.c, around lines 1059-1084. The current > computations end up with a chunk of size equal to the dimension size > (2147483644/4 in the code below), i.e. a single 4GB chunk for the > entire dataset. This is not going to work well, since HDF5 always > reads an entire chunk into memory, updates it and then writes the > entire chunk back out to disk. ;-) > > That section of code looks like it has the beginning of some > heuristics for automatically tuning the chunk size, but it would > probably be better to let the application set a particular chunk > size, if possible. > Ah ha! Well, that's not going to work! What would be a good chunksize for this (admittedly weird) test case: writing one value at a time for a huge array. Would a chunksize of one be crazy? Or the right size? Thanks! Ed -- Ed Hartnett -- ed@xxxxxxxxxxxxxxxx
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