H5PHello all I am trying to explore my options for optimising group access. The issue I have is that for some operations users need to traverse a large group tree and collect information. The structure of the tree is as follows (for each level N# the number of links is indicated):
N1: 1-500 links N2: 3 links N3: 6 links N4: 10-300 links N5: 10-50 links N6: 1 link N7: 1 link I need to traverse N1->N2->N3->N4->100-300 N5 links->10-50 N6 links->N7->N8->Dataset attributes. This traversal takes some time for large examples. I am looking into using H5Pset_link_phase_change to improve performance, given that once the tree is created no more data is written into it and applications only read the data (they might write in other paths but i guess that's OK). The user documentation of H5Pset_link_phase_change is rather unclear and IMHO somehow obscurely written ( http://www.hdfgroup.org/HDF5/doc/RM/RM_H5G.html#Group-GroupStyles). Further, while compact and indexed formats are discussed in the user manual, compact and dense formats are defined in the reference manual ( http://www.hdfgroup.org/HDF5/doc/RM/RM_H5P.html#Property-SetLinkPhaseChange) which is also somehow obscure. Is there a clear explanation of what is what, any parametric performance results of using these group definitions, or any experience in the group? Thanks! -- Dimitris Servis
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