Ticket #2270 (new enhancement)

Opened 4 months ago

Last modified 4 months ago

Patch for HDF5 block size recognition

Reported by: jurien Assigned to: mloskot
Priority: normal Milestone: 1.5.3
Component: GDAL_Raster Version:
Severity: normal Keywords: HDF5
Cc: warmerdam, dnadeau

Description

Problem: HDF5 driver does not implement HDF chunk size detection. Simptoms: HDF5 is *very* slow on compressed files with chunksize != 1 line (default block size for HDF5 gdal driver)

I have modified the GDAL HDF5 driver to extract the chunk size and load it as the block size for the dataset.

Regards

Attachments

gdal-1.5.0-HDF5-chunksize.patch (2.7 kB) - added by jurien on 03/11/08 10:39:38.
patch to read chunksize from an HDF5 file and optimize reads

Change History

03/11/08 10:39:38 changed by jurien

  • attachment gdal-1.5.0-HDF5-chunksize.patch added.

patch to read chunksize from an HDF5 file and optimize reads

03/11/08 10:58:40 changed by warmerdam

  • keywords set to HDF5.
  • cc set to warmerdam, dnadeau.
  • component changed from default to GDAL_Raster.
  • milestone set to 1.5.2.

Mateusz,

As time permits please review and apply the patches. I am not aware autotests for HDF5. This should also be addressed as part of this effort.

03/11/08 10:59:06 changed by warmerdam

  • owner changed from warmerdam to mloskot.

03/11/08 11:57:28 changed by nowakpl

To me it looks like the patch would lead to incorrect memory layout for border blocks.

03/11/08 12:19:08 changed by jurien

@nowakpl: you mean if the blocksize is not a multiple of the imagesize? it is checked with at lines 304 and 308. I check for the size of the image and the boundaries of the block and keep the minimum of those. If that's not what you mean, please explain me what you meant so I can try and fix it.

Regards.