id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type 1596115847,I_kwDOAMm_X85fIsuH,7549,HDF5-DIAG warnings calling `open_mfdataset` with more than `file_cache_maxsize` datasets (hdf5 1.12.2),132147,open,0,,,10,2023-02-23T02:28:23Z,2023-03-26T00:41:11Z,,CONTRIBUTOR,,,,"### What happened? Using `ds = open_mfdataset(...)` to open more than `file_cache_maxsize` files, then saving the combined dataset with `ds.to_netcdf()` prints many HDF5-DIAG warnings. This happens when using `hdf5==1.12.2` as bundled with `netcdf4~=1.6.0`. Downgrading to `netcdf4~=1.5.8` which bundles `hdf5==1.12.0` stops the warnings being printed. The output file appears to be correct in either case. ### What did you expect to happen? No warnings from HDF5-DIAG. Either raise an error because of the number of files being opened at once, or behaving as `open_mfdataset()` normally does. ### Minimal Complete Verifiable Example ```Python import argparse import pathlib import tempfile from typing import List import netCDF4 import xarray HERE = pathlib.Path(__file__).parent def add_arguments(parser: argparse.ArgumentParser): parser.add_argument('count', type=int, default=200, nargs='?') parser.add_argument('--file-cache-maxsize', type=int, required=False) def main(): parser = argparse.ArgumentParser() add_arguments(parser) opts = parser.parse_args() if opts.file_cache_maxsize is not None: xarray.set_options(file_cache_maxsize=opts.file_cache_maxsize) temp_dir = tempfile.mkdtemp(dir=HERE, prefix='work-dir-') work_dir = pathlib.Path(temp_dir) print(""Working in"", work_dir.name) print(""Making"", opts.count, ""datasets"") dataset_paths = make_many_datasets(work_dir, count=opts.count) print(""Combining"", len(dataset_paths), ""datasets"") dataset = xarray.open_mfdataset(dataset_paths, lock=False) dataset.to_netcdf(work_dir / 'combined.nc') def make_many_datasets( work_dir: pathlib.Path, count: int = 200 ) -> List[pathlib.Path]: dataset_paths = [] for i in range(count): variable = f'var_{i}' path = work_dir / f'{variable}.nc' dataset_paths.append(path) make_dataset(path, variable) return dataset_paths def make_dataset( path: pathlib.Path, variable: str, ) -> None: ds = netCDF4.Dataset(path, ""w"", format=""NETCDF4"") ds.createDimension(""x"", 1) var = ds.createVariable(variable, ""i8"", (""x"",)) var[:] = 1 ds.close() if __name__ == '__main__': main() ``` ### MVCE confirmation - [x] Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue in xarray. - [x] Complete example — the example is self-contained, including all data and the text of any traceback. - [x] Verifiable example — the example copy & pastes into an IPython prompt or [Binder notebook](https://mybinder.org/v2/gh/pydata/xarray/main?urlpath=lab/tree/doc/examples/blank_template.ipynb), returning the result. - [x] New issue — a search of GitHub Issues suggests this is not a duplicate. ### Relevant log output ```Python Working in work-dir-yi3jp5ly Making 128 datasets Combining 128 datasets HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 1: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeBitGroomNumberOfSignificantDigits' major: Attribute minor: Object not found HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 1: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeGranularBitRoundNumberOfSignificantDigits' major: Attribute minor: Object not found HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 1: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeBitRoundNumberOfSignificantBits' major: Attribute minor: Object not found HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 1: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeBitGroomNumberOfSignificantDigits' major: Attribute minor: Object not found HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 1: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeGranularBitRoundNumberOfSignificantDigits' major: Attribute minor: Object not found HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 1: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeBitRoundNumberOfSignificantBits' major: Attribute minor: Object not found HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 2: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeBitGroomNumberOfSignificantDigits' major: Attribute minor: Object not found HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 2: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeGranularBitRoundNumberOfSignificantDigits' major: Attribute minor: Object not found HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 2: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeBitRoundNumberOfSignificantBits' major: Attribute minor: Object not found HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 3: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeBitGroomNumberOfSignificantDigits' major: Attribute minor: Object not found HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 3: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeGranularBitRoundNumberOfSignificantDigits' major: Attribute minor: Object not found HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 3: #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute major: Attribute minor: Can't open object #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed major: Virtual Object Layer minor: Can't open object #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute major: Attribute minor: Can't open object #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header major: Attribute minor: Unable to initialize object #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeBitRoundNumberOfSignificantBits' major: Attribute minor: Object not found ``` ### Anything else we need to know? The example is a script to run on the command line. Assuming the file is named `test.py`, invoke as: ```shell # This will show the error. Defaults to making 200 files $ python3 ./test.py # This will not show the error - the number of files is less than file_cache_maxsize: $ python3 ./test.py 127 # This will adjust file_cache_maxsize to show the error again, despite the lower number of files $ python3 ./test.py 11 --file-cache-maxsize=10 ``` The log output is from `python3 ./test.py 128`. The length of the log output depends on the number of files opened - the more files the longer the log. The log output from `python3 ./test.py` using the default of 200 datasets was too long to include in this issue! All output files are restricted to directories created in the current working directory named `work-dir-XXXXXXX`, and are retained after the program exits. 200 datasets take up a total of 1.7MB. ### Environment Failing environment:
INSTALLED VERSIONS ------------------ commit: None python: 3.8.10 (default, Nov 14 2022, 12:59:47) [GCC 9.4.0] python-bits: 64 OS: Linux OS-release: 5.15.0-58-generic machine: x86_64 processor: x86_64 byteorder: little LC_ALL: None LANG: en_AU.UTF-8 LOCALE: ('en_AU', 'UTF-8') libhdf5: 1.12.2 libnetcdf: 4.9.0 xarray: 2023.1.0 pandas: 1.5.3 numpy: 1.24.2 scipy: None netCDF4: 1.6.2 pydap: None h5netcdf: None h5py: None Nio: None zarr: None cftime: 1.6.2 nc_time_axis: None PseudoNetCDF: None rasterio: None cfgrib: None iris: None bottleneck: None dask: 2023.2.0 distributed: None matplotlib: None cartopy: None seaborn: None numbagg: None fsspec: 2023.1.0 cupy: None pint: None sparse: None flox: None numpy_groupies: None setuptools: 44.0.0 pip: 23.0.1 conda: None pytest: None mypy: None IPython: None sphinx: None
Working environment:
INSTALLED VERSIONS ------------------ commit: None python: 3.8.10 (default, Nov 14 2022, 12:59:47) [GCC 9.4.0] python-bits: 64 OS: Linux OS-release: 5.15.0-58-generic machine: x86_64 processor: x86_64 byteorder: little LC_ALL: None LANG: en_AU.UTF-8 LOCALE: ('en_AU', 'UTF-8') libhdf5: 1.12.0 libnetcdf: 4.7.4 xarray: 2023.1.0 pandas: 1.5.3 numpy: 1.24.2 scipy: None netCDF4: 1.5.8 pydap: None h5netcdf: None h5py: None Nio: None zarr: None cftime: 1.6.2 nc_time_axis: None PseudoNetCDF: None rasterio: None cfgrib: None iris: None bottleneck: None dask: 2023.2.0 distributed: None matplotlib: None cartopy: None seaborn: None numbagg: None fsspec: 2023.1.0 cupy: None pint: None sparse: None flox: None numpy_groupies: None setuptools: 44.0.0 pip: 23.0.1 conda: None pytest: None mypy: None IPython: None sphinx: None
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