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8 Commits
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Dennis Heimbigner
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f1a3a64b65 |
Cleanup the handling of cache parameters.
re: https://github.com/Unidata/netcdf-c/issues/2733 When addressing the above issue, I noticed that there was a disconnect in NCZarr between nc_set_chunk_cache and nc_set_var_chunk cache. Specifically, setting nc_set_chunk_cache had no impact on the per-variable cache parameters when nc_set_var_chunk_cache was not used. So, modified the NCZarr code so that the per-variable cache parameters are set in this order (#1 is first choice): 1. The values set by nc_set_var_chunk_cache 2. The values set by nc_set_chunk_cache 3. The defaults set by configure.ac |
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Dennis Heimbigner
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231ae96c4b |
Add support for Zarr string type to NCZarr
* re: https://github.com/Unidata/netcdf-c/pull/2278 * re: https://github.com/Unidata/netcdf-c/issues/2485 * re: https://github.com/Unidata/netcdf-c/issues/2474 This PR subsumes PR https://github.com/Unidata/netcdf-c/pull/2278. Actually is a bit an omnibus covering several issues. ## PR https://github.com/Unidata/netcdf-c/pull/2278 Add support for the Zarr string type. Zarr strings are restricted currently to be of fixed size. The primary issue to be addressed is to provide a way for user to specify the size of the fixed length strings. This is handled by providing the following new attributes special: 1. **_nczarr_default_maxstrlen** — This is an attribute of the root group. It specifies the default maximum string length for string types. If not specified, then it has the value of 64 characters. 2. **_nczarr_maxstrlen** — This is a per-variable attribute. It specifies the maximum string length for the string type associated with the variable. If not specified, then it is assigned the value of **_nczarr_default_maxstrlen**. This PR also requires some hacking to handle the existing netcdf-c NC_CHAR type, which does not exist in zarr. The goal was to choose numpy types for both the netcdf-c NC_STRING type and the netcdf-c NC_CHAR type such that if a pure zarr implementation read them, it would still work and an NC_CHAR type would be handled by zarr as a string of length 1. For writing variables and NCZarr attributes, the type mapping is as follows: * "|S1" for NC_CHAR. * ">S1" for NC_STRING && MAXSTRLEN==1 * ">Sn" for NC_STRING && MAXSTRLEN==n Note that it is a bit of a hack to use endianness, but it should be ok since for string/char, the endianness has no meaning. For reading attributes with pure zarr (i.e. with no nczarr atribute types defined), they will always be interpreted as of type NC_CHAR. ## Issue: https://github.com/Unidata/netcdf-c/issues/2474 This PR partly fixes this issue because it provided more comprehensive support for Zarr attributes that are JSON valued expressions. This PR still does not address the problem in that issue where the _ARRAY_DIMENSION attribute is incorrectly set. Than can only be fixed by the creator of the datasets. ## Issue: https://github.com/Unidata/netcdf-c/issues/2485 This PR also fixes the scalar failure shown in this issue. It generally cleans up scalar handling. It also adds a note to the documentation describing that NCZarr supports scalars while Zarr does not and also how scalar interoperability is achieved. ## Misc. Other Changes 1. Convert the nczarr special attributes and keys to be all lower case. So "_NCZARR_ATTR" now used "_nczarr_attr. Support back compatibility for the upper case names. 2. Cleanup my too-clever-by-half handling of scalars in libnczarr. |
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Dennis Heimbigner
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3ffe7be446 |
Enhance/Fix filter support
re: Discussion https://github.com/Unidata/netcdf-c/discussions/2214 The primary change is to support so-called "standard filters". A standard filter is one that is defined by the following netcdf-c API: ```` int nc_def_var_XXX(int ncid, int varid, size_t nparams, unsigned* params); int nc_inq_var_XXXX(int ncid, int varid, int* usefilterp, unsigned* params); ```` So for example, zstandard would be a standard filter by defining the functions *nc_def_var_zstandard* and *nc_inq_var_zstandard*. In order to define these functions, we need a new dispatch function: ```` int nc_inq_filter_avail(int ncid, unsigned filterid); ```` This function, combined with the existing filter API can be used to implement arbitrary standard filters using a simple code pattern. Note that I would have preferred that this function return a list of all available filters, but HDF5 does not support that functionality. So this PR implements the dispatch function and implements the following standard functions: + bzip2 + zstandard + blosc Specific test cases are also provided for HDF5 and NCZarr. Over time, other specific standard filters will be defined. ## Primary Changes * Add nc_inq_filter_avail() to netcdf-c API. * Add standard filter implementations to test use of *nc_inq_filter_avail*. * Bump the dispatch table version number and add to all the relevant dispatch tables (libsrc, libsrcp, etc). * Create a program to invoke nc_inq_filter_avail so that it is accessible to shell scripts. * Cleanup szip support to properly support szip when HDF5 is disabled. This involves detecting libsz separately from testing if HDF5 supports szip. * Integrate shuffle and fletcher32 into the existing filter API. This means that, for example, nc_def_var_fletcher32 is now a wrapper around nc_def_var_filter. * Extend the Codec defaulting to allow multiple default shared libraries. ## Misc. Changes * Modify configure.ac/CMakeLists.txt to look for the relevant libraries implementing standard filters. * Modify libnetcdf.settings to list available standard filters (including deflate and szip). * Add CMake test modules to locate libbz2 and libzstd. * Cleanup the HDF5 memory manager function use in the plugins. * remove unused file include//ncfilter.h * remove tests for the HDF5 memory operations e.g. H5allocate_memory. * Add flag to ncdump to force use of _Filter instead of _Deflate or _Shuffle or _Fletcher32. Used for testing. |
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Dennis Heimbigner
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446348ed18 |
Add complete bitgroom support to NCZarr
re: PR https://github.com/Unidata/netcdf-c/pull/2088 re: PR https://github.com/Unidata/netcdf-c/pull/2130 replaces: https://github.com/Unidata/netcdf-c/pull/2140 Changes: * Add NCZarr-specific quantize functions to the dispatch table. * Copy (modified) quantize code from libhdf5 to NCZarr * Add quantize invocation to zvar.c * Add support for _QuantizeBitgroomNumberOfSignificantDigits and _QuantizeGranularBitgroomNumberOfSignificantDigits to ncgen. * Modify nc_test4/tst_quantize.c to allow it to be used both for hdf5 and for nczarr. * Make dap4 properly handle quantize functions in dispatch table. * Add quantize attribute support to ncgen. Other changes: * Caught and fixed some S3 problems * Fixed some nczarr fillvalue problems. * Fixed some nczarr cache problems. * Cleanup some flaws in libdispatch/dinfermodel.c * Allow byterange requests to S3 be readable by dinfermodel.c/check_file_type * Remove the libnczarr ztracedispatch code (big change). |
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Dennis Heimbigner
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11fe00ea05 |
Add filter support to NCZarr
Filter support has three goals: 1. Use the existing HDF5 filter implementations, 2. Allow filter metadata to be stored in the NumCodecs metadata format used by Zarr, 3. Allow filters to be used even when HDF5 is disabled Detailed usage directions are define in docs/filters.md. For now, the existing filter API is left in place. So filters are defined using ''nc_def_var_filter'' using the HDF5 style where the id and parameters are unsigned integers. This is a big change since filters affect many parts of the code. In the following, the terms "compressor" and "filter" and "codec" are generally used synonomously. ### Filter-Related Changes: * In order to support dynamic loading of shared filter libraries, a new library was added in the libncpoco directory; it helps to isolate dynamic loading across multiple platforms. * Provide a json parsing library for use by plugins; this is created by merging libdispatch/ncjson.c with include/ncjson.h. * Add a new _Codecs attribute to allow clients to see what codecs are being used; let ncdump -s print it out. * Provide special headers to help support compilation of HDF5 filters when HDF5 is not enabled: netcdf_filter_hdf5_build.h and netcdf_filter_build.h. * Add a number of new test to test the new nczarr filters. * Let ncgen parse _Codecs attribute, although it is ignored. ### Plugin directory changes: * Add support for the Blosc compressor; this is essential because it is the most common compressor used in Zarr datasets. This also necessitated adding a CMake FindBlosc.cmake file * Add NCZarr support for the big-four filters provided by HDF5: shuffle, fletcher32, deflate (zlib), and szip * Add a Codec defaulter (see docs/filters.md) for the big four filters. * Make plugins work with windows by properly adding __declspec declaration. ### Misc. Non-Filter Changes * Replace most uses of USE_NETCDF4 (deprecated) with USE_HDF5. * Improve support for caching * More fixes for path conversion code * Fix misc. memory leaks * Add new utility -- ncdump/ncpathcvt -- that does more or less the same thing as cygpath. * Add a number of new test to test the non-filter fixes. * Update the parsers * Convert most instances of '#ifdef _MSC_VER' to '#ifdef _WIN32' |
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Dennis Heimbigner
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74b40fd788 |
Upgrade the nczarr code to match Zarr V2
Re: https://github.com/zarr-developers/zarr-python/pull/716 The Zarr version 2 spec has been extended to include the ability to choose the dimension separator in chunk name keys. The legal separators has been extended from {'.'} to {'.' '/'}. So now it is possible to use a key like "0/1/2/0" for chunk names. This PR implements this for NCZarr. The V2 spec now says that this separator can be set on a per-variable basis. For now, I have chosen to allow this be set only globally by adding a key named "ZARR.DIMENSION_SEPARATOR=<char>" in the .daprc/.dodsrc/ncrc file. Currently, the only legal separator characters are '.' (the default) and '/'. On writing, this key will only be written if its value is different than the default. This change caused problems because supporting a separator of '/' is difficult to parse when keys/paths use '/' as the path separator. A test case was added for this. Additionally, make nczarr be enabled default by default. This required some additional changes so that if zip and/or AWS S3 sdk are unavailable, then they are disabled for NCZarr. In addition the following unrelated changes were made. 1. Tested that pure-zarr mode could read an nczarr formatted store. 1. The .rc file handling now merges all known .rc files (.ncrc,.daprc, and .dodsrc) in that order and using those in HOME first, then in current directory. For duplicate entries, the later ones override the earlier ones. This change is to remove some of the conflicts inherent in the current .rc file load process. A set of test cases was also added. 1. Re-order tests in configure.ac and CMakeLists.txt so that if libcurl is not found then the other options that depend upon it properly are disabled. 1. I decided that xarray support should be enabled by default for pure zarr. In order to allow disabling, I added a new mode flag "noxarray". 1. Certain test in nczarr_test depend on use of .dodsrc. In order for these to work when testing in parallel, some inter-test dependencies needed to be added. 1. Improved authorization testing to use changes in thredds.ucar.edu |
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Dennis Heimbigner
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eb3d9eb0c9 |
Provide a Number of fixes/improvements to NCZarr
Primary changes: * Add an improved cache system to speed up performance. * Fix NCZarr to properly handle scalar variables. Misc. Related Changes: * Added unit tests for extendible hash and for the generic cache. * Add config parameter to set size of the NCZarr cache. * Add initial performance tests but leave them unused. * Add CRC64 support. * Move location of ncdumpchunks utility from /ncgen to /ncdump. * Refactor auth support. Misc. Unrelated Changes: * More cleanup of the S3 support * Add support for S3 authentication in .rc files: HTTP.S3.ACCESSID and HTTP.S3.SECRETKEY. * Remove the hashkey from the struct OBJHDR since it is never used. |
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Dennis Heimbigner
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59e04ae071 |
This PR adds EXPERIMENTAL support for accessing data in the
cloud using a variant of the Zarr protocol and storage format. This enhancement is generically referred to as "NCZarr". The data model supported by NCZarr is netcdf-4 minus the user-defined types and the String type. In this sense it is similar to the CDF-5 data model. More detailed information about enabling and using NCZarr is described in the document NUG/nczarr.md and in a [Unidata Developer's blog entry](https://www.unidata.ucar.edu/blogs/developer/en/entry/overview-of-zarr-support-in). WARNING: this code has had limited testing, so do use this version for production work. Also, performance improvements are ongoing. Note especially the following platform matrix of successful tests: Platform | Build System | S3 support ------------------------------------ Linux+gcc | Automake | yes Linux+gcc | CMake | yes Visual Studio | CMake | no Additionally, and as a consequence of the addition of NCZarr, major changes have been made to the Filter API. NOTE: NCZarr does not yet support filters, but these changes are enablers for that support in the future. Note that it is possible (probable?) that there will be some accidental reversions if the changes here did not correctly mimic the existing filter testing. In any case, previously filter ids and parameters were of type unsigned int. In order to support the more general zarr filter model, this was all converted to char*. The old HDF5-specific, unsigned int operations are still supported but they are wrappers around the new, char* based nc_filterx_XXX functions. This entailed at least the following changes: 1. Added the files libdispatch/dfilterx.c and include/ncfilter.h 2. Some filterx utilities have been moved to libdispatch/daux.c 3. A new entry, "filter_actions" was added to the NCDispatch table and the version bumped. 4. An overly complex set of structs was created to support funnelling all of the filterx operations thru a single dispatch "filter_actions" entry. 5. Move common code to from libhdf5 to libsrc4 so that it is accessible to nczarr. Changes directly related to Zarr: 1. Modified CMakeList.txt and configure.ac to support both C and C++ -- this is in support of S3 support via the awd-sdk libraries. 2. Define a size64_t type to support nczarr. 3. More reworking of libdispatch/dinfermodel.c to support zarr and to regularize the structure of the fragments section of a URL. Changes not directly related to Zarr: 1. Make client-side filter registration be conditional, with default off. 2. Hack include/nc4internal.h to make some flags added by Ed be unique: e.g. NC_CREAT, NC_INDEF, etc. 3. cleanup include/nchttp.h and libdispatch/dhttp.c. 4. Misc. changes to support compiling under Visual Studio including: * Better testing under windows for dirent.h and opendir and closedir. 5. Misc. changes to the oc2 code to support various libcurl CURLOPT flags and to centralize error reporting. 6. By default, suppress the vlen tests that have unfixed memory leaks; add option to enable them. 7. Make part of the nc_test/test_byterange.sh test be contingent on remotetest.unidata.ucar.edu being accessible. Changes Left TO-DO: 1. fix provenance code, it is too HDF5 specific. |