HDF5 Fine-tuning the Metadata Cache Documentation

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Fine-tuning the Metadata Cache Documentation

The purpose of this page is to list and briefly describe the documentation available to those who want to fine-tune how the metadata cache behaves. The following are the sections on this page:

HDF5 Library APIs
Fine-tuning the Metadata Cache Design Documents

HDF5 Library APIs

The APIs listed below will be incorporated into the HDF5 Reference Manual when this new feature is fully released.

H5Fget_metadata_read_retry_info	Retrieves the collection of read retries for metadata items with checksum.

H5Pget_metadata_read_attempts	Retrieves the number of read attempts from a file access property list.

H5Pset_metadata_read_attempts	Sets the number of read attempts in a file access property list.

H5Dflush	Causes all buffers associated with a dataset to be immediately written to disk without removing the data from the cache.

H5Drefresh	Causes all buffers associated with a dataset to be cleared and immediately re-loaded with updated contents from disk storage.

H5Gflush	Causes all buffers associated with a group to be immediately flushed to disk without removing the data from the cache.

H5Grefresh	Causes all buffers associated with a group to be cleared and immediately re-loaded with updated contents from disk storage.

H5Oflush	Causes all buffers associated with an object to be immediately flushed to disk without removing the data from the cache.

H5Orefresh	Causes all buffers associated with an object to be cleared and immediately re-loaded with updated contents from disk storage.

H5Tflush	Causes all buffers associated with a committed datatype to be immediately flushed to disk without removing the data from the cache.

H5Trefresh	Causes all buffers associated with a committed datatype to be cleared and immediately re-loaded with updated contents from disk storage.

H5Fget_intent	Determines the read/write or read-only status of a file.

Logging APIs

The APIs listed below will be incorporated into the HDF5 Reference Manual when this new feature is fully released.

H5Pset_mdc_log_options	Sets metadata cache logging options.

H5Pget_mdc_log_options	Gets metadata cache logging options.

H5Fstart_mdc_logging	Starts logging metadata cache events if logging was previously enabled.

H5Fstop_mdc_logging	Stops logging metadata cache events if logging was previously enabled and is currently ongoing.

H5Fget_mdc_logging_status	Gets the current metadata cache logging status.

Fine-tuning the Metadata Cache Design Documents
The design documents listed below provide background information for the functions that have been developed to provide better control of the metadata cache and why better control might be useful.

Fine-grained Control of Metadata Cache Flushes	This document describes some new functions which allow dynamic, fine-grained flush control of the entire metadata cache and the caches related to individual HDF5 objects.

Read Attempts for Metadata with Checksum	The HDF5 Library encounters intermittent checksum failures from reading metadata of an HDF5 file opened with single-writer/multiple-reader (SWMR) access. The failure is from a checksum check that does not reflect the data read. This document describes the modifications to the library that address this problem.

Metadata Cache Logging	This document describes the improvements made to the library’s metadata cache logging facility. The changes include APIs that can be used to control logging operations and the format of log messages.

Flush Dependency Testing	This document considers how to design tests for flush dependencies of metadata cache items for single-writer/multiple-reader (SWMR) access.

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Last modified: 31 March 2016