Additional HDF5 dataset chunk statistics

h5stat-chunks.py

import argparse
import json
import operator
from collections import defaultdict
from dataclasses import dataclass
from functools import partial, reduce
from typing import Union

import h5py
import numpy as np
from tabulate import tabulate


if h5py.h5.get_libversion() < (1, 14, 3):
    raise RuntimeError("Requires HDF5 library 1.14.3 or later")
elif not h5py.h5.get_config().ros3:
    pass
    # raise RuntimeError('HDF5 library must be built with ROS3 virtual file driver')


def get_cli_args():
    """Command-line arguments."""
    parser = argparse.ArgumentParser(
        description="Provide collective dataset chunk stats that h5stat does not do.",
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
    )
    parser.add_argument("h5file", help="Input HDF5 file name.", type=str)
    parser.add_argument(
        "--show", help="Print individual dataset stats", action="store_true"
    )
    parser.add_argument(
        "--json", help="Format individual dataset stats in JSON", action="store_true"
    )
    return parser.parse_args()


@dataclass(slots=True, frozen=True)
class ChunkStats:
    """Various chunk statistics for one HDF5 dataset."""

    name: str
    num_stored: int
    size: int
    stor_size: int
    min_size: int
    max_size: int
    extent_ratio: float
    page_bins: dict
    page_spread_anomaly: int

    def __post_init__(self):
        if self.extent_ratio > 1:
            raise ValueError(f"Chunk shape ratio greater than 1 for {self.name}")
        if self.page_spread_anomaly < 0:
            raise ValueError(f"Chunk file page spread anomaly negative for {self.name}")

    def to_dict(self):
        d = {
            "dataset": self.name,
            "chunks_stored": self.num_stored,
            "chunk_size": self.size,
            "stored_size": self.stor_size,
            "min_stored_chunk_size": self.min_size,
            "max_stored_chunk_size": self.max_size,
            "chunk_shape_ratio": self.extent_ratio,
        }
        if len(self.page_bins):
            d.update(
                {
                    "file_pages": self.page_bins,
                    "page_spread_anomaly": self.page_spread_anomaly,
                }
            )
        return d


def chunk_to_shape_ratio(chunk: tuple, shape: tuple) -> float:
    """Ratio of chunk to dataset shape extent."""
    ratio = 1
    for c, s in zip(chunk, shape):
        try:
            ratio *= min(1, c / s)
        except ZeroDivisionError:
            # Deal with 1D datasets without data...
            continue
    return ratio


def chunk_size_minmax(dset: h5py.Dataset) -> tuple[int, int]:
    """Find the smallest and largest chunk size for one HDF5 dataset."""
    chunk_sizes = list()

    def chunk_info(chunk_stor):
        chunk_sizes.append(chunk_stor.size)

    dset.id.chunk_iter(chunk_info)

    return min(chunk_sizes), max(chunk_sizes)


def chunk2page(dset: h5py.Dataset, page_size: int) -> dict:
    """Determine file page for each chunk.

    Only for files with "PAGE" file space strategy.
    """
    stinfo = defaultdict(int)

    def chunk_info(chunk_stor):
        start_page = np.floor(chunk_stor.byte_offset / page_size).astype(int) + 1
        end_page = (
            np.floor((chunk_stor.byte_offset + chunk_stor.size - 1) / page_size).astype(
                int
            )
            + 1
        )
        if start_page != end_page:
            raise ValueError(f"Chunk crosses file page boundary: {chunk_stor}")
        stinfo[start_page] += 1

    dset.id.chunk_iter(chunk_info)

    return stinfo


def dset_stats(
    name: str,
    h5obj: Union[h5py.Group, h5py.Dataset],
    dset_list: list[ChunkStats],
    page_size: int = 0,
) -> None:
    if isinstance(h5obj, h5py.Dataset):
        chunk_shape = h5obj.chunks
        if chunk_shape:
            chunk_nelem = reduce(operator.mul, chunk_shape, 1)
            if page_size:
                chunk_page = chunk2page(h5obj, page_size)
                num_chunks = reduce(operator.add, chunk_page.values(), 0)
                stored_size = h5obj.id.get_storage_size()
                page_spread = len(chunk_page) - np.ceil(stored_size / page_size).astype(
                    int
                )
            else:
                num_chunks = h5obj.id.get_num_chunks()
                stored_size = h5obj.id.get_storage_size()
                chunk_page = dict()
                page_spread = 0
            min_size, max_size = chunk_size_minmax(h5obj)
            dset_list.append(
                ChunkStats(
                    name=h5obj.name,
                    num_stored=num_chunks,
                    extent_ratio=chunk_to_shape_ratio(chunk_shape, h5obj.shape),
                    stor_size=stored_size,
                    min_size=min_size,
                    max_size=max_size,
                    size=h5obj.id.get_type().get_size() * chunk_nelem,
                    page_bins=chunk_page,
                    page_spread_anomaly=page_spread,
                )
            )


def chunk_stats_table(
    bin_hdr: str,
    bins: list,
    bin_fmt: Union[str, list[str]],
    stats_hdr: str,
    data: np.ndarray,
) -> str:
    # Calculate the histograms...
    hist, bins_ = np.histogram(data, bins=bins)
    bin_prcnt = 100 * hist / np.sum(hist)
    bin_cumsum_prcnt = 100 * np.cumsum(hist) / np.sum(hist)

    # Headers...
    prcnt_hdr = "% of total\nchunk. datasets"
    cumcum_prcnt_hdr = "cusum % of total\nchunk. datasets"
    # headers = [bin_hdr, stats_hdr, prcnt_hdr, cumcum_prcnt_hdr]

    tablefmt = "grid"
    if isinstance(bin_fmt, list):
        return tabulate(
            {
                bin_hdr: bin_fmt,
                stats_hdr: hist,
                prcnt_hdr: np.round(bin_prcnt, decimals=2),
                cumcum_prcnt_hdr: np.round(bin_cumsum_prcnt, decimals=2),
            },
            headers="keys",
            tablefmt=tablefmt,
        )
    else:
        return tabulate(
            {
                bin_hdr: [
                    f"{bins_[i]:{bin_fmt}} ≤ # < {bins[i+1]:{bin_fmt}}"
                    for i in range(len(bins_) - 1)
                ],
                stats_hdr: hist,
                prcnt_hdr: np.round(bin_prcnt, decimals=2),
                cumcum_prcnt_hdr: np.round(bin_cumsum_prcnt, decimals=2),
            },
            headers="keys",
            tablefmt=tablefmt,
        )


# ---------------------------------------------------------------------------- #

cli = get_cli_args()

dset_info = list()
with h5py.File(cli.h5file, mode="r") as f:
    fcpl = f.id.get_create_plist()
    page = fcpl.get_file_space_strategy()[0] == h5py.h5f.FSPACE_STRATEGY_PAGE
    if page:
        page_size = fcpl.get_file_space_page_size()
    else:
        f.visititems(partial(dset_stats, dset_list=dset_info, page_size=0))

if page and page_size:
    with h5py.File(cli.h5file, mode="r", page_buf_size=4 * page_size) as f:
        f.visititems(partial(dset_stats, dset_list=dset_info, page_size=page_size))

if cli.show:
    if cli.json:
        print(
            json.dumps([_.to_dict() for _ in sorted(dset_info, key=lambda d: d.name)])
        )
    else:
        for _ in sorted(dset_info, key=lambda d: d.name):
            if page:
                print(
                    f"dataset {_.name} stored_size={_.stor_size} chunks_stored={_.num_stored}"
                    f" chunk_size={_.size} chunk_shape_ratio={_.extent_ratio:.6g}"
                    f" file_pages={len(_.page_bins)} page_spread_anomaly={_.page_spread_anomaly}"
                )
            else:
                print(
                    f"dataset {_.name} stored_size={_.stor_size} chunks_stored={_.num_stored}"
                    f" chunk_size={_.size} chunk_shape_ratio={_.extent_ratio:.6g}"
                )
    raise SystemExit()

print(f"\nDataset chunk statistics for {cli.h5file}:")
print(f"Chunked datasets in the file: {len(dset_info)}")
if page:
    print(f'"PAGE" file space strategy with page size of {page_size:,} bytes.')
print("\n")

print(
    chunk_stats_table(
        "Chunk size in bytes",
        [0, 10, 1000, 10000, 100_000, 1_000_000, 10_000_000, np.inf],
        ".0e",
        "# chunked\ndatasets",
        [_.size for _ in dset_info],
    ),
    end="\n\n\n",
)

print(
    chunk_stats_table(
        "Chunk to dataset\nshape ratio",
        [
            0,
            0.001,
            0.002,
            0.003,
            0.004,
            0.005,
            0.01,
            0.02,
            0.03,
            0.04,
            0.05,
            0.1,
            0.25,
            1,
        ],
        ".3f",
        "# chunked\ndatasets",
        [_.extent_ratio for _ in dset_info],
    ),
    end="\n\n\n",
)

print(
    chunk_stats_table(
        "Chunks stored",
        [0, 1, 2, 10, 100, 1000, 10000, 100_000, np.inf],
        [
            "No chunks",
            "1 chunk",
            "2-9 chunks",
            "10-99 chunks",
            "100-999 chunks",
            "1000-9999 chunks",
            "10,000-99,999 chunks",
            "100,000 or more chunks",
        ],
        "# chunked\ndatasets",
        [_.num_stored for _ in dset_info],
    ),
    end="\n\n\n",
)

MiB = 1024 * 1024
print(
    chunk_stats_table(
        "Chunk cache size",
        [0, 1 * MiB, 4 * MiB, 8 * MiB, 16 * MiB, np.inf],
        ["1 MiB", "4 MiB", "8 MiB", "16 MiB", "> 16 MiB"],
        "# chunked\ndatasets",
        [_.size * _.num_stored for _ in dset_info],
    ),
    end="\n\n\n",
)

if page:
    print(
        chunk_stats_table(
            "# of file pages\nholding all chunks",
            [1, 2, 3, 4, 5, 6, 10, 15, 20, 25, 30, np.inf],
            [
                "1 page",
                "2 pages",
                "3 pages",
                "4 pages",
                "5 pages",
                "6 - 9 pages",
                "10 - 14 pages",
                "15 - 19 pages",
                "20 - 24 pages",
                "25 - 29 pages",
                "30 or more pages",
            ],
            "# chunked\ndatasets",
            [len(_.page_bins) for _ in dset_info],
        ),
        end="\n\n\n",
    )

    print(
        chunk_stats_table(
            "# file pages anomaly",
            [0, 1, 2, 3, 4, 5, np.inf],
            [
                "No extra file pages",
                "1 extra file page",
                "2 extra file pages",
                "3 extra file pages",
                "4 extra file pages",
                "5 or more extra file pages",
            ],
            "# chunked\ndatasets",
            [_.page_spread_anomaly for _ in dset_info],
        ),
        end="\n\n\n",
    )

    print(
        chunk_stats_table(
            "Max % of chunks\nin one file page",
            [0, 20, 40, 60, 80, 100],
            ".0f",
            "# chunked\ndatasets",
            [
                max(map(lambda x: 100 * x / _.num_stored, _.page_bins.values()))
                for _ in dset_info
            ],
        ),
        end="\n\n\n",
    )

Requires a more recent h5py, recommend at least version 3.9. Run it with --help to see available options.

Updated with three new stats about dataset chunks in files with PAGE file space strategy.

Added JSON format output and a few bug fixes.

Fix JSON output to be compliant.

Changes in version 13b49856:

• Switch to numpy for all histogram calculations.
• Use tabulate package to pretty-print output.
• Added a statistics about chunk cache size to fit all chunks of one dataset.
• Minimum required libhdf5 version is 1.14.3.

Changes in version 2c0e9427:

• Support for files in S3-compatible cloud stores. Both https:// and s3:// style object links can be used.
• libhdf5 with ROS3 virtual file driver required.

Only a few minor tweaks in version 835d936f.

Changes in 835d936f:

• New name: h5stat-extra.py
• Contiguous datasets are included.
• Two new stats for paged files: How many contiguous datasets or chunked datasets' chunks are stored outside of file pages (too large for one file page).
• Compact datasets are skipped due to their specific storage that does not influence the reported stats.
• Few changes to bin ranges to produce more relevant information.

Changes:

• Support for AWS env. variables for configuration and credentials files.
• Chunked datasets with chunks outside of file pages are removed prior to some paged file related statistics.
• Code cleanup and optimization.

Changes:

• Added stats for total stored size of chunked datasets.

Changes:

• Update for HDF5 2.0.0 when sourcing AWS-related information.
• —page-list option accepts two values: page and dataset. First presents info in the file page-centric way while the other does it in the dataset-centric way. Both output JSON.
• Added a 4 MB interval for the Chunk Size in Bytes table.