paleolimbot commented on code in PR #45459: URL: https://github.com/apache/arrow/pull/45459#discussion_r2015616569
########## cpp/src/parquet/geospatial_statistics.h: ########## @@ -0,0 +1,192 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +#pragma once + +#include <cmath> +#include <cstdint> +#include <memory> + +#include "parquet/platform.h" +#include "parquet/types.h" + +namespace parquet { + +/// \brief Structure represented encoded statistics to be written to and read from Parquet +/// serialized metadata. +/// +/// See the Parquet Thrift definition and GeoStatistics for the specific definition +/// of field values. +struct PARQUET_EXPORT EncodedGeoStatistics { + static constexpr double kInf = std::numeric_limits<double>::infinity(); + + double xmin{kInf}; + double xmax{-kInf}; + double ymin{kInf}; + double ymax{-kInf}; + double zmin{kInf}; + double zmax{-kInf}; + double mmin{kInf}; + double mmax{-kInf}; + std::vector<int32_t> geospatial_types; + + bool has_x() const { return !std::isinf(xmin - xmax); } + bool has_y() const { return !std::isinf(ymin - ymax); } + bool has_z() const { return !std::isinf(zmin - zmax); } + bool has_m() const { return !std::isinf(mmin - mmax); } + + bool is_set() const { + return !geospatial_types.empty() || has_x() || has_y() || has_z() || has_m(); + } +}; + +class GeoStatisticsImpl; + +/// \brief Base type for computing geospatial column statistics while writing a file +/// or representing them when reading a file +/// +/// Note that NaN values that were encountered within coordinates are omitted; however, +/// NaN values that were obtained via decoding encoded statistics are propagated. This +/// behaviour ensures C++ clients that are inspecting statistics via the column metadata +/// can detect the case where a writer generated NaNs (even though this implementation Review Comment: For NaNs in xmin, ymin, xmax, and ymax, I can't think of a way to make use of statistics that were set to NaN to skip a column chunk; however, the normal predicate pushdown I'm envisioning (a 2D rectangle) can still be done if Z or M dimensions were NaN. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
