JingsongLi commented on code in PR #9850: URL: https://github.com/apache/paimon/pull/9850#discussion_r4056525648
########## paimon-python/pypaimon/read/reader/parquet_page_index_reader.py: ########## @@ -0,0 +1,630 @@ +# 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. + +"""Read contiguous Parquet row windows using their OffsetIndex. + +Selected encoded pages are placed in bounded, in-memory Parquet files. PyArrow +still decodes the pages, including dictionary and compression encodings. Source +files are never rewritten. Nested fields retain their complete physical schema +and align their leaf columns at common row boundaries. Files without indexes and +disjoint ranges use the normal reader: per-page seeks can amplify requests in +filesystems that prefetch remote data (including Jindo). +""" + +import base64 +import bisect +import struct + +import pyarrow as pa +import pyarrow.parquet as pq + + +# Bound encoded page data retained by the temporary column files. +_MAX_PAGE_BYTES = 32 * 1024 * 1024 +# Bound the generic FileMetaData tree before creating Python objects for it. +_MAX_FOOTER_BYTES = 1024 * 1024 +_MAX_FOOTER_COLUMN_CHUNKS = 1024 +# Bound all serialized OffsetIndexes and their retained typed PageLocations. +_MAX_INDEX_BYTES = 8 * 1024 * 1024 +_MAX_PAGE_LOCATIONS = 128 * 1024 + + +class _PageIndexBudgetExceeded(Exception): + pass + + +class _Compact: + """Thrift compact values used by Parquet metadata (no generated bindings).""" + + def __init__(self, data): + self.data = memoryview(data) + self.position = 0 + + def take(self, size): + end = self.position + size + if size < 0 or end > len(self.data): + raise ValueError("Truncated Parquet page-index metadata") + result = self.data[self.position:end] + self.position = end + return result + + def unsigned(self): + result = 0 + for shift in range(0, 70, 7): + value = self.take(1)[0] + result |= (value & 127) << shift + if value < 128: + return result + raise ValueError("Invalid Parquet compact integer") + + def value(self, kind, depth=0): + if depth > 64: + raise ValueError("Parquet metadata nesting exceeds 64 levels") + if kind in (1, 2): + return kind == 1 + if kind == 3: + return self.take(1).tobytes() + if kind in (4, 5, 6): + value = self.unsigned() + return (value >> 1) ^ -(value & 1) + if kind == 7: + return self.take(8).tobytes() + if kind == 8: + return self.take(self.unsigned()).tobytes() + if kind in (9, 10): + header = self.take(1)[0] + count, element = header >> 4, header & 15 + if count == 15: + count = self.unsigned() + if count > len(self.data) - self.position: + raise ValueError("Invalid Parquet compact collection size") + return element, [ + self.value(self.take(1)[0] if element in (1, 2) else element, depth + 1) + for _ in range(count) + ] + if kind == 12: + fields = {} + previous = 0 + while True: + header = self.take(1)[0] + if header == 0: + return fields + delta, field_kind = header >> 4, header & 15 + field = previous + delta if delta else self.value(4) + if field in fields: + raise ValueError("Duplicate Parquet compact field") + fields[field] = field_kind, self.value(field_kind, depth + 1) + previous = field + raise ValueError("Unsupported Parquet compact type: {}".format(kind)) + + +class _OffsetIndexDecoder: + """Decode typed PageLocations without materializing generic Thrift trees.""" + + def __init__(self, data, max_locations): + self.parser = _Compact(data) + self.max_locations = max_locations + # PageLocations retain three fields each. Allow the standard optional + # per-page byte-count list plus a small amount of forward metadata. + self.remaining_items = max_locations * 6 + 16 + + def decode(self): + locations = None + previous = 0 + while True: + field = self._field(previous) + if field is None: + break + field_id, kind = field + previous = field_id + if field_id == 1: + if locations is not None: + raise ValueError("Duplicate Parquet OffsetIndex field") + if kind != 9: + raise ValueError("Invalid Parquet OffsetIndex page locations") + locations = self._locations() + else: + self._skip(kind) + if locations is None or self.parser.position != len(self.parser.data): + raise ValueError("Invalid Parquet OffsetIndex") + return locations + + def _field(self, previous): + header = self.parser.take(1)[0] + if header == 0: + return None + delta, kind = header >> 4, header & 15 + field = previous + delta if delta else self.parser.value(4) + if field <= 0: + raise ValueError("Invalid Parquet compact field") + self._consume(1) + return field, kind + + def _collection(self): + header = self.parser.take(1)[0] + count, element = header >> 4, header & 15 + if count == 15: + count = self.parser.unsigned() + if count > len(self.parser.data) - self.parser.position: + raise ValueError("Invalid Parquet compact collection size") + return count, element + + def _locations(self): + count, element = self._collection() + if element != 12: + raise ValueError("Invalid Parquet OffsetIndex page locations") + if count > self.max_locations: + raise _PageIndexBudgetExceeded( + "Parquet OffsetIndex exceeds page-location budget") + self._consume(count) + return [self._location() for _ in range(count)] + + def _location(self): + values = [None, None, None] + expected = (6, 5, 6) + previous = 0 + while True: + field = self._field(previous) + if field is None: + break + field_id, kind = field + previous = field_id + if 1 <= field_id <= 3: + if values[field_id - 1] is not None: + raise ValueError("Duplicate Parquet PageLocation field") + if kind != expected[field_id - 1]: + raise ValueError("Invalid Parquet PageLocation field type") + values[field_id - 1] = self.parser.value(kind) + else: + self._skip(kind) + if any(value is None for value in values): + raise ValueError("Missing Parquet PageLocation field") + offset, size, first_row = values + if offset < 0 or size <= 0 or first_row < 0: + raise ValueError("Invalid Parquet PageLocation") + return offset, size, first_row + + def _consume(self, count): + if count > self.remaining_items: + raise _PageIndexBudgetExceeded( + "Parquet compact metadata exceeds object budget") + self.remaining_items -= count + + def _skip_collection_value(self, kind, depth): + if kind in (1, 2): + actual = self.parser.take(1)[0] + if actual not in (1, 2): + raise ValueError("Invalid Parquet compact boolean") + else: + self._skip(kind, depth) + + def _skip(self, kind, depth=0): + if depth > 64: + raise ValueError("Parquet metadata nesting exceeds 64 levels") + if kind in (1, 2): + return + if kind == 3: + self.parser.take(1) + return + if kind in (4, 5, 6): + self.parser.unsigned() + return + if kind == 7: + self.parser.take(8) + return + if kind == 8: + self.parser.take(self.parser.unsigned()) + return + if kind in (9, 10): + count, element = self._collection() + self._consume(count) + for _ in range(count): + self._skip_collection_value(element, depth + 1) + return + if kind == 11: + count = self.parser.unsigned() + self._consume(count * 2) + if count: + kinds = self.parser.take(1)[0] + key_kind, value_kind = kinds >> 4, kinds & 15 + for _ in range(count): + self._skip_collection_value(key_kind, depth + 1) + self._skip_collection_value(value_kind, depth + 1) + return + if kind == 12: + previous = 0 + while True: + field = self._field(previous) + if field is None: + return + field_id, field_kind = field + previous = field_id + self._skip(field_kind, depth + 1) + raise ValueError("Unsupported Parquet compact type: {}".format(kind)) + + +def _decode_offset_index(data, max_locations): + return _OffsetIndexDecoder(data, max_locations).decode() + + +def _unsigned(value): + result = bytearray() + while value >= 128: + result.append((value & 127) | 128) + value >>= 7 + result.append(value) + return bytes(result) + + +def _encode(kind, value): + if kind in (1, 2): + return bytes([1 if value else 2]) + if kind in (3, 7): + return value + if kind in (4, 5, 6): + return _unsigned(value * 2 if value >= 0 else -value * 2 - 1) + if kind == 8: + return _unsigned(len(value)) + value + if kind in (9, 10): + element, items = value + size = len(items) + header = bytes([(min(size, 15) << 4) | element]) + if size >= 15: + header += _unsigned(size) + return header + b"".join(_encode(element, item) for item in items) + if kind == 12: + result = bytearray() + previous = 0 + for field, (field_kind, item) in sorted(value.items()): + delta = field - previous + if field_kind in (1, 2): + field_kind = 1 if item else 2 + if 0 < delta < 16: + result.append((delta << 4) | field_kind) + else: + result.append(field_kind) + result.extend(_encode(4, field)) + if field_kind not in (1, 2): + result.extend(_encode(field_kind, item)) + previous = field + result.append(0) + return bytes(result) + raise ValueError("Unsupported Parquet compact type: {}".format(kind)) + + +def _get(fields, field, default=None): + return fields[field][1] if field in fields else default + + +def _read_exact(source, offset, length): + if offset < 4 or length <= 0: + raise ValueError("Invalid Parquet page-index byte range") + data = source.read_at(length, offset) + if len(data) != length: + raise OSError("Truncated Parquet page-index byte range") + return data + + +def _read_index_ranges(source, ranges): + groups = [] + for key, offset, length in sorted(ranges, key=lambda item: item[1]): + if offset < 4 or length <= 0: + raise ValueError("Invalid Parquet page-index byte range") + end = offset + length + if groups and offset < groups[-1][1]: + raise ValueError("Overlapping Parquet page-index byte ranges") + if groups and offset == groups[-1][1]: + groups[-1][1] = end + groups[-1][2].append((key, offset, length)) + else: + groups.append([offset, end, [(key, offset, length)]]) + result = {} + for start, end, members in groups: + data = memoryview(_read_exact(source, start, end - start)) + for key, offset, length in members: + result[key] = data[offset - start:offset - start + length] + return result + + +class ParquetPageIndexReader: + def __init__(self, source, metadata, schema, footer, columns, fields, batch_size): + self.source = source + self.metadata = metadata + self.schema = schema + self.footer = footer + self.columns = columns + self.fields = fields + self.batch_size = batch_size + + @classmethod + def create(cls, source, parquet_file, columns, row_groups, batch_size): + metadata = parquet_file.metadata + schema = parquet_file.schema_arrow + if not columns or len(set(schema.names)) != len(schema): + return None + indices = [schema.get_field_index(name) for name in columns] + if any(index < 0 for index in indices) or len(set(indices)) != len(indices): + return None + if not any(getattr(metadata.row_group(group).column(index), + "has_offset_index", False) + for group in row_groups for index in range(metadata.num_columns)): + return None + if (metadata.serialized_size > _MAX_FOOTER_BYTES + or metadata.num_row_groups * metadata.num_columns + > _MAX_FOOTER_COLUMN_CHUNKS): + return None + output = pa.BufferOutputStream() + metadata.write_metadata_file(output) + serialized = output.getvalue().to_pybytes() + length = struct.unpack("<I", serialized[-8:-4])[0] + if length > _MAX_FOOTER_BYTES: + return None + footer = _Compact(serialized[-8 - length:-8]).value(12) + if 8 in footer or 9 in footer: + return None # Encrypted pages need the original file identity/AAD. + elements = _get(footer, 2)[1] + # Parquet stores a preorder schema tree and one chunk per physical leaf. + # Arrow field positions cannot be used as physical column positions. + fields = [] + position, leaf = 1, 0 + for _ in range(_get(elements[0], 5)): + start, first_leaf, pending = position, leaf, 1 + while pending: + if position >= len(elements): + raise ValueError("Truncated Parquet schema tree") + element = elements[position] + children = _get(element, 5, 0) + if children < 0 or (1 in element and children) or (1 not in element and not children): + raise ValueError("Invalid Parquet schema child count") + pending += children - 1 + leaf += int(1 in element) + position += 1 + fields.append((elements[start:position], list(range(first_leaf, leaf)))) + if (position != len(elements) or leaf != metadata.num_columns + or len(fields) != len(schema)): + return None + if not any(all(getattr(metadata.row_group(group).column(leaf), + "has_offset_index", False) + for index in indices for leaf in fields[index][1]) + for group in row_groups): + return None + return cls(source, metadata, schema, footer, indices, fields, batch_size) + + def read_row_group(self, group, runs): + """Return selected batches, or None when the ordinary reader is cheaper.""" + # Decide before reading indexes so scattered selections preserve the + # existing I/O pattern. A future multi-range path needs an I/O planner + # that accounts for filesystem prefetch, not just compressed page sizes. + if len(runs) != 1: + return None + row_group = _get(self.footer, 4)[1][group] + row_count = _get(row_group, 3) + if sum(upper - lower + 1 for lower, upper in runs) >= row_count: + return None + chunks = _get(row_group, 1)[1] + physical_columns = [leaf for index in self.columns for leaf in self.fields[index][1]] + if any(4 not in chunks[index] or 5 not in chunks[index] + or _get(chunks[index], 1) or 8 in chunks[index] or 9 in chunks[index] + or 10 in _get(chunks[index], 3) # Legacy index pages. + for index in physical_columns): + return None + indexed = {} + plans = [] + selected_bytes = 0 + full_bytes = 0 + index_ranges = [] + for index in sorted(physical_columns): + chunk = chunks[index] + index_size = _get(chunk, 5) + index_ranges.append((index, _get(chunk, 4), index_size)) + index_bytes = sum(length for _, _, length in index_ranges) + if index_bytes > _MAX_INDEX_BYTES: + return None + raw_indexes = _read_index_ranges(self.source, index_ranges) + remaining_locations = _MAX_PAGE_LOCATIONS + for index in sorted(physical_columns): + chunk = chunks[index] + try: + locations = _decode_offset_index(raw_indexes[index], remaining_locations) + except _PageIndexBudgetExceeded: + return None + remaining_locations -= len(locations) + column = _get(chunk, 3) + data_offset = _get(column, 9) + dictionary_offset = _get(column, 11, data_offset) + chunk_end = dictionary_offset + _get(column, 7) + starts = [page[2] for page in locations] + if not starts or starts[0] != 0 or starts[-1] >= row_count: + raise ValueError("Invalid Parquet OffsetIndex row boundaries") + previous_end = data_offset + previous_row = -1 + for page in locations: + offset, size, first_row = page + if (offset < previous_end or size <= 0 or offset + size > chunk_end + or first_row <= previous_row): + raise ValueError("Invalid Parquet OffsetIndex page location") + previous_end, previous_row = offset + size, first_row + if locations[0][0] != data_offset or dictionary_offset > data_offset: + raise ValueError("Invalid Parquet OffsetIndex first page") + indexed[index] = (column, dictionary_offset, data_offset - dictionary_offset, + locations, starts) + full_bytes += _get(column, 7) + for field in sorted(self.columns): + leaves = self.fields[field][1] + # OffsetIndex pages must start at row boundaries (repetition level 0). + # Keep all leaves of a field aligned so Arrow can reconstruct nesting. + # ponytail: common boundaries may widen to the whole group; independent + # leaf decoding/reassembly can recover savings if this becomes costly. + boundaries = set(indexed[leaves[0]][4]) + for leaf in leaves[1:]: + boundaries.intersection_update(indexed[leaf][4]) + boundaries = sorted(boundaries) + [row_count] + lower, upper = runs[0] + lower = boundaries[bisect.bisect_right(boundaries, lower) - 1] + end = boundaries[bisect.bisect_right(boundaries, upper)] + column_plans = [] + for index in leaves: + column, dictionary_offset, dictionary_size, locations, starts = indexed[index] + selected = range(bisect.bisect_left(starts, lower), + bisect.bisect_left(starts, end)) + pages, infos = [], [] + for position in selected: + page = locations[position] + pages.append(page[:2]) + next_row = starts[position + 1] if position + 1 < len(starts) else row_count + infos.append((starts[position], next_row - starts[position])) + selected_bytes += dictionary_size + sum(size for _, size in pages) + column_plans.append((index, column, dictionary_offset, dictionary_size, pages, infos)) + plans.append((field, column_plans, [(lower, end - lower)])) + if (selected_bytes + index_bytes >= full_bytes + or selected_bytes > _MAX_PAGE_BYTES): + return None + return self._batches(plans, runs) + + def _column_payload(self, plan): + index, column, dictionary_offset, dictionary_size, pages, infos = plan + ranges = ([(dictionary_offset, dictionary_size)] if dictionary_size else []) + pages + # Coalesce adjacent dictionary/data pages without fetching skipped pages. + groups = [] + for offset, length in ranges: + if groups and groups[-1][0] + groups[-1][1] == offset: + groups[-1][1] += length + else: + groups.append([offset, length]) + payload = b"".join(_read_exact(self.source, offset, length) + for offset, length in groups) + cursor = 0 + uncompressed_size = 0 + num_values = 0 + repeated = self.metadata.schema.column(index).max_repetition_level > 0 + for position, (_, length) in enumerate(ranges): + parser = _Compact(memoryview(payload)[cursor:cursor + length]) + header = parser.value(12) Review Comment: OffsetIndex has been switched to a typed/bounded decoder, but the PageHeader of the data page is still decoded using the generic `_Compact.value(12)`, which fully expands unknown collections or structs into Python lists or dictionaries. `_MAX_PAGE_BYTES` limits only the encoded data size (32 MiB), not the size of the decoded objects. -- This is an automated message from the Apache Git Service. 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