lidavidm commented on a change in pull request #6744:
URL: https://github.com/apache/arrow/pull/6744#discussion_r413757274
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File path: cpp/src/parquet/file_reader.cc
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@@ -212,6 +237,21 @@ class SerializedFile : public ParquetFileReader::Contents {
file_metadata_ = std::move(metadata);
}
+ void PreBuffer(const std::vector<int>& row_groups,
+ const std::vector<int>& column_indices,
+ const ::arrow::io::CacheOptions& options) {
+ cached_source_ =
+ std::make_shared<arrow::io::internal::ReadRangeCache>(source_,
options);
Review comment:
It depends: reading multiple row groups at once might cache chunks that
span row groups (and in general you want more opportunities to coalesce reads
if you are aiming for throughput). For more control over that, a consumer could
make repeated calls to `FileReader->RowGroup` to get individual RowGroupReaders
that would cache only a single RowGroup.
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