[enhancement](parquet)Optimize the performance of parquet reader when decode RLE_DICTIONARY encoding#57208
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morningman merged 3 commits intoapache:masterfrom Oct 31, 2025
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… decode RLE_DICTIONARY encoding (#57208) ### What problem does this PR solve? Problem Summary: When parsing RLE_DICTIONARY encoding, the parquet reader uniformly uses memcpy. However, for INT32, INT64, etc., direct assignment is faster than memcpy. In Parquet dictionary encoding, the actual data is not stored contiguously, resulting in very small memcpy sizes. When analyzing the implementation of `memcpy`, we can see that for such small sizes, `__builtin_memcpy` is used instead. The implementation of `__builtin_memcpy` essentially behaves like a series of simple assignments. You can observe the corresponding assembly code here: https://godbolt.org/z/r9Ma1ozvd.
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Oct 31, 2025
… decode RLE_DICTIONARY encoding (apache#57208) ### What problem does this PR solve? Problem Summary: When parsing RLE_DICTIONARY encoding, the parquet reader uniformly uses memcpy. However, for INT32, INT64, etc., direct assignment is faster than memcpy. In Parquet dictionary encoding, the actual data is not stored contiguously, resulting in very small memcpy sizes. When analyzing the implementation of `memcpy`, we can see that for such small sizes, `__builtin_memcpy` is used instead. The implementation of `__builtin_memcpy` essentially behaves like a series of simple assignments. You can observe the corresponding assembly code here: https://godbolt.org/z/r9Ma1ozvd.
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… decode RLE_DICTIONARY encoding (apache#57208) Problem Summary: When parsing RLE_DICTIONARY encoding, the parquet reader uniformly uses memcpy. However, for INT32, INT64, etc., direct assignment is faster than memcpy. In Parquet dictionary encoding, the actual data is not stored contiguously, resulting in very small memcpy sizes. When analyzing the implementation of `memcpy`, we can see that for such small sizes, `__builtin_memcpy` is used instead. The implementation of `__builtin_memcpy` essentially behaves like a series of simple assignments. You can observe the corresponding assembly code here: https://godbolt.org/z/r9Ma1ozvd.
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What problem does this PR solve?
Problem Summary:
When parsing RLE_DICTIONARY encoding, the parquet reader uniformly uses memcpy. However, for INT32, INT64, etc., direct assignment is faster than memcpy.
In Parquet dictionary encoding, the actual data is not stored contiguously, resulting in very small memcpy sizes. When analyzing the implementation of
memcpy, we can see that for such small sizes,__builtin_memcpyis used instead. The implementation of__builtin_memcpyessentially behaves like a series of simple assignments. You can observe the corresponding assembly code here: https://godbolt.org/z/r9Ma1ozvd.Release note
None
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