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Turning on the long mode with a small window size (=10) did not help in both size and speed; as the compression level increased, the compression ratio also improved but, they had a small gain of size compared with zstd / level=1 / window=0 (less than 10%) with being overwhelmingly slow. If the smaller compressed size is necessary at the cost of the speed with zstd / level = 1 fixed, enlarging the window size to 22 would be a good approach - it takes twice compressing time but is still much faster than the other configurations.

Conclusion

In general, lowering the level and making the buffer/block/window size enough to the given data size resulted in the most satisfactory result. This result agrees with the randomly generated dataset-based result and the producer/consumer benchmark conducted in KIP-390 - which recommended lower the compression level to boost the producing speed.

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Since the default values of newly introduced options are all identical to the currently used values, there are no compatibility or migration issues.

Rejected Alternatives

Recompression is enabled even when the detailed codec configuration is different

To enable this feature, we have to store the detailed compression configuration into the record batch. (currently, only the codec is stored.) It requires the modification of the record batch's binary format.

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