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perf: reading rows for many nearby but non-contiguous row indices decodes the same chunk repetitively #4940

@niyue

Description

@niyue

Description

When miniblock encoding is used in a Lance file, reading the file with the v2 FileReader via the read_stream_projected API can become inefficient if the provided ReadBatchParams::Indices contains many nearby but non-contiguous row indices.

For example:

29, 168, 180, 194, 376, 559, 574, 665, 666, 667, ..., 968, 969, 970, 973, 975, ...

This kind of access pattern causes the same chunk to be decoded repeatedly, resulting in slow performance and high CPU usage.

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