package lance.encodings_datafusion

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ZoneMaps are a way to wrap any leaf array with a set of zone maps that can be used to apply pushdown filtering. A "zone map" is the min/max/null_count of a set of rows. This can be used to quickly filter out zones which are not included in simple predicates like 'x = 5' or 'x > 10'.

• uint32 rows_per_map = 1

  How many rows are covered by each zone map. There will be ceil_div(num_rows, rows_per_map) zone maps.

• optional encodings.ArrayEncoding stats = 2

  The zone maps are encoded as struct arrays with 1 row per zone. This should be stored in a column metadata buffer. The struct array should have 3 children: min: T, max: T, null_count: u32

• optional encodings.ArrayEncoding values = 5

  The underlying array values