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doris/fe
924060929 321bb3e9ee [refactor](Nereids) Refactor and optimize partition pruning (#18003)
the legacy PartitionPruner only support some simple cases, some useful cases not support:
1. can not support evaluate some builtin functions, like `cast(part_column as bigint) = 1`
2. can not prune multi level range partition, for partition `[[('1', 'a'), ('2', 'b'))`, it has some constraints:
    - first_part_column between '1' and '2'
    - if first_part_column = '1' then second_part_column >= 'a'
    - if first_part_column = '2' then second_part_column < 'a'

This pr refactor it and support:
1. use visitor to evaluate function and fold constant
2. if the partition is discrete like int, date, we can expand it and evaluate, e.g `[1, 5)` will be expand to `[1, 2, 3, 4]`
3. support prune multi level range partition, as previously described
4. support evaluate capabilities for a range slot, e.g. datetime range partition `[('2023-03-21 00:00:00'), ('2023-03-21 23:59:59'))`,  if the filter is `date(col1) = '2023-03-22'`, this partition will be pruned, we can do this prune because we know that the date always is `2023-03-21`. you can implement the visit method in FoldConstantRuleOnFE and OneRangePartitionEvaluator to support this functions.

### How can we do it so finely ?
Generally, the range partition can separate to three parts: `const`, `range`, `other`.
for example,  the partition `[(1, 'a', 'D'), ('1', 'c', 'D'))` exist
1. first partition column is `const`: always equals to '1'
2. second partition column is `range`: `slot >= 'a' and <= 'c'`. If not later slot, it must be `slot >= 'a' and < 'c'`
3. third partition column is `other`: regardless of whether the upper and lower bounds are the same, it must exist multi values, e.g. `('1', 'a', 'D')`, `('1', 'a', 'F')`, `('1', 'b', 'A')`, `('1', 'c', 'A')` 

In a partition, there is one and only one `range` slot can exist; maybe zero or one or many `const`/`other` slots.
Normally, a partition look like [const*, range, other*], these are the possible shapes:
1. [range], e.g `[('1'), ('10'))`
2. [const, range], e.g. `[('1', 'a'), ('1', 'd'))`
3. [range, other, other], e.g. `[('1', '1', '1'), ('2', '1', '1'))`
4. [const, const, ..., range, other, other, ...], e.g. `[('1', '1', '2', '3', '4'), ('1', '1', '3', '3', '4'))`

The properties of `const`: 
1. we can replace slot to literal to evaluate expression tree.

The properties of `range`:
1. if the slot date type is discrete type, like int, and date, we can expand it to literal and evaluate expression tree
2. if not discrete type, like datetime, or the discrete values too much, like [1, 1000000), we can keep the slot in the expression tree, and assign a range for it, when evaluate expression tree, we also compute the range and check whether range is empty set, if so we can simplify to BooleanLiteral.FALSE to skip this partition.
5. if the range slot satisfied some conditions , we can fold the slot with some function too, see the datetime example above

The properties of `other`:
1. only when the previous slot is literal and equals to the lower bound or upper bound of partition, we can shrink the range of the `other` slot

According this properties, we can do it finely.


at the runtime, the `range` and `other` slot maybe shrink the range of values,
e.g.
1. the partition `[('a'), ('b'))` with predicate `part_col = 'a'` will shrink range `['a', 'b')` to `['a']`, like a `range` slot change/downgrading to `const` slot;
2. the partition `[('a', '1'), ('b', '10'))` with predicate `part_col1 = 'a'` will shrink the range of `other` slot from unknown(all range) to `['1', +∞)`, like a `other` slot change/downgrading to `range` slot.

But to simplify, I haven't change the type at the runtime, just shrink the ColumnRange.
2023-03-24 09:06:52 +08:00
..

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# fe-common

This module is used to store some common classes of other modules.

# spark-dpp

This module is Spark DPP program, used for Spark Load function.
Depends: fe-common

# fe-core

This module is the main process module of FE.
Depends: fe-common, spark-dpp