Trait ColIndexMappingRewriteExt

pub trait ColIndexMappingRewriteExt {
    // Required methods
    fn rewrite_provided_order(&self, _: &Order) -> Order;
    fn rewrite_required_order(&self, _: &Order) -> Option<Order>;
    fn rewrite_dist_key(&self, _: &[usize]) -> Option<Vec<usize>>;
    fn rewrite_provided_distribution(&self, _: &Distribution) -> Distribution;
    fn rewrite_required_distribution(&self, _: &RequiredDist) -> RequiredDist;
    fn rewrite_functional_dependency(
        &self,
        _: &FunctionalDependency,
    ) -> Option<FunctionalDependency>;
    fn rewrite_functional_dependency_set(
        &self,
        _: FunctionalDependencySet,
    ) -> FunctionalDependencySet;
    fn rewrite_bitset(&self, _: &FixedBitSet) -> FixedBitSet;
    fn rewrite_monotonicity_map(&self, _: &MonotonicityMap) -> MonotonicityMap;
}

Extension trait for ColIndexMapping to rewrite frontend structures.

Required Methods

fn rewrite_provided_order(&self, _: &Order) -> Order

Rewrite the provided order’s column index. It will try its best to give the most accurate order. Order(0,1,2) with mapping(0->1,1->0,2->2) will be rewritten to Order(1,0,2) Order(0,1,2) with mapping(0->1,2->0) will be rewritten to Order(1)

fn rewrite_required_order(&self, _: &Order) -> Option<Order>

Rewrite the required order’s field index. if it can’t give a corresponding required order after the column index mapping, it will return None. Order(0,1,2) with mapping(0->1,1->0,2->2) will be rewritten to Order(1,0,2) Order(0,1,2) with mapping(0->1,2->0) will return None

fn rewrite_dist_key(&self, _: &[usize]) -> Option<Vec<usize>>

Rewrite the distribution key and will return None if any index of the key disappear after the mapping.

fn rewrite_provided_distribution(&self, _: &Distribution) -> Distribution

Rewrite the provided distribution’s field index. It will try its best to give the most accurate distribution. HashShard(0,1,2), with mapping(0->1,1->0,2->2) will be rewritten to HashShard(1,0,2). HashShard(0,1,2), with mapping(0->1,2->0) will be rewritten to SomeShard.

fn rewrite_required_distribution(&self, _: &RequiredDist) -> RequiredDist

Rewrite the required distribution’s field index. if it can’t give a corresponding required distribution after the column index mapping, it will return None. ShardByKey(0,1,2), with mapping(0->1,1->0,2->2) will be rewritten to ShardByKey(1,0,2). ShardByKey(0,1,2), with mapping(0->1,2->0) will return ShardByKey(1,0). ShardByKey(0,1), with mapping(2->0) will return Any.

fn rewrite_functional_dependency( &self, _: &FunctionalDependency, ) -> Option<FunctionalDependency>

Rewrite the indices in a functional dependency.

If some columns in the from side are removed, then this fd is no longer valid. For example, for ABC –> D, it means that A, B, and C together can determine C. But if B is removed, this fd is not valid. For this case, we will return None

Additionally, If the to side of a functional dependency becomes empty after rewriting, it means that this dependency is unneeded so we also return None.

fn rewrite_functional_dependency_set( &self, _: FunctionalDependencySet, ) -> FunctionalDependencySet

Rewrite functional dependencies in fd_set one by one, using [ColIndexMapping::rewrite_functional_dependency].

Note that this rewrite process handles each function dependency independently. Relationships within function dependencies are not considered. For example, if we have fd_set { AB –> C, A –> B }, and column B is removed. The result would be an empty fd_set, rather than { A –> C }.

fn rewrite_bitset(&self, _: &FixedBitSet) -> FixedBitSet

fn rewrite_monotonicity_map(&self, _: &MonotonicityMap) -> MonotonicityMap

Implementors

impl ColIndexMappingRewriteExt for ColIndexMapping