Crate datafusion_optimizer

DataFusion Optimizer

Contains rules for rewriting LogicalPlans

1. Analyzer applies AnalyzerRules to transform LogicalPlans to make the plan valid prior to the rest of the DataFusion optimization process (for example, TypeCoercion).

2. Optimizer applies OptimizerRules to transform LogicalPlans into equivalent, but more efficient plans.

Re-exports

• pub use analyzer::Analyzer;
• pub use analyzer::AnalyzerRule;
• pub use optimizer::Optimizer;
• pub use optimizer::OptimizerConfig;
• pub use optimizer::OptimizerContext;
• pub use optimizer::OptimizerRule;
• pub use utils::optimize_children;

Modules

• analyzer
  Analyzer and AnalyzerRule
• common_subexpr_eliminate
  CommonSubexprEliminate to avoid redundant computation of common sub-expressions
• decorrelate
  PullUpCorrelatedExpr converts correlated subqueries to Joins
• decorrelate_predicate_subquery
  DecorrelatePredicateSubquery converts IN/EXISTS subquery predicates to SEMI/ANTI joins
• eliminate_cross_join
  EliminateCrossJoin converts CROSS JOIN to INNER JOIN if join predicates are available.
• eliminate_duplicated_expr
  EliminateDuplicatedExpr Removes redundant expressions
• eliminate_filter
  EliminateFilter replaces where false or where null with an empty relation.
• eliminate_join
  EliminateJoin rewrites INNER JOIN with true/null
• eliminate_limit
  EliminateLimit eliminates LIMIT when possible
• eliminate_nested_union
  EliminateNestedUnion: flattens nested Union to a single Union
• eliminate_one_union
  EliminateOneUnion eliminates single element Union
• eliminate_outer_join
  EliminateOuterJoin converts LEFT/RIGHT/FULL joins to INNER joins
• extract_equijoin_predicate
  ExtractEquijoinPredicate identifies equality join (equijoin) predicates
• filter_null_join_keys
  FilterNullJoinKeys adds filters to join inputs when input isn’t nullable
• optimize_projections
  OptimizeProjections identifies and eliminates unused columns
• optimizer
  Optimizer and OptimizerRule
• propagate_empty_relation
  PropagateEmptyRelation eliminates nodes fed by EmptyRelation
• push_down_filter
  PushDownFilter applies filters as early as possible
• push_down_limit
  PushDownLimit pushes LIMIT earlier in the query plan
• replace_distinct_aggregate
  ReplaceDistinctWithAggregate replaces DISTINCT ... with GROUP BY ...
• rewrite_disjunctive_predicate
  RewriteDisjunctivePredicate rewrites predicates to reduce redundancy
• scalar_subquery_to_join
  ScalarSubqueryToJoin rewriting scalar subquery filters to JOINs
• simplify_expressions
  SimplifyExpressions simplifies expressions in the logical plan, ExprSimplifier simplifies individual Exprs.
• single_distinct_to_groupby
  SingleDistinctToGroupBy replaces AGG(DISTINCT ..) with AGG(..) GROUP BY ..
• unwrap_cast_in_comparison
  UnwrapCastInComparison rewrites CAST(col) = lit to col = CAST(lit)
• utils
  Utility functions leveraged by the query optimizer rules