Crate mz_expr

Core expression language.

Modules

• canonicalize
  Utility functions to transform parts of a single MirRelationExpr into canonical form.
• explain
  EXPLAIN support for structures defined in this crate.
• func
• like_pattern
• refresh_schedule
• virtual_syntax
  A set of virtual nodes that are used to recover some high-level concepts that are desugared to non-trival terms in some IRs.
• visit
  Visitor support for recursive data types.

Structs

• AggregateExpr
  Describes an aggregation expression.
• AnalyzedRegex
• CaptureGroupDesc
• ColumnOrder
  Specification for an ordering by a column.
• ColumnSpec
• ColumnSpecs
  An interpreter that:
• FilterCharacteristics
  Filter characteristics that are used for ordering join inputs. This can be created for a Vec<MirScalarExpr>, which represents an AND of predicates.
• JoinInputCharacteristics
  Characteristics of a join order candidate collection.
• JoinInputMapper
  Any column in a join expression exists in two contexts:
• LetRecLimit
  Maximum iterations for a LetRec.
• LocalId
  The identifier for a local component of a dataflow.
• MapFilterProject
  A compound operator that can be applied row-by-row.
• MfpPlan
  Predicates partitioned into temporal and non-temporal.
• NaiveOneByOneAggr
  Naive implementation of OneByOneAggr, suitable for stuff like const folding, but too slow for rendering. This relies only on infrastructure available in mz-expr. It simply saves all the given input, and calls the given AggregateFunc’s eval method when asked about the current aggregate. (For Accumulable and Hierarchical aggregations, the rendering has more efficient implementations, but for Basic aggregations even the rendering uses this naive implementation.)
• OptimizedMirRelationExpr
  A MirRelationExpr that claims to have been optimized, e.g., by an transform::Optimizer.
• ProtoAggregateExpr
• ProtoAggregateFunc
• ProtoColumnOrder
• ProtoDomainLimit
• ProtoEvalError
• ProtoId
• ProtoLocalId
• ProtoMapFilterProject
• ProtoMfpPlan
• ProtoMirScalarExpr
• ProtoRowSetFinishing
• ProtoSafeMfpPlan
• ProtoTableFunc
• ResultSpec
  An approximation of the set of values an expression might have, including whether or not it might be null or an error value. This is generally an overapproximation, in the sense that ResultSpec::may_contain may return true even if the argument is not included in the set. (However, it should never return false when the value is included!)
• RowSetFinishing
  Instructions for finishing the result of a query.
• SafeMfpPlan
  A wrapper type which indicates it is safe to simply evaluate all expressions.
• SourceInstanceId
  Unique identifier for an instantiation of a source.
• Trace
  An interpreter that returns whether or not a particular expression is “pushdownable”. Broadly speaking, an expression is pushdownable if the result of evaluating the expression depends on the range of possible column values in a way that ColumnSpecs is able to reason about.
• WindowFrame
  Describe a window frame, e.g. RANGE UNBOUNDED PRECEDING or ROWS BETWEEN 5 PRECEDING AND CURRENT ROW.

Enums

• AccessStrategy
  For a global Get, this indicates whether we are going to read from Persist or from an index. (See comment in MirRelationExpr::Get.)
• AggregateFunc
• BinaryFunc
• EvalError
• Id
  An opaque identifier for a dataflow component. In other words, identifies the target of a MirRelationExpr::Get.
• JoinImplementation
  Describe a join implementation in dataflow.
• LagLeadType
  Identify whether the given aggregate function is Lag or Lead, since they share implementations.
• MirRelationExpr
  An abstract syntax tree which defines a collection.
• MirScalarExpr
• TableFunc
• TraceSummary
  A summary type for the Trace interpreter.
• UnaryFunc
• UnmaterializableFunc
• VariadicFunc
• WindowFrameBound
  Specifies WindowFrame’s start_bound and end_bound
• WindowFrameUnits
  Describe how frame bounds are interpreted

Constants

• RECURSION_LIMIT
  A recursion limit to be used for stack-safe traversals of MirRelationExpr trees.

Traits

• CollectionPlan
  A trait for types that describe how to build a collection.
• Interpreter
  Abstract interpretation for MirScalarExpr.
• OneByOneAggr
  An implementation of an aggregation where we can send in the input elements one-by-one, and can also ask the current aggregate at any moment. (This just delegates to other aggregation evaluation approaches.)

Functions

• compare_columns
  Compare left and right using order. If that doesn’t produce a strict ordering, call tiebreaker.
• join_permutations
  Given the permutations (see permutation_for_arrangement and (dataflow::plan::AvailableCollections) corresponding to two collections with the same key arity, computes the permutation for the result of joining them.
• memoize_expr
  Recursively memoize parts of expr, storing those parts in memoized_parts.
• non_nullable_columns
  Augment non-nullability of columns, by observing either
• permutation_for_arrangement
  Return the map associating columns in the logical, unthinned representation of a collection to columns in the thinned representation of the arrangement corresponding to key.