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

id 🔒

interpret 🔒

like_pattern

linear 🔒

relation 🔒

row

scalar 🔒

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

AnalyzedRegexOpts

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.

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.

JoinInputCharacteristics

Characteristics of a join order candidate collection.

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

order_aggregate_datums_exported_for_benchmarking

Assuming datums is a List, sort them by the 2nd through Nth elements corresponding to order_by, then return the 1st element.

permutation_for_arrangement

Derive supporting logic to support transforming rows to (key, val) pairs, and back again.