Expand description
Modules§
- error 🔒
- explain 🔒
EXPLAINsupport for structures defined in this crate. - expr 🔒This file houses a representation of a SQL plan that is parallel to that found in src/expr/relation/mod.rs, but represents an earlier phase of planning. It’s structurally very similar to that file, with some differences which are noted below. It gets turned into that representation via a call to lower().
- literal 🔒
- lowering 🔒Lowering is the process of transforming a
HirRelationExprinto aMirRelationExpr. - notice 🔒
- Helper code used throughout the planner.
- query 🔒SQL
Querys are the declarative, computational part of SQL. This module turnsQuerys intoHirRelationExprs - a more explicit, algebraic way of describing computation. Functions named plan_* are typically responsible for handling a single node of the SQL ast. Egplan_queryis responsible for handlingsqlparser::ast::Query. plan_* functions which correspond to operations on relations typically return aHirRelationExpr. plan_* functions which correspond to operations on scalars typically return aHirScalarExprand aScalarType. (The latter is because it’s not always possible to infer from aHirScalarExprwhat the intended type is - notably in the case of decimals where the scale/precision are encoded only in the type). Aggregates are particularly twisty. - scope 🔒Handles SQL’s scoping rules.
- Support for side-effecting functions.
- Statement planning.
- Transformations of SQL ASTs.
- Transformations of SQL IR, before decorrelation.
- typeconv 🔒Maintains a catalog of valid casts between
mz_repr::ScalarTypes, as well as other cast-related functions. - Provides tooling to handle
WITHoptions.
Structs§
- Generated by
ALTER ... IF EXISTSif the named object did not exist. - Configuration of introspection for a cluster replica.
- A
CreateSourcePlanand the metadata necessary to sequence it. - A bundle of unrelated things that we need for planning
Exprs. - A vector of values to which parameter references should be bound.
- Controls planning of a SQL query.
- The state required when planning a
Query. - A plan for select statements.
- An available external reference for a source and if possible to retrieve, any column names it contains.
- Immutable state that applies to the planning of an entire
Statement. - Describes the output of a SQL statement.
Enums§
- A
CoercibleScalarExpris aHirScalarExprwhose type is not fully determined. Several SQL expressions can be freely coerced based upon where in the expression tree they appear. For example, the string literal ‘42’ will be automatically coerced to the integer 42 if used in a numeric context: - The type of object to be explained
- Explainee types that are statements.
- Just like
mz_expr::MirRelationExpr, except where otherwise noted below. - Just like
mz_expr::MirScalarExpr, except where otherwise noted below. - Instructions for executing a SQL query.
- Notices that can occur in the adapter layer.
- Specifies how long a query will live.
- Specifies when a
PeekorSubscribeshould occur. - A side-effecting function is a function whose evaluation triggers side effects.
- Statement classification as documented by
plan. - A window function with its parameters.
Functions§
- Creates a description of the purified statement
stmt. - Normalize the way subqueries appear in
HirScalarExpr::ExistsorHirScalarExpr::Selectvariants. - Produces a
Planfrom the purified statementstmt.