polyglot_sql/optimizer/
mod.rs

1//! SQL Optimizer Module
2//!
3//! This module contains optimization passes for SQL AST transformation,
4//! including type annotation, column qualification, and other semantic analysis.
5
6/// Type annotation and coercion for SQL expressions
7pub mod annotate_types;
8/// Canonicalization of SQL expressions into standard form
9pub mod canonicalize;
10/// Elimination of unused Common Table Expressions
11pub mod eliminate_ctes;
12/// Elimination of unused JOIN operations
13pub mod eliminate_joins;
14/// Isolation of table references into subqueries
15pub mod isolate_table_selects;
16/// Boolean expression normalization (CNF/DNF)
17pub mod normalize;
18/// Identifier case and quoting normalization
19pub mod normalize_identifiers;
20/// JOIN reordering and cross-join optimization
21pub mod optimize_joins;
22/// Main optimizer entry point and rule orchestration
23pub mod optimizer;
24/// Predicate pushdown into subqueries and JOINs
25pub mod pushdown_predicates;
26/// Projection pushdown to eliminate unused columns
27pub mod pushdown_projections;
28/// Column qualification and star expansion
29pub mod qualify_columns;
30/// Table reference qualification with catalog and schema
31pub mod qualify_tables;
32/// Boolean and algebraic expression simplification
33pub mod simplify;
34/// Subquery merging and unnesting
35pub mod subquery;
36
37/// Type annotation, type coercion classes, and the type annotator engine
38pub use annotate_types::{annotate_types, TypeAnnotator, TypeCoercionClass};
39/// Canonicalization of SQL expressions
40pub use canonicalize::canonicalize;
41/// CTE elimination and reference checking
42pub use eliminate_ctes::{eliminate_ctes, is_cte_referenced};
43/// JOIN elimination for unused joins
44pub use eliminate_joins::eliminate_joins;
45/// Table select isolation into subqueries
46pub use isolate_table_selects::isolate_table_selects;
47/// Boolean normalization, distance computation, and related utilities
48pub use normalize::{
49    normalization_distance, normalize, normalized, NormalizeError, DEFAULT_MAX_DISTANCE,
50};
51/// Identifier normalization, case sensitivity detection, and strategy types
52pub use normalize_identifiers::{
53    get_normalization_strategy, is_case_sensitive, normalize_identifier, normalize_identifiers,
54    NormalizationStrategy,
55};
56/// JOIN optimization, reordering, normalization, and reorderability checks
57pub use optimize_joins::{is_reorderable, normalize_joins, optimize_joins, reorder_joins};
58/// Full optimizer pipeline, rule configuration, and quick optimization
59pub use optimizer::{
60    optimize, optimize_with_rules, quick_optimize, OptimizationRule, OptimizerConfig, DEFAULT_RULES,
61};
62/// Predicate pushdown and alias replacement
63pub use pushdown_predicates::{pushdown_predicates, replace_aliases};
64/// Projection pushdown and default column selection
65pub use pushdown_projections::{default_selection, pushdown_projections};
66/// Column qualification, validation, output handling, and identifier quoting
67pub use qualify_columns::{
68    qualify_columns, qualify_outputs, quote_identifiers, validate_qualify_columns,
69    QualifyColumnsError, QualifyColumnsOptions,
70};
71/// Table qualification with catalog and schema defaults
72pub use qualify_tables::{qualify_tables, QualifyTablesOptions};
73/// Expression simplification, constant evaluation, and truthiness checks
74pub use simplify::{always_false, always_true, is_false, is_null, is_zero, simplify, Simplifier};
75/// Subquery merging, unnesting, and correlation analysis
76pub use subquery::{is_correlated, is_mergeable, merge_subqueries, unnest_subqueries};
77
78/// Structural identity for optimizer keys, independent of source metadata.
79/// Unlike generated SQL this also works in builds without the `generate` feature.
80fn structural_identity_key(expr: &crate::expressions::Expression) -> String {
81    fn remove_spans(value: &mut serde_json::Value) {
82        match value {
83            serde_json::Value::Object(fields) => {
84                fields.remove("span");
85                for value in fields.values_mut() {
86                    remove_spans(value);
87                }
88            }
89            serde_json::Value::Array(values) => {
90                for value in values {
91                    remove_spans(value);
92                }
93            }
94            _ => {}
95        }
96    }
97    let mut value = serde_json::to_value(expr).expect("expression serializes");
98    remove_spans(&mut value);
99    value.to_string()
100}
101
102/// Qualify a schema-aware expression without changing physical table aliases.
103///
104/// Anonymous derived tables need stable aliases before column qualification so
105/// their projected columns can be registered in the scoped schema. Physical
106/// table names and set-operation structure are otherwise left unchanged.
107pub(crate) fn qualify_schema_aware_expression(
108    expression: crate::expressions::Expression,
109    schema: &dyn crate::schema::Schema,
110    dialect: Option<crate::dialects::DialectType>,
111) -> Result<crate::expressions::Expression, QualifyColumnsError> {
112    let effective_dialect = dialect.or_else(|| schema.dialect());
113    let mut table_options = QualifyTablesOptions::new()
114        .with_alias_unaliased_tables(false)
115        .with_alias_unaliased_subqueries(true)
116        .with_normalize_set_operation_subqueries(false);
117    let mut column_options = QualifyColumnsOptions::new().with_allow_partial(true);
118
119    if let Some(dialect) = effective_dialect {
120        table_options = table_options.with_dialect(dialect);
121        column_options = column_options.with_dialect(dialect);
122    }
123
124    let expression = qualify_tables(expression, &table_options);
125    qualify_columns(expression, schema, &column_options)
126}
polyglot_sql/optimizer/mod.rs

polyglot_sql/optimizer/
mod.rs
