sqlglot.optimizer.optimizer

 1from __future__ import annotations
 2
 3import typing as t
 4
 5import sqlglot
 6from sqlglot import Schema, exp
 7from sqlglot.dialects.dialect import DialectType
 8from sqlglot.optimizer.annotate_types import annotate_types
 9from sqlglot.optimizer.canonicalize import canonicalize
10from sqlglot.optimizer.eliminate_ctes import eliminate_ctes
11from sqlglot.optimizer.eliminate_joins import eliminate_joins
12from sqlglot.optimizer.eliminate_subqueries import eliminate_subqueries
13from sqlglot.optimizer.expand_multi_table_selects import expand_multi_table_selects
14from sqlglot.optimizer.isolate_table_selects import isolate_table_selects
15from sqlglot.optimizer.lower_identities import lower_identities
16from sqlglot.optimizer.merge_subqueries import merge_subqueries
17from sqlglot.optimizer.normalize import normalize
18from sqlglot.optimizer.optimize_joins import optimize_joins
19from sqlglot.optimizer.pushdown_predicates import pushdown_predicates
20from sqlglot.optimizer.pushdown_projections import pushdown_projections
21from sqlglot.optimizer.qualify_columns import qualify_columns, validate_qualify_columns
22from sqlglot.optimizer.qualify_tables import qualify_tables
23from sqlglot.optimizer.simplify import simplify
24from sqlglot.optimizer.unnest_subqueries import unnest_subqueries
25from sqlglot.schema import ensure_schema
26
27RULES = (
28    lower_identities,
29    qualify_tables,
30    isolate_table_selects,
31    qualify_columns,
32    pushdown_projections,
33    validate_qualify_columns,
34    normalize,
35    unnest_subqueries,
36    expand_multi_table_selects,
37    pushdown_predicates,
38    optimize_joins,
39    eliminate_subqueries,
40    merge_subqueries,
41    eliminate_joins,
42    eliminate_ctes,
43    annotate_types,
44    canonicalize,
45    simplify,
46)
47
48
49def optimize(
50    expression: str | exp.Expression,
51    schema: t.Optional[dict | Schema] = None,
52    db: t.Optional[str] = None,
53    catalog: t.Optional[str] = None,
54    dialect: DialectType = None,
55    rules: t.Sequence[t.Callable] = RULES,
56    **kwargs,
57):
58    """
59    Rewrite a sqlglot AST into an optimized form.
60
61    Args:
62        expression: expression to optimize
63        schema: database schema.
64            This can either be an instance of `sqlglot.optimizer.Schema` or a mapping in one of
65            the following forms:
66                1. {table: {col: type}}
67                2. {db: {table: {col: type}}}
68                3. {catalog: {db: {table: {col: type}}}}
69            If no schema is provided then the default schema defined at `sqlgot.schema` will be used
70        db: specify the default database, as might be set by a `USE DATABASE db` statement
71        catalog: specify the default catalog, as might be set by a `USE CATALOG c` statement
72        dialect: The dialect to parse the sql string.
73        rules: sequence of optimizer rules to use.
74            Many of the rules require tables and columns to be qualified.
75            Do not remove qualify_tables or qualify_columns from the sequence of rules unless you know
76            what you're doing!
77        **kwargs: If a rule has a keyword argument with a same name in **kwargs, it will be passed in.
78    Returns:
79        sqlglot.Expression: optimized expression
80    """
81    schema = ensure_schema(schema or sqlglot.schema, dialect=dialect)
82    possible_kwargs = {"db": db, "catalog": catalog, "schema": schema, **kwargs}
83    expression = exp.maybe_parse(expression, dialect=dialect, copy=True)
84    for rule in rules:
85        # Find any additional rule parameters, beyond `expression`
86        rule_params = rule.__code__.co_varnames
87        rule_kwargs = {
88            param: possible_kwargs[param] for param in rule_params if param in possible_kwargs
89        }
90        expression = rule(expression, **rule_kwargs)
91    return expression