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