polars.LazyFrame.explain#

LazyFrame.explain(
*,
format: ExplainFormat = 'plain',
optimized: bool = True,
type_coercion: bool = True,
predicate_pushdown: bool = True,
projection_pushdown: bool = True,
simplify_expression: bool = True,
slice_pushdown: bool = True,
comm_subplan_elim: bool = True,
comm_subexpr_elim: bool = True,
cluster_with_columns: bool = True,
collapse_joins: bool = True,
streaming: bool = False,
tree_format: bool | None = None,
) str[source]#

Create a string representation of the query plan.

Different optimizations can be turned on or off.

Parameters:
format{‘plain’, ‘tree’}

The format to use for displaying the logical plan.

optimized

Return an optimized query plan. Defaults to True. If this is set to True the subsequent optimization flags control which optimizations run.

type_coercion

Do type coercion optimization.

predicate_pushdown

Do predicate pushdown optimization.

projection_pushdown

Do projection pushdown optimization.

simplify_expression

Run simplify expressions optimization.

slice_pushdown

Slice pushdown optimization.

comm_subplan_elim

Will try to cache branching subplans that occur on self-joins or unions.

comm_subexpr_elim

Common subexpressions will be cached and reused.

cluster_with_columns

Combine sequential independent calls to with_columns

collapse_joins

Collapse a join and filters into a faster join

streaming

Run parts of the query in a streaming fashion (this is in an alpha state)

Warning

Streaming mode is considered unstable. It may be changed at any point without it being considered a breaking change.

tree_format

Format the output as a tree.

Deprecated since version 0.20.30: Use format="tree" instead.

Examples

>>> lf = pl.LazyFrame(
...     {
...         "a": ["a", "b", "a", "b", "b", "c"],
...         "b": [1, 2, 3, 4, 5, 6],
...         "c": [6, 5, 4, 3, 2, 1],
...     }
... )
>>> lf.group_by("a", maintain_order=True).agg(pl.all().sum()).sort(
...     "a"
... ).explain()