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Optimize BaseRelation.matches() #6844

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Optimize BaseRelation.matches() #6844

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39 changes: 13 additions & 26 deletions core/dbt/adapters/base/relation.py
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,6 @@
Path,
)
from dbt.exceptions import (
ApproximateMatchError,
DbtInternalError,
MultipleDatabasesNotAllowedError,
)
Expand Down Expand Up @@ -77,36 +76,24 @@ def matches(
schema: Optional[str] = None,
identifier: Optional[str] = None,
) -> bool:
search = filter_null_values(
{
ComponentName.Database: database,
ComponentName.Schema: schema,
ComponentName.Identifier: identifier,
}
)

if not search:
# nothing was passed in
raise dbt.exceptions.DbtRuntimeError(
"Tried to match relation, but no search path was passed!"
)
if identifier is not None and not self._is_exactish_match(
ComponentName.Identifier, identifier
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I like the way it was originally written. I think the performance pickup comes from two places:

  1. not looking for the approximate match
  2. not exiting the for loop once a match was found
    I think it could look something like this:
if not any(identifier, schema, database):
    raise dbt.exceptions.DbtRuntimeError(...)

search = filter_null_values(
    {
        ComponentName.Identifier: identifier,
        ComponentName.Schema: schema,
        ComponentName.Database: database
    }
)

return any(
    (
        self._is_exactish_match(existing_components, new_component)
        for existing_components, new_component in search.items()
    )
)

I'm pretty sure any() will lazily evaluate each element in the generator and then stop when it finds one, which is what you're trying to do.

):
return False

exact_match = True
approximate_match = True
if schema is not None and not self._is_exactish_match(ComponentName.Schema, schema):
return False

for k, v in search.items():
if not self._is_exactish_match(k, v):
exact_match = False
if str(self.path.get_lowered_part(k)).strip(self.quote_character) != v.lower().strip(
self.quote_character
):
approximate_match = False # type: ignore[union-attr]
if database is not None and not self._is_exactish_match(ComponentName.Database, database):
return False

if approximate_match and not exact_match:
target = self.create(database=database, schema=schema, identifier=identifier)
raise ApproximateMatchError(target, self)
if database is None and schema is None and identifier is None:
raise dbt.exceptions.DbtRuntimeError(
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I would put this first since you don't need to run self._is_exactish_match(). I'm assuming that method is the expensive method. I'd also rephrase the if clause:

if not any(database, schema, identifier):
    raise dbt.exceptions.DbtRuntimeError(...)

"Tried to match relation, but no search path was passed!"
)

return exact_match
return True

def replace_path(self, **kwargs):
return self.replace(path=self.path.replace(**kwargs))
Expand Down