Skip to content

Improve lookml sql derived tables detection, add cascading derived tables to lineage #2770

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
shirshanka merged 2 commits into from
Jun 30, 2021
Merged

Improve lookml sql derived tables detection, add cascading derived tables to lineage #2770

Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
1928c4f
Update sql-metadata version, ignore cascading derived tables in the l…
remisalmon Jun 24, 2021
ffd534b
Add cascading derived tables in the lineage
remisalmon Jun 24, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Prev Previous commit
Add cascading derived tables in the lineage
  • Loading branch information
@remisalmon
remisalmon committed Jun 25, 2021
commit ffd534b27e7b70bec55603a1d12e421807aa0058
16 changes: 7 additions & 9 deletions metadata-ingestion/src/datahub/ingestion/source/lookml.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -199,14 +199,7 @@ class LookerView: # pragma: no cover
def _get_sql_table_names(cls, sql: str) -> List[str]:
sql_table_names: List[str] = SQLParser(sql).tables

# Remove cascading derived tables
sql_table_names = [
t
for t in sql_table_names
if not re.fullmatch('\w+\.SQL_TABLE_NAME', t)
]

# Remove quotes from tables
# Remove quotes from table names
sql_table_names = [t.replace('"', "") for t in sql_table_names]

return sql_table_names
Expand Down Expand Up @@ -379,7 +372,12 @@ def _load_model(self, path: str) -> LookerModel:
def _construct_datalineage_urn(self, sql_table_name: str, connection: str) -> str:
platform = self._get_platform_based_on_connection(connection)

if "." in platform:
# Check if table name matches cascading derived tables pattern (same platform)
if re.fullmatch(r"\w+\.SQL_TABLE_NAME", sql_table_name):
platform_name = self.source_config.platform_name
sql_table_name = sql_table_name.lower().split(".")[0]
Copy link
Contributor

@hsheth2 hsheth2 Jun 25, 2021

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is it possible that the table name is like schema.tablename.SQL_TABLE_NAME?

Copy link
Contributor Author

@remisalmon remisalmon Jun 25, 2021

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

According to the Looker doc the format is ${derived_table_or_view_name.SQL_TABLE_NAME} where derived_table_or_view_name refer to another lookml view.

See: https://docs.looker.com/data-modeling/learning-lookml/derived-tables#cascading_derived_tables and https://docs.looker.com/reference/view-params/sql_table_name-for-view

In the special case where

view: desired_view_name {
  sql_table_name: database_name.schema_name.table_name ;;
}

then derived_table_or_view_name should be equal to desired_view_name and not sql_table_name.

Copy link
Contributor

@hsheth2 hsheth2 Jun 28, 2021

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Ah I think that makes sense - thanks for clarifying

# Check if table database is in platform name (upstream platform)
elif "." in platform:
platform_name, database_name = platform.lower().split(".", maxsplit=1)
sql_table_name = f"{database_name}.{sql_table_name}".lower()
else:
Expand Down