feat(ingest/snowflake): support more than 10k views in a db

metadata-ingestion/src/datahub/ingestion/source/snowflake/snowflake_query.py

@@ -5,6 +5,8 @@
 from datahub.ingestion.source.snowflake.constants import SnowflakeObjectDomain
 from datahub.ingestion.source.snowflake.snowflake_config import DEFAULT_TABLES_DENY_LIST
 
+SHOW_VIEWS_MAX_PAGE_SIZE = 10000
+
 
 def create_deny_regex_sql_filter(
     deny_pattern: List[str], filter_cols: List[str]
@@ -202,48 +204,28 @@ def get_tags_on_columns_with_propagation(
         FROM table("{db_name}".information_schema.tag_references_all_columns('{quoted_table_identifier}', '{SnowflakeObjectDomain.TABLE}'));
         """
 
-    # View definition is retrived in information_schema query only if role is owner of view. Hence this query is not used.
-    # https://community.snowflake.com/s/article/Is-it-possible-to-see-the-view-definition-in-information-schema-views-from-a-non-owner-role
     @staticmethod
-    def views_for_database(db_name: Optional[str]) -> str:
-        db_clause = f'"{db_name}".' if db_name is not None else ""
-        return f"""
-        SELECT table_catalog AS "TABLE_CATALOG",
-        table_schema AS "TABLE_SCHEMA",
-        table_name AS "TABLE_NAME",
-        created AS "CREATED",
-        last_altered AS "LAST_ALTERED",
-        comment AS "COMMENT",
-        view_definition AS "VIEW_DEFINITION"
-        FROM {db_clause}information_schema.views t
-        WHERE table_schema != 'INFORMATION_SCHEMA'
-        order by table_schema, table_name"""
-
-    # View definition is retrived in information_schema query only if role is owner of view. Hence this query is not used.
-    # https://community.snowflake.com/s/article/Is-it-possible-to-see-the-view-definition-in-information-schema-views-from-a-non-owner-role
-    @staticmethod
-    def views_for_schema(schema_name: str, db_name: Optional[str]) -> str:
-        db_clause = f'"{db_name}".' if db_name is not None else ""
-        return f"""
-        SELECT table_catalog AS "TABLE_CATALOG",
-        table_schema AS "TABLE_SCHEMA",
-        table_name AS "TABLE_NAME",
-        created AS "CREATED",
-        last_altered AS "LAST_ALTERED",
-        comment AS "COMMENT",
-        view_definition AS "VIEW_DEFINITION"
-        FROM {db_clause}information_schema.views t
-        where table_schema='{schema_name}'
-        order by table_schema, table_name"""
+    def show_views_for_database(
+        db_name: str,
+        limit: int = SHOW_VIEWS_MAX_PAGE_SIZE,
+        view_pagination_marker: Optional[str] = None,
+    ) -> str:
+        # While there is an information_schema.views view, that only shows the view definition if the role
+        # is an owner of the view. That doesn't work for us.
+        # https://community.snowflake.com/s/article/Is-it-possible-to-see-the-view-definition-in-information-schema-views-from-a-non-owner-role
 
-    @staticmethod
-    def show_views_for_database(db_name: str) -> str:
-        return f"""show views in database "{db_name}";"""
+        # SHOW VIEWS can return a maximum of 10000 rows.
+        # https://docs.snowflake.com/en/sql-reference/sql/show-views#usage-notes
+        assert limit <= SHOW_VIEWS_MAX_PAGE_SIZE
 
-    @staticmethod
-    def show_views_for_schema(schema_name: str, db_name: Optional[str]) -> str:
-        db_clause = f'"{db_name}".' if db_name is not None else ""
-        return f"""show views in schema {db_clause}"{schema_name}";"""
+        # To work around this, we paginate through the results using the FROM clause.
+        from_clause = (
+            f"""FROM '{view_pagination_marker}'""" if view_pagination_marker else ""
+        )
+        return f"""\
+SHOW VIEWS IN DATABASE "{db_name}"
+LIMIT {limit} {from_clause};
+"""
 
     @staticmethod
     def columns_for_schema(schema_name: str, db_name: Optional[str]) -> str:

metadata-ingestion/src/datahub/ingestion/source/snowflake/snowflake_report.py

@@ -117,7 +117,6 @@ class SnowflakeV2Report(
     # "Information schema query returned too much data. Please repeat query with more selective predicates.""
     # This will result in overall increase in time complexity
     num_get_tables_for_schema_queries: int = 0
-    num_get_views_for_schema_queries: int = 0
     num_get_columns_for_table_queries: int = 0
 
     # these will be non-zero if the user choses to enable the extract_tags = "with_lineage" option, which requires

metadata-ingestion/src/datahub/ingestion/source/snowflake/snowflake_schema.py

@@ -9,7 +9,10 @@
 
 from datahub.ingestion.api.report import SupportsAsObj
 from datahub.ingestion.source.snowflake.constants import SnowflakeObjectDomain
-from datahub.ingestion.source.snowflake.snowflake_query import SnowflakeQuery
+from datahub.ingestion.source.snowflake.snowflake_query import (
+    SHOW_VIEWS_MAX_PAGE_SIZE,
+    SnowflakeQuery,
+)
 from datahub.ingestion.source.snowflake.snowflake_utils import SnowflakeQueryMixin
 from datahub.ingestion.source.sql.sql_generic import BaseColumn, BaseTable, BaseView
 from datahub.utilities.serialized_lru_cache import serialized_lru_cache
@@ -324,53 +327,54 @@ def get_tables_for_schema(
         return tables
 
     @serialized_lru_cache(maxsize=1)
-    def get_views_for_database(
-        self, db_name: str
-    ) -> Optional[Dict[str, List[SnowflakeView]]]:
+    def get_views_for_database(self, db_name: str) -> Dict[str, List[SnowflakeView]]:
+        page_limit = SHOW_VIEWS_MAX_PAGE_SIZE
+
         views: Dict[str, List[SnowflakeView]] = {}
-        try:
-            cur = self.query(SnowflakeQuery.show_views_for_database(db_name))
-        except Exception as e:
-            logger.debug(
-                f"Failed to get all views for database - {db_name}", exc_info=e
-            )
-            # Error - Information schema query returned too much data. Please repeat query with more selective predicates.
-            return None
 
-        for table in cur:
-            if table["schema_name"] not in views:
-                views[table["schema_name"]] = []
-            views[table["schema_name"]].append(
-                SnowflakeView(
-                    name=table["name"],
-                    created=table["created_on"],
-                    # last_altered=table["last_altered"],
-                    comment=table["comment"],
-                    view_definition=table["text"],
-                    last_altered=table["created_on"],
-                    materialized=table.get("is_materialized", "false").lower()
-                    == "true",
+        first_iteration = True
+        view_pagination_marker: Optional[str] = None
+        while first_iteration or view_pagination_marker is not None:
+            cur = self.query(
+                SnowflakeQuery.show_views_for_database(
+                    db_name,
+                    limit=page_limit,
+                    view_pagination_marker=view_pagination_marker,
                 )
             )
-        return views
 
-    def get_views_for_schema(
-        self, schema_name: str, db_name: str
-    ) -> List[SnowflakeView]:
-        views: List[SnowflakeView] = []
+            first_iteration = False
+            view_pagination_marker = None
+
+            result_set_size = 0
+            for view in cur:
+                result_set_size += 1
+
+                view_name = view["name"]
+                schema_name = view["schema_name"]
+                if schema_name not in views:
+                    views[schema_name] = []
+                views[schema_name].append(
+                    SnowflakeView(
+                        name=view_name,
+                        created=view["created_on"],
+                        # last_altered=table["last_altered"],
+                        comment=view["comment"],
+                        view_definition=view["text"],
+                        last_altered=view["created_on"],
+                        materialized=(
+                            view.get("is_materialized", "false").lower() == "true"
+                        ),
+                    )
+                )
 
-        cur = self.query(SnowflakeQuery.show_views_for_schema(schema_name, db_name))
-        for table in cur:
-            views.append(
-                SnowflakeView(
-                    name=table["name"],
-                    created=table["created_on"],
-                    # last_altered=table["last_altered"],
-                    comment=table["comment"],
-                    view_definition=table["text"],
-                    last_altered=table["created_on"],
+            if result_set_size >= page_limit:
+                # If we hit the limit, we need to send another request to get the next page.
+                logger.info(
+                    f"Fetching next page of views for {db_name} - after {view_name}"
                 )
-            )
+                view_pagination_marker = view_name
+
         return views
 
     @serialized_lru_cache(maxsize=SCHEMA_PARALLELISM)

metadata-ingestion/src/datahub/ingestion/source/snowflake/snowflake_schema_gen.py

@@ -1011,12 +1011,6 @@ def get_views_for_schema(
     ) -> List[SnowflakeView]:
         views = self.data_dictionary.get_views_for_database(db_name)
 
-        # get all views for database failed,
-        # falling back to get views for schema
-        if views is None:
-            self.report.num_get_views_for_schema_queries += 1
-            return self.data_dictionary.get_views_for_schema(schema_name, db_name)
-
         # Some schema may not have any table
         return views.get(schema_name, [])
 

metadata-ingestion/tests/integration/snowflake/common.py

@@ -224,8 +224,6 @@ def default_query_results(  # noqa: C901
         ]
     elif query == SnowflakeQuery.tables_for_database("TEST_DB"):
         raise Exception("Information schema query returned too much data")
-    elif query == SnowflakeQuery.show_views_for_database("TEST_DB"):
-        raise Exception("Information schema query returned too much data")
     elif query == SnowflakeQuery.tables_for_schema("TEST_SCHEMA", "TEST_DB"):
         return [
             {
@@ -241,7 +239,8 @@ def default_query_results(  # noqa: C901
             }
             for tbl_idx in range(1, num_tables + 1)
         ]
-    elif query == SnowflakeQuery.show_views_for_schema("TEST_SCHEMA", "TEST_DB"):
+    elif query == SnowflakeQuery.show_views_for_database("TEST_DB"):
+        # TODO: Add tests for view pagination.
         return [
             {
                 "schema_name": "TEST_SCHEMA",

metadata-ingestion/tests/integration/snowflake/test_snowflake_failures.py

@@ -144,7 +144,7 @@ def test_snowflake_no_tables_causes_pipeline_failure(
         )
         sf_cursor.execute.side_effect = query_permission_response_override(
             no_tables_fn,
-            [SnowflakeQuery.show_views_for_schema("TEST_SCHEMA", "TEST_DB")],
+            [SnowflakeQuery.show_views_for_database("TEST_DB")],
             [],
         )