diff --git a/wavefront/server/plugins/datasource/datasource/__init__.py b/wavefront/server/plugins/datasource/datasource/__init__.py
index 90d4d718..c6694d7c 100644
--- a/wavefront/server/plugins/datasource/datasource/__init__.py
+++ b/wavefront/server/plugins/datasource/datasource/__init__.py
@@ -13,7 +13,7 @@
 from .odata_parser import ODataQueryParser
 
 
-class DatasourcePlugin(DataSourceABC):
+class DatasourcePlugin:
     def __init__(
         self,
         datasource_type: DataSourceType,
@@ -65,7 +65,7 @@ def fetch_data(
     ) -> QueryResult:
         where_clause, params = self.odata_parser.prepare_odata_filter(filter)
         join_query, table_aliases, join_where_clause, join_params = (
-            self.odata_parser.prepare_odata_joins(join, table_name)
+            self.odata_parser.prepare_odata_joins(join or '', table_name)
         )
 
         where_clause = where_clause if where_clause else 'true'
@@ -110,13 +110,13 @@ async def execute_dynamic_query(
             rls_filter
         )
         result_by_query: Dict[str, Any] = await self.datasource.execute_dynamic_query(
-            query,
-            offset,
-            limit,
-            odata_filter,
-            odata_params,
-            odata_data_filter,
-            odata_data_params,
-            params,
+            query=query,
+            odata_filter=odata_filter,
+            odata_params=odata_params,
+            odata_data_filter=odata_data_filter,
+            odata_data_params=odata_data_params,
+            offset=offset,
+            limit=limit,
+            params=params,
         )
         return result_by_query
diff --git a/wavefront/server/plugins/datasource/datasource/bigquery/__init__.py b/wavefront/server/plugins/datasource/datasource/bigquery/__init__.py
index 380751f0..76d97a4d 100644
--- a/wavefront/server/plugins/datasource/datasource/bigquery/__init__.py
+++ b/wavefront/server/plugins/datasource/datasource/bigquery/__init__.py
@@ -20,9 +20,17 @@ def __init__(self, config: BigQueryConfig):
     async def test_connection(self) -> bool:
         return await self.client.test_connection()
 
-    def get_schema(self, table_id: str) -> dict:
-        table_info = self.client.get_table_info(self.config.dataset_id, table_id)
-        return table_info['schema'] or {}
+    def get_schema(self) -> dict:
+        tables = self.client.list_tables(self.config.dataset_id)
+        return {
+            table.table_id: (
+                self.client.get_table_info(self.config.dataset_id, table.table_id).get(
+                    'schema'
+                )
+                or {}
+            )
+            for table in tables
+        }
 
     def get_table_names(self, **kwargs) -> list[str]:
         dataset_id = kwargs.get('dataset_id', self.config.dataset_id)
@@ -32,24 +40,29 @@ def get_table_names(self, **kwargs) -> list[str]:
     def fetch_data(
         self,
         table_names: List[str],
-        projection: str = '*',
-        where_clause: str = 'true',
+        projection: Optional[str] = '*',
+        where_clause: Optional[str] = 'true',
         join_query: Optional[str] = None,
         params: Optional[Dict[str, Any]] = None,
-        offset: int = 0,
-        limit: int = 1000,
+        offset: Optional[int] = 0,
+        limit: Optional[int] = 1000,
         order_by: Optional[str] = None,
         group_by: Optional[str] = None,
     ) -> List[Dict[str, Any]]:
+        projection_value = projection or '*'
+        where_clause_value = where_clause or 'true'
+        limit_value = limit if limit is not None else 1000
+        offset_value = offset if offset is not None else 0
+
         result = self.client.execute_query_to_dict(
-            projection=projection,
+            projection=projection_value,
             table_prefix=self.table_prefix,
             table_names=table_names,
-            where_clause=where_clause,
+            where_clause=where_clause_value,
             join_query=join_query,
             params=params,
-            limit=limit,
-            offset=offset,
+            limit=limit_value,
+            offset=offset_value,
             order_by=order_by,
             group_by=group_by,
         )
@@ -73,19 +86,19 @@ async def execute_query(
 
     async def execute_dynamic_query(
         self,
-        queries: List[Dict[str, Any]],
-        offset: Optional[int] = 0,
-        limit: Optional[int] = 100,
+        query: List[Dict[str, Any]],
         odata_filter: Optional[str] = None,
         odata_params: Optional[Dict[str, Any]] = None,
         odata_data_filter: Optional[str] = None,
         odata_data_params: Optional[Dict[str, Any]] = None,
+        offset: Optional[int] = 0,
+        limit: Optional[int] = 100,
         params: Optional[Dict[str, Any]] = None,
     ) -> Dict[str, Any]:
         results = {}
         tasks = []
 
-        for query_obj in queries:
+        for query_obj in query:
             query_to_execute = query_obj.get('query', '')
             query_params = query_obj.get('parameters', [])
             query_id = query_obj.get('id')
diff --git a/wavefront/server/plugins/datasource/datasource/odata_parser.py b/wavefront/server/plugins/datasource/datasource/odata_parser.py
index fedaeb72..f222d0c4 100644
--- a/wavefront/server/plugins/datasource/datasource/odata_parser.py
+++ b/wavefront/server/plugins/datasource/datasource/odata_parser.py
@@ -79,7 +79,7 @@ def read_string(self, quote_char: str) -> str:
                 self.advance()
 
         if self.current_char == quote_char:
-            result += self.current_char
+            result += quote_char
             self.advance()
 
         return result
@@ -217,8 +217,8 @@ def get_next_token(self) -> Token:
 class ODataParserABC(ABC):
     @abstractmethod
     def prepare_odata_filter(
-        self, filter_expr: str, dynamic_var_char: str = '@'
-    ) -> Tuple[str, dict]:
+        self, filter_expr: Optional[str]
+    ) -> Tuple[Optional[str], Optional[Dict[str, Any]]]:
         pass
 
     @abstractmethod
@@ -240,7 +240,9 @@ def __init__(self, type: str, dynamic_var_char: str = '@'):
         else:
             raise ValueError(f'Invalid type: {self.type}')
 
-    def prepare_odata_filter(self, odata_filter: str) -> Dict[str, Any]:
+    def prepare_odata_filter(
+        self, odata_filter: Optional[str]
+    ) -> Tuple[Optional[str], Optional[Dict[str, Any]]]:
         return self.parser.prepare_odata_filter(odata_filter)
 
     def prepare_odata_joins(
@@ -666,7 +668,9 @@ class SQLODataParser(ODataParserABC):
     def __init__(self, dynamic_var_char: str = '@'):
         self.dynamic_var_char = dynamic_var_char
 
-    def prepare_odata_filter(self, filter_expr: str) -> Tuple[str, dict]:
+    def prepare_odata_filter(
+        self, filter_expr: Optional[str]
+    ) -> Tuple[Optional[str], Optional[Dict[str, Any]]]:
         """Parses an OData-like filter expression and converts it into a SQL-like query with parameters."""
         if not filter_expr:
             return None, None
@@ -800,6 +804,7 @@ def build_joins(
                         sql_filter, filter_params = filter_parser.prepare_odata_filter(
                             filter_expr
                         )
+                        filter_params = filter_params or {}
                         if sql_filter:
                             # Prefix the filter with table name to avoid ambiguity
                             # Replace @param with @table_param_ to match the new parameter names
diff --git a/wavefront/server/plugins/datasource/datasource/redshift/__init__.py b/wavefront/server/plugins/datasource/datasource/redshift/__init__.py
index 7de460ee..aed5a871 100644
--- a/wavefront/server/plugins/datasource/datasource/redshift/__init__.py
+++ b/wavefront/server/plugins/datasource/datasource/redshift/__init__.py
@@ -22,7 +22,11 @@ async def test_connection(self) -> bool:
         return await asyncio.to_thread(self.client.test_connection)
 
     def get_schema(self) -> dict:
-        return self.client.get_table_info()
+        table_names = self.client.list_tables()
+        return {
+            table_name: self.client.get_table_info(table_name)
+            for table_name in table_names
+        }
 
     def get_table_names(self, **kwargs) -> list[str]:
         return self.client.list_tables()
@@ -30,24 +34,29 @@ def get_table_names(self, **kwargs) -> list[str]:
     def fetch_data(
         self,
         table_names: List[str],
-        projection: str = '*',
-        where_clause: str = 'true',
+        projection: Optional[str] = '*',
+        where_clause: Optional[str] = 'true',
         join_query: Optional[str] = None,
         params: Optional[Dict[str, Any]] = None,
-        offset: int = 0,
-        limit: int = 10,
+        offset: Optional[int] = 0,
+        limit: Optional[int] = 10,
         order_by: Optional[str] = None,
         group_by: Optional[str] = None,
     ) -> List[Dict[str, Any]]:
+        projection_value = projection or '*'
+        where_clause_value = where_clause or 'true'
+        limit_value = limit if limit is not None else 10
+        offset_value = offset if offset is not None else 0
+
         return self.client.execute_query_to_dict(
-            projection=projection,
+            projection=projection_value,
             table_prefix=f'{self.db_name}.',
             table_names=table_names,
-            where_clause=where_clause,
+            where_clause=where_clause_value,
             join_query=join_query,
             params=params,
-            limit=limit,
-            offset=offset,
+            limit=limit_value,
+            offset=offset_value,
             order_by=order_by,
             group_by=group_by,
         )
diff --git a/wavefront/server/plugins/datasource/datasource/types.py b/wavefront/server/plugins/datasource/datasource/types.py
index 5aeb161e..4314ef4b 100644
--- a/wavefront/server/plugins/datasource/datasource/types.py
+++ b/wavefront/server/plugins/datasource/datasource/types.py
@@ -91,6 +91,7 @@ async def execute_dynamic_query(
         odata_data_params: Optional[Dict[str, Any]] = None,
         offset: Optional[int] = 0,
         limit: Optional[int] = 100,
+        params: Optional[Dict[str, Any]] = None,
     ) -> Dict[str, Any]:
         pass