optimization hint support for oracle and mysql

Author: RoderickJDunn

sqeleton/abcs/database_types.py

@@ -201,6 +201,10 @@ def offset_limit(self, offset: Optional[int] = None, limit: Optional[int] = None
     def explain_as_text(self, query: str) -> str:
         "Provide SQL for explaining a query, returned as table(varchar)"
 
+    @abstractmethod
+    def optimizer_hints(self, hints: str) -> str:
+        "Provide SQL for enclosing optimizer hints"
+
     @abstractmethod
     def timestamp_value(self, t: datetime) -> str:
         "Provide SQL for the given timestamp value"

sqeleton/databases/base.py

@@ -168,6 +168,9 @@ def current_timestamp(self) -> str:
     def explain_as_text(self, query: str) -> str:
         return f"EXPLAIN {query}"
 
+    def optimizer_hints(self, s: str):
+        return f"/*+ {s} */ " if s else ""
+
     def _constant_value(self, v):
         if v is None:
             return "NULL"

sqeleton/databases/bigquery.py

@@ -137,6 +137,9 @@ def type_repr(self, t) -> str:
     def set_timezone_to_utc(self) -> str:
         raise NotImplementedError()
 
+    def optimizer_hints(self, hints: str) -> str:
+        raise NotImplementedError("Optimizer hints not yet implemented in bigquery")
+
 
 class BigQuery(Database):
     CONNECT_URI_HELP = "bigquery://<project>/<dataset>"

sqeleton/databases/clickhouse.py

@@ -162,6 +162,9 @@ def set_timezone_to_utc(self) -> str:
     def current_timestamp(self) -> str:
         return "now()"
 
+    def optimizer_hints(self, hints: str) -> str:
+        raise NotImplementedError("Optimizer hints not yet implemented in clickhouse")
+
 
 class Clickhouse(ThreadedDatabase):
     dialect = Dialect()

sqeleton/databases/databricks.py

@@ -94,6 +94,9 @@ def _convert_db_precision_to_digits(self, p: int) -> int:
     def set_timezone_to_utc(self) -> str:
         return "SET TIME ZONE 'UTC'"
 
+    def optimizer_hints(self, hints: str) -> str:
+        raise NotImplementedError("Optimizer hints not yet implemented in databricks")
+
 
 class Databricks(ThreadedDatabase):
     dialect = Dialect()

sqeleton/databases/duckdb.py

@@ -136,6 +136,9 @@ def set_timezone_to_utc(self) -> str:
     def current_timestamp(self) -> str:
         return "current_timestamp"
 
+    def optimizer_hints(self, hints: str) -> str:
+        raise NotImplementedError("Optimizer hints not yet implemented in duckdb")
+
 
 class DuckDB(Database):
     dialect = Dialect()

sqeleton/databases/postgresql.py

@@ -96,6 +96,9 @@ def set_timezone_to_utc(self) -> str:
     def current_timestamp(self) -> str:
         return "current_timestamp"
 
+    def optimizer_hints(self, hints: str) -> str:
+        raise NotImplementedError("Optimizer hints not yet implemented in postgresql")
+
 
 class PostgreSQL(ThreadedDatabase):
     dialect = PostgresqlDialect()

sqeleton/databases/presto.py

@@ -141,6 +141,9 @@ def set_timezone_to_utc(self) -> str:
     def current_timestamp(self) -> str:
         return "current_timestamp"
 
+    def optimizer_hints(self, hints: str) -> str:
+        raise NotImplementedError("Optimizer hints not yet implemented in presto")
+
 
 class Presto(Database):
     dialect = Dialect()

sqeleton/databases/redshift.py

@@ -57,6 +57,8 @@ def concat(self, items: List[str]) -> str:
     def is_distinct_from(self, a: str, b: str) -> str:
         return f"({a} IS NULL != {b} IS NULL) OR ({a}!={b})"
 
+    def optimizer_hints(self, hints: str) -> str:
+        raise NotImplementedError("Optimizer hints not yet implemented in redshift")
 
 class Redshift(PostgreSQL):
     dialect = Dialect()

sqeleton/databases/snowflake.py

@@ -136,6 +136,9 @@ def table_information(self) -> Compilable:
     def set_timezone_to_utc(self) -> str:
         return "ALTER SESSION SET TIMEZONE = 'UTC'"
 
+    def optimizer_hints(self, hints: str) -> str:
+        raise NotImplementedError("Optimizer hints not yet implemented in snowflake")
+
 
 class Snowflake(Database):
     dialect = Dialect()