feat(cubesql): Add support for current_catalog function for postgresql protocol (#9839)

Author: mgaudin-open

rust/cubesql/cubesql/src/compile/engine/udf/common.rs

@@ -4346,13 +4346,6 @@ pub fn register_fun_stubs(mut ctx: SessionContext) -> SessionContext {
     register_fun_stub!(udf, "cosh", tsig = [Float64], rettyp = Float64);
     register_fun_stub!(udf, "cot", tsig = [Float64], rettyp = Float64);
     register_fun_stub!(udf, "cotd", tsig = [Float64], rettyp = Float64);
-    register_fun_stub!(
-        udf,
-        "current_catalog",
-        argc = 0,
-        rettyp = Utf8,
-        vol = Stable
-    );
     register_fun_stub!(udf, "current_query", argc = 0, rettyp = Utf8, vol = Stable);
     register_fun_stub!(udf, "current_role", argc = 0, rettyp = Utf8, vol = Stable);
     register_fun_stub!(

rust/cubesql/cubesql/src/compile/query_engine.rs

@@ -436,6 +436,7 @@ impl QueryEngine for SqlQueryEngine {
                 "PostgreSQL 14.2 on x86_64-cubesql".to_string(),
             ));
             ctx.register_udf(create_db_udf("current_database".to_string(), state.clone()));
+            ctx.register_udf(create_db_udf("current_catalog".to_string(), state.clone()));
             ctx.register_udf(create_db_udf("current_schema".to_string(), state.clone()));
             ctx.register_udf(create_current_user_udf(
                 state.clone(),

rust/cubesql/cubesql/src/compile/test/snapshots/cubesql__compile__test__test_introspection__datagrip_introspection.snap

@@ -1,9 +1,9 @@
 ---
 source: cubesql/src/compile/test/test_introspection.rs
-expression: "execute_query(\"select current_database(), current_schema(), current_user;\".to_string(),\nDatabaseProtocol::PostgreSQL).await?"
+expression: "execute_query(\"select current_database(), current_catalog, current_schema(), current_user;\".to_string(),\nDatabaseProtocol::PostgreSQL).await?"
 ---
-+------------------+----------------+--------------+
-| current_database | current_schema | current_user |
-+------------------+----------------+--------------+
-| cubedb           | public         | ovr          |
-+------------------+----------------+--------------+
++------------------+-----------------+----------------+--------------+
+| current_database | current_catalog | current_schema | current_user |
++------------------+-----------------+----------------+--------------+
+| cubedb           | cubedb          | public         | ovr          |
++------------------+-----------------+----------------+--------------+

rust/cubesql/cubesql/src/compile/test/test_introspection.rs

@@ -842,7 +842,8 @@ async fn datagrip_introspection() -> Result<(), CubeError> {
     insta::assert_snapshot!(
         "datagrip_introspection",
         execute_query(
-            "select current_database(), current_schema(), current_user;".to_string(),
+            "select current_database(), current_catalog, current_schema(), current_user;"
+                .to_string(),
             DatabaseProtocol::PostgreSQL
         )
         .await?