public static ShowResultSet execute(ShowStmt statement, ConnectContext context) {
        return GlobalStateMgr.getCurrentState().getShowExecutor().showExecutorVisitor.visit(statement, context);
    }
@Test
    public void testShowCreateExternalCatalogNotExists() {
        new MockUp<CatalogMgr>() {
            @Mock
            public Catalog getCatalogByName(String name) {
                return null;
            }
        };

        ShowCreateExternalCatalogStmt stmt = new ShowCreateExternalCatalogStmt("catalog_not_exist");

        ExceptionChecker.expectThrowsWithMsg(SemanticException.class, "Unknown catalog 'catalog_not_exist'",
                () -> ShowExecutor.execute(stmt, ctx));
    }