Add a workaround to drop the bad table instead of truncating

src/sql_generator.cpp

@@ -281,6 +281,15 @@ void alter_table_recreate(duckdb::Connection &con, const table_def &table,
             "Could not drop table <" + absolute_temp_table_name + ">");
 }
 
+// this is only used for a temporary workaround --
+// https://github.com/MotherDuck-Open-Source/motherduck-fivetran-connector/issues/51
+void drop_table(duckdb::Connection &con, const table_def &table) {
+  auto absolute_table_name = table.to_escaped_string();
+
+  run_query(con, "Dropping table", "DROP TABLE " + absolute_table_name,
+            "Could not directly drop table <" + absolute_table_name + ">");
+}
+
 void alter_table_in_place(
     duckdb::Connection &con, const std::string &absolute_table_name,
     const std::set<std::string> &added_columns,
@@ -494,8 +503,19 @@ void truncate_table(duckdb::Connection &con, const table_def &table,
                     const std::string &deleted_column) {
   const std::string absolute_table_name = table.to_escaped_string();
   std::ostringstream sql;
-
   mdlog::info("truncate_table request: deleted column = " + deleted_column);
+
+  // this is only used for a temporary workaround --
+  // https://github.com/MotherDuck-Open-Source/motherduck-fivetran-connector/issues/51
+  auto duckdb_columns = describe_table(con, table);
+  if (duckdb_columns.size() == 1 &&
+      duckdb_columns[0].name == "_fivetran_deleted") {
+    mdlog::info("truncate_table: dropping bad table with only "
+                "_fivetran_deleted column");
+    drop_table(con, table);
+    return;
+  }
+
   if (deleted_column.empty()) {
     // hard delete
     sql << "DELETE FROM " << absolute_table_name;

test/integration/test_server.cpp

@@ -1522,8 +1522,7 @@ TEST_CASE("AlterTable with constraints", "[integration]") {
   }
 }
 
-TEST_CASE("Invalid truncate with nonexisting delete column",
-          "[integration][current]") {
+TEST_CASE("Invalid truncate with nonexisting delete column", "[integration]") {
   DestinationSdkImpl service;
 
   const std::string table_name =
@@ -1572,3 +1571,65 @@ TEST_CASE("Invalid truncate with nonexisting delete column",
             "Referenced column \"_fivetran_synced\" not found in FROM clause"));
   }
 }
+
+TEST_CASE("Temp fix to drop table with only _fivetran_deleted column",
+          "[integration]") {
+  DestinationSdkImpl service;
+
+  const std::string table_name =
+      "table_with_only_deleted_column_" + std::to_string(Catch::rngSeed());
+  auto token = std::getenv("motherduck_token");
+  REQUIRE(token);
+
+  {
+    // Create Table that is missing the _fivetran_deleted column
+    ::fivetran_sdk::CreateTableRequest request;
+    (*request.mutable_configuration())["motherduck_token"] = token;
+    (*request.mutable_configuration())["motherduck_database"] =
+        TEST_DATABASE_NAME;
+    request.mutable_table()->set_name(table_name);
+    auto col1 = request.mutable_table()->add_columns();
+    col1->set_name("_fivetran_deleted");
+    col1->set_type(::fivetran_sdk::DataType::BOOLEAN);
+
+    ::fivetran_sdk::CreateTableResponse response;
+    auto status = service.CreateTable(nullptr, &request, &response);
+    REQUIRE_NO_FAIL(status);
+  }
+
+  auto con = get_test_connection(token);
+  const std::string table_exists_query =
+      "SELECT table_name FROM information_schema.tables WHERE table_catalog='" +
+      TEST_DATABASE_NAME + "' AND table_schema='main' AND table_name='" +
+      table_name + "'";
+  {
+    // make sure table exists
+    auto res = con->Query(table_exists_query);
+    REQUIRE(res->RowCount() == 1);
+  }
+
+  {
+    // Attempt to truncate the bad table
+    ::fivetran_sdk::TruncateRequest request;
+    (*request.mutable_configuration())["motherduck_token"] = token;
+    (*request.mutable_configuration())["motherduck_database"] =
+        TEST_DATABASE_NAME;
+    request.set_table_name(table_name);
+    request.set_synced_column(
+        "_fivetran_synced"); // does not exist but the code won't get there
+    request.mutable_soft()->set_deleted_column("_fivetran_deleted");
+
+    const auto cutoff_datetime = 1707436800; // 2024-02-09 0:0:0 GMT, trust me
+    request.mutable_utc_delete_before()->set_seconds(cutoff_datetime);
+    request.mutable_utc_delete_before()->set_nanos(0);
+    ::fivetran_sdk::TruncateResponse response;
+    auto status = service.Truncate(nullptr, &request, &response);
+    REQUIRE_NO_FAIL(status);
+  }
+
+  {
+    // make sure table no longer exists
+    auto res = con->Query(table_exists_query);
+    REQUIRE(res->RowCount() == 0);
+  }
+}