diff --git a/CMakeLists.txt b/CMakeLists.txt
index ec0c3ba..0ce8327 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,6 +4,8 @@ set(CMAKE_CXX_STANDARD          17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS        OFF)
 
+# set(CMAKE_CXX_FLAGS "-O3 -Wall -Wextra")
+
 set(CMAKE_OSX_DEPLOYMENT_TARGET "10.14")
 
 
@@ -20,4 +22,3 @@ add_executable(${PROJECT_NAME} ${SOURCE})
 
 target_link_libraries(${PROJECT_NAME} stdc++ m)
 
-target_compile_options(usql PRIVATE -g)
diff --git a/Readme.md b/Readme.md
index 89ebd20..08a5e9d 100644
--- a/Readme.md
+++ b/Readme.md
@@ -3,6 +3,7 @@
 - is null | is not null
 - coalesce, date functions now, add_date; string functions rtrim, ltrim, rpad, lpad; math function round
 - add pipe | concatenation
+- add support for 1_000_000 numbers
 
 - support for order by, offset, limit (allow column name in order by, validate)
 - support for uniqueue indexes (primary key)
@@ -13,5 +14,4 @@
 - use string_to_double and string_to_long (from Table) everywhere
 - add const wherever should be
 - use static methods where posible
-- PERF in Row::Row(const Row &other), could be more efficient (memory and cpu)
 - use references where pointer cannot be nullptr
diff --git a/exception.cpp b/exception.cpp
index cee6b18..028cdea 100644
--- a/exception.cpp
+++ b/exception.cpp
@@ -2,11 +2,6 @@
 
 namespace usql {
 
-Exception::Exception(const std::string &msg) : std::runtime_error(msg) {
-	cause = msg;
-}
+Exception::Exception(const std::string msg) : std::runtime_error(msg) {}
 
-
-const char *Exception::what() const noexcept { return cause.c_str(); }
-
-}
+}	// namespace
diff --git a/exception.h b/exception.h
index aab3ec3..9670174 100644
--- a/exception.h
+++ b/exception.h
@@ -7,13 +7,8 @@
 namespace usql {
 
 class Exception : public std::runtime_error {
-private:
-    std::string cause;
-
 public:
-    Exception(const std::string &msg);
-
-    const char *what() const noexcept;
+    Exception(const std::string msg);
 };
 
-}
\ No newline at end of file
+}	// namespace
\ No newline at end of file
diff --git a/lexer.cpp b/lexer.cpp
index 66e4bc8..4de4020 100644
--- a/lexer.cpp
+++ b/lexer.cpp
@@ -13,8 +13,8 @@ namespace usql {
 
     Lexer::Lexer() {
     	k_words_regex =
-    		    "[-+]?[0-9]+\\.[0-9]+|[-+]?[0-9][0-9_]+[0-9]|[0-9]+|[A-Za-z]+[A-Za-z0-9_#]*|[\\(\\)\\[\\]\\{\\}]|[-\\+\\*/"
-			",;:\?]|!=|<>|==|>=|<=|~=|>|<|=|;|~|\\||or|and|\n|\r|\r\n|'([^']|'')*'|\".*?\"|%.*?\n";
+    		    "[-+]?[0-9]+\\.[0-9]+|[-+]?[0-9]+|[A-Za-z]+[A-Za-z0-9_#]*|[\\(\\)\\[\\]\\{\\}]|[-\\+\\*/"
+			",;:\?]|!=|<>|==|>=|<=|~=|>|<|=|;|~|\\||\n|\r|\r\n|'([^']|'')*'|\".*?\"|%.*?\n";
     	k_int_regex = "[-+]?[0-9]+";
 	k_int_underscored_regex = "[-+]?[0-9][0-9_]+[0-9]";
 	k_double_regex = "[-+]?[0-9]+\\.[0-9]+";
diff --git a/ml_date.cpp b/ml_date.cpp
index 07ac1fb..4d95f8c 100644
--- a/ml_date.cpp
+++ b/ml_date.cpp
@@ -19,8 +19,8 @@ std::string date_to_string(const long datetime, const std::string format) {
 		std::string result = {mbstr};
 		return result;
 	}
-	// TODO exception here
-	return "invalid argument";
+
+	throw std::runtime_error("date_to_string, invalid date string or format");
 }
 
 time_t time_to_epoch ( const struct tm *ltm, int utcdiff ) {
@@ -71,8 +71,7 @@ long string_to_date(const std::string &datestr, const std::string &format) {
 		return time_to_epoch(timeinfo, -1 * timeinfo->tm_gmtoff);
 	}
 
-	// throw Exception("invalid date string or format");
-	return -1;
+	throw std::runtime_error("string_to_date, invalid date string or format");
 }
 
 
diff --git a/row.cpp b/row.cpp
index 89e0cd8..7557d0c 100644
--- a/row.cpp
+++ b/row.cpp
@@ -172,13 +172,10 @@ int Row::print_get_column_size(const ColDefNode &col_def) {
 	switch (col_def.type) {
 		case ColumnType::varchar_type:
 			return col_def.length;
-			break;
 		case ColumnType::date_type:
 			return 19;
-			break;
 		case ColumnType::float_type:
 			return 16;
-			break;
 		default:
 			return 10;
 	}