Do not search charset in mysql_real_connect if already set

In mysql_init() charset is set to NULL .
In mysql_read_connect() charset is not changed if already set

This allows proxysql to change it outside the library

deps/Makefile

@@ -158,6 +158,7 @@ mariadb-client-library/mariadb_client/libmariadb/libmariadbclient.a: libssl/open
 #	cd mariadb-client-library/mariadb_client && cmake . -DOPENSSL_ROOT_DIR=/usr/local/opt/openssl # this is needed on MacOSX
 	cd mariadb-client-library/mariadb_client && patch libmariadb/mariadb_stmt.c < ../mariadb_stmt.c.patch
 	cd mariadb-client-library/mariadb_client && patch libmariadb/mariadb_lib.c < ../mariadb_lib.c.patch
+	cd mariadb-client-library/mariadb_client && patch libmariadb/mariadb_lib.c < ../mariadb_lib.c.collation.patch # make sure this path is applied after mariadb_lib.c.patch
 #	cd mariadb-client-library/mariadb_client && patch libmariadb/net.c < ../net.c.patch
 	cd mariadb-client-library/mariadb_client && patch libmariadb/mariadb_async.c < ../mariadb_async.c.patch
 	cd mariadb-client-library/mariadb_client && patch libmariadb/ma_password.c < ../ma_password.c.patch

deps/mariadb-client-library/mariadb_lib.c.collation.patch

@@ -0,0 +1,33 @@
+@@ -1017,7 +1017,10 @@ mysql_init(MYSQL *mysql)
+     goto error;
+   mysql->options.report_data_truncation= 1;
+   mysql->options.connect_timeout=CONNECT_TIMEOUT;
+-  mysql->charset= mysql_find_charset_name(MARIADB_DEFAULT_CHARSET);
++  // in proxysql we set mysql->charset to NULL during mysql_init()
++  // proxysql will explicitly set it a value if needed
++  mysql->charset = NULL;
++  //mysql->charset= mysql_find_charset_name(MARIADB_DEFAULT_CHARSET);
+   mysql->methods= &MARIADB_DEFAULT_METHODS;
+   strcpy(mysql->net.sqlstate, "00000");
+   mysql->net.last_error[0]= mysql->net.last_errno= 0;
+@@ -1497,11 +1500,15 @@ MYSQL *mthd_my_real_connect(MYSQL *mysql
+     }
+   }
+
+-  /* Set character set */
+-  if (mysql->options.charset_name)
+-    mysql->charset= mysql_find_charset_name(mysql->options.charset_name);
+-  else
+-    mysql->charset=mysql_find_charset_name(MARIADB_DEFAULT_CHARSET);
++  if (!mysql->charset) { // in proxysql we do not set charset during mysql_init
++    /* Set character set */
++    if (mysql->options.charset_name)
++      mysql->charset= mysql_find_charset_name(mysql->options.charset_name);
++    else
++      mysql->charset=mysql_find_charset_name(MARIADB_DEFAULT_CHARSET);
++  } else {
++    // proxysql has explicitly set charset
++  }
+
+   if (!mysql->charset)
+   {

lib/mysql_connection.cpp

@@ -696,7 +696,8 @@ void MySQL_Connection::connect_start() {
 		mysql_variables.server_set_value(myds->sess, SQL_CHARACTER_SET_CONNECTION, ss.str().c_str());
 		mysql_variables.server_set_value(myds->sess, SQL_COLLATION_CONNECTION, ss.str().c_str());
 	}
-	mysql_options(mysql, MYSQL_SET_CHARSET_NAME, c->csname);
+	//mysql_options(mysql, MYSQL_SET_CHARSET_NAME, c->csname);
+	mysql->charset = c;
 	unsigned long client_flags = 0;
 	//if (mysql_thread___client_found_rows)
 	//	client_flags += CLIENT_FOUND_ROWS;