Georg Richter added a comment - 2014-12-20 21:40 Thanks for your bug report. Verified - the leak also exists in servers (GPL licensed) client library.

Tianhong added a comment - 2014-12-21 02:15 Hi Georg, Thanks for your reply. As you said, I've tried the same test code with the c client library from MySQL-5.6.20 and didn't find any leak. The memory usage looks quite normal.

Georg Richter added a comment - 2014-12-21 18:43 Fixed in rev. 185

Tianhong added a comment - 2014-12-21 23:47 Hi Georg, thanks for your work and support. Today I reviewed the code and thought that there are also a few bugs in function "mysql_reconnect" The problems are: 1. original options would get lost if reconnecting fails, because of the bzero() before mysql_real_connect() 2. The free_me flag in original mysql object is set to 0, which would lead to memory leak. You should store the old value and set it back after the cloning from tmp_mysql object. I wrote the patch with some comment. Please do a code review if you have time. static my_bool mysql_reconnect(MYSQL *mysql) { MYSQL tmp_mysql; //--Origial free_me flag in mysql object my_bool free_me; LIST *li_stmt= mysql->stmts; DBUG_ENTER("mysql_reconnect"); if (!mysql->reconnect || (mysql->server_status & SERVER_STATUS_IN_TRANS) || !mysql->host_info) { /* Allov reconnect next time */ mysql->server_status&= ~SERVER_STATUS_IN_TRANS; my_set_error(mysql, CR_SERVER_GONE_ERROR, SQLSTATE_UNKNOWN, 0); DBUG_RETURN(1); } mysql_init(&tmp_mysql); tmp_mysql.options=mysql->options; /* don't reread options from configuration files */ tmp_mysql.options.my_cnf_group= tmp_mysql.options.my_cnf_file= NULL; /* make sure that we reconnect with the same character set */ if (!tmp_mysql.options.charset_name || strcmp(tmp_mysql.options.charset_name, mysql->charset->csname)) { my_free(tmp_mysql.options.charset_name, MYF(MY_ALLOW_ZERO_PTR)); tmp_mysql.options.charset_name= my_strdup(mysql->charset->csname, MYF(MY_WME)); } tmp_mysql.reconnect= mysql->reconnect; //-------- BUG ---------------------------- //- We have to keep the original options -- //- So don't set the options to zero here - //bzero((char*) &mysql->options,sizeof(mysql->options)); if (!mysql_real_connect(&tmp_mysql,mysql->host,mysql->user,mysql->passwd, mysql->db, mysql->port, mysql->unix_socket, mysql->client_flag | CLIENT_REMEMBER_OPTIONS)) { my_set_error(mysql, tmp_mysql.net.last_errno, tmp_mysql.net.sqlstate, tmp_mysql.net.last_error); //--If it fails, just destroy the tmp_mysql. //--But don't delete the options in tmp_mysql //--, because the options are shared between mysql and tmp_mysql //--The options need to be reused next time. //--Set the options in tmp_mysql to NULL, in order to guard //--the original pointers of options in mysql object. bzero((char*) &tmp_mysql.options,sizeof(tmp_mysql.options)); mysql_close(&tmp_mysql); DBUG_RETURN(1); } /* reset the connection in all active statements todo: check stmt->mysql in mysql_stmt* functions ! */ for (;li_stmt;li_stmt= li_stmt->next) { MYSQL_STMT *stmt= (MYSQL_STMT *)li_stmt->data; if (stmt->state != MYSQL_STMT_INITTED) { stmt->mysql= NULL; stmt->state= MYSQL_STMT_INITTED; SET_CLIENT_STMT_ERROR(stmt, CR_SERVER_LOST, SQLSTATE_UNKNOWN, 0); } else tmp_mysql.stmts= list_add(tmp_mysql.stmts, &stmt->list); } //------------- BUG ---------------- //We also have to keep the origial free_me flag //The flag needs to be set back after cloning. free_me = mysql->free_me; mysql->free_me=0; mysql->stmts= NULL; //---- BUG ------------------------- //--The options should be set to NULL before mysql_close() //--Otherwise, the options would be deleted in mysql_close() memset(&mysql->options, 0, sizeof(mysql->options)); mysql_close(mysql); //memset(&mysql->options, 0, sizeof(mysql->options)); *mysql=tmp_mysql; //--Now, set the original free_me flag back. mysql->free_me = free_me; mysql->reconnect= 1; net_clear(&mysql->net); mysql->affected_rows= ~(my_ulonglong) 0; DBUG_RETURN(0); }