/* * This file is distributed as part of the MariaDB Corporation MaxScale. It is free * software: you can redistribute it and/or modify it under the terms of the * GNU General Public License as published by the Free Software Foundation, * version 2. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more * details. * * You should have received a copy of the GNU General Public License along with * this program; if not, write to the Free Software Foundation, Inc., 51 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. * * Copyright MariaDB Corporation Ab 2013-2014 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include MODULE_INFO info = { MODULE_API_ROUTER, MODULE_BETA_RELEASE, ROUTER_VERSION, "A database sharding router for simple sharding" }; #if defined(SS_DEBUG) # include #endif /** Defined in log_manager.cc */ extern int lm_enabled_logfiles_bitmask; extern size_t log_ses_count[]; extern __thread log_info_t tls_log_info; /** * @file readwritesplit.c The entry points for the read/write query splitting * router module. * * This file contains the entry points that comprise the API to the read write * query splitting router. * @verbatim * Revision History * * Date Who Description * 01/07/2013 Vilho Raatikka Initial implementation * 15/07/2013 Massimiliano Pinto Added clientReply * from master only in case of session change * 17/07/2013 Massimiliano Pinto clientReply is now used by mysql_backend * for all reply situations * 18/07/2013 Massimiliano Pinto routeQuery now handles COM_QUIT * as QUERY_TYPE_SESSION_WRITE * 17/07/2014 Massimiliano Pinto Server connection counter is updated in closeSession * * @endverbatim */ static char *version_str = "V1.0.2"; static ROUTER* createInstance(SERVICE *service, char **options); static void* newSession(ROUTER *instance, SESSION *session); static void closeSession(ROUTER *instance, void *session); static void freeSession(ROUTER *instance, void *session); static int routeQuery(ROUTER *instance, void *session, GWBUF *queue); static void diagnostic(ROUTER *instance, DCB *dcb); static void clientReply( ROUTER* instance, void* router_session, GWBUF* queue, DCB* backend_dcb); static void handleError( ROUTER* instance, void* router_session, GWBUF* errmsgbuf, DCB* backend_dcb, error_action_t action, bool* succp); static void print_error_packet(ROUTER_CLIENT_SES* rses, GWBUF* buf, DCB* dcb); static int router_get_servercount(ROUTER_INSTANCE* router); static backend_ref_t* get_bref_from_dcb(ROUTER_CLIENT_SES* rses, DCB* dcb); static route_target_t get_shard_route_target ( skygw_query_type_t qtype, bool trx_active, target_t use_sql_variables_in, HINT* hint); #if 0 static backend_ref_t* check_candidate_bref( backend_ref_t* candidate_bref, backend_ref_t* new_bref, select_criteria_t sc); #endif static uint8_t getCapabilities (ROUTER* inst, void* router_session); #if defined(NOT_USED) static bool router_option_configured( ROUTER_INSTANCE* router, const char* optionstr, void* data); #endif #if defined(PREP_STMT_CACHING) static prep_stmt_t* prep_stmt_init(prep_stmt_type_t type, void* id); static void prep_stmt_done(prep_stmt_t* pstmt); #endif /*< PREP_STMT_CACHING */ int bref_cmp_global_conn( const void* bref1, const void* bref2); int bref_cmp_router_conn( const void* bref1, const void* bref2); int bref_cmp_behind_master( const void* bref1, const void* bref2); int bref_cmp_current_load( const void* bref1, const void* bref2); static bool connect_backend_servers( backend_ref_t* backend_ref, int router_nservers, SESSION* session, ROUTER_INSTANCE* router); static bool get_shard_dcb( DCB** dcb, ROUTER_CLIENT_SES* rses, char* name); #if 0 static void rwsplit_process_router_options( ROUTER_INSTANCE* router, char** options); #endif static ROUTER_OBJECT MyObject = { createInstance, newSession, closeSession, freeSession, routeQuery, diagnostic, clientReply, handleError, getCapabilities }; static bool rses_begin_locked_router_action( ROUTER_CLIENT_SES* rses); static void rses_end_locked_router_action( ROUTER_CLIENT_SES* rses); static void mysql_sescmd_done( mysql_sescmd_t* sescmd); static mysql_sescmd_t* mysql_sescmd_init ( rses_property_t* rses_prop, GWBUF* sescmd_buf, unsigned char packet_type, ROUTER_CLIENT_SES* rses); static rses_property_t* mysql_sescmd_get_property( mysql_sescmd_t* scmd); static rses_property_t* rses_property_init( rses_property_type_t prop_type); static void rses_property_add( ROUTER_CLIENT_SES* rses, rses_property_t* prop); static void rses_property_done( rses_property_t* prop); static mysql_sescmd_t* rses_property_get_sescmd( rses_property_t* prop); static bool execute_sescmd_history(backend_ref_t* bref); static bool execute_sescmd_in_backend( backend_ref_t* backend_ref); static void sescmd_cursor_reset(sescmd_cursor_t* scur); static bool sescmd_cursor_history_empty(sescmd_cursor_t* scur); static void sescmd_cursor_set_active( sescmd_cursor_t* sescmd_cursor, bool value); static bool sescmd_cursor_is_active( sescmd_cursor_t* sescmd_cursor); static GWBUF* sescmd_cursor_clone_querybuf( sescmd_cursor_t* scur); static mysql_sescmd_t* sescmd_cursor_get_command( sescmd_cursor_t* scur); static bool sescmd_cursor_next( sescmd_cursor_t* scur); static GWBUF* sescmd_cursor_process_replies(GWBUF* replybuf, backend_ref_t* bref); static void tracelog_routed_query( ROUTER_CLIENT_SES* rses, char* funcname, backend_ref_t* bref, GWBUF* buf); static void dbshard_process_router_options( ROUTER_INSTANCE* router, char** options); static bool route_session_write( ROUTER_CLIENT_SES* router_client_ses, GWBUF* querybuf, ROUTER_INSTANCE* inst, unsigned char packet_type, skygw_query_type_t qtype); static void refreshInstance( ROUTER_INSTANCE* router, CONFIG_PARAMETER* param); static void bref_clear_state(backend_ref_t* bref, bref_state_t state); static void bref_set_state(backend_ref_t* bref, bref_state_t state); static sescmd_cursor_t* backend_ref_get_sescmd_cursor (backend_ref_t* bref); static int router_handle_state_switch(DCB* dcb, DCB_REASON reason, void* data); static bool handle_error_new_connection( ROUTER_INSTANCE* inst, ROUTER_CLIENT_SES* rses, DCB* backend_dcb, GWBUF* errmsg); static void handle_error_reply_client( SESSION* ses, ROUTER_CLIENT_SES* rses, DCB* backend_dcb, GWBUF* errmsg); static backend_ref_t* get_root_master_bref(ROUTER_CLIENT_SES* rses); static BACKEND* get_root_master( backend_ref_t* servers, int router_nservers); static SPINLOCK instlock; static ROUTER_INSTANCE* instances; static int hashkeyfun(void* key); static int hashcmpfun (void *, void *); static int hashkeyfun( void* key) { if(key == NULL){ return 0; } unsigned int hash = 0,c = 0; char* ptr = (char*)key; while((c = *ptr++)){ hash = c + (hash << 6) + (hash << 16) - hash; } return *(int *)key; } static int hashcmpfun( void* v1, void* v2) { char* i1 = (char*) v1; char* i2 = (char*) v2; return strcmp(i1,i2); } static void* hstrdup(void* fval) { char* str = (char*)fval; return strdup(str); } static void* hfree(void* fval) { free (fval); return NULL; } /** * Updates the hashtable with the database names and where to find them, adding * new and removing obsolete pairs. * @param backends Backends to query for database names * @param hashtable Hashtable to use * @return True if all database and server names were successfully retrieved * otherwise false */ bool update_dbnames_hash(BACKEND** backends, HASHTABLE* hashtable) { const unsigned int connect_timeout = 15; const unsigned int read_timeout = 10; bool rval = true; SERVER* server; int i, rc, numfields; for(i = 0;backends[i];i++) { MYSQL* handle = mysql_init(NULL); MYSQL_RES* result = NULL; MYSQL_ROW row; char *user,*pwd = NULL; if(handle == NULL) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error: Failed to initialize " "MySQL handle."))); return false; } rc = 0; rc |= mysql_options(handle, MYSQL_OPT_CONNECT_TIMEOUT, (void *)&connect_timeout); rc |= mysql_options(handle, MYSQL_OPT_READ_TIMEOUT, (void *)&read_timeout); if(rc != 0) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error: Failed to set MySQL connection options."))); mysql_close(handle); rval = false; continue; } server = backends[i]->backend_server; ss_dassert(server != NULL); if(server->monuser == NULL || server->monpw == NULL) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error: No username or password " "defined for server '%s'.", server->unique_name))); rval = false; goto cleanup; } /** Plain-text password used for authentication for now */ user = server->monuser; pwd = server->monpw; if (mysql_real_connect(handle, server->name, user, pwd, NULL, server->port, NULL, 0) == NULL) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error: Failed to connect to backend " "server '%s': %d %s", server->name, mysql_errno(handle), mysql_error(handle)))); rval = false; goto cleanup; } /** * The server was successfully connected to, proceed to query for database names */ if((result = mysql_list_dbs(handle,NULL)) == NULL) { LOGIF(LE, (skygw_log_write_flush(LOGFILE_ERROR, "Error: Failed to retrieve databases from backend " "server '%s': %d %s", server->name, mysql_errno(handle), mysql_error(handle)))); goto cleanup; } numfields = mysql_num_fields(result); if(numfields < 1) { LOGIF(LT, (skygw_log_write_flush( LOGFILE_TRACE, "Backend '%s' has no databases.", server->name))); goto cleanup; } /** * Walk through the list of databases in this backend * and insert them into the hashtable. If the value is already in the hashtable * but the backend isn't in the list of backends it is replaced with the first found backend. */ while((row = mysql_fetch_row(result))) { unsigned long *lengths; char *dbnm = NULL,*servnm = NULL; lengths = mysql_fetch_lengths(result); /** * Default databases to ignore */ if(strncmp(row[0],"information_schema",lengths[0]) == 0 || strncmp(row[0],"performance_schema",lengths[0]) == 0 || strncmp(row[0],"mysql",lengths[0]) == 0 || strncmp(row[0],"mysqlslap",lengths[0]) == 0 || strncmp(row[0],"test",lengths[0]) == 0){ continue; } dbnm = (char*)calloc(lengths[0] + 1,sizeof(char)); memcpy(dbnm,row[0],lengths[0]); servnm = strdup(server->unique_name); if(hashtable_add(hashtable,dbnm,servnm) == 0) { char* srvname; #ifdef SHARD_UPDATES { char* old_backend = (char*)hashtable_fetch(hashtable,dbnm); int j; bool is_alive = false; for(j = 0;backends[j];j++) { /** * See if the old backend is still * alive. If not then update * the hashtable with the current backend's name. */ if(strcmp(server->unique_name,old_backend) == 0 && SERVER_IS_RUNNING(server)) { is_alive = true; } } if(!is_alive) { hashtable_delete(hashtable,dbnm); if(hashtable_add(hashtable,dbnm,servnm)) { LOGIF(LT, (skygw_log_write_flush( LOGFILE_TRACE, "Updated the backend of database '%s' to '%s'.", dbnm, servnm))); } else { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error: Failed to insert values into hashtable."))); } } goto cleanup; } #endif /*< SHARD_UPDATES */ /*Check if the failure was due to a duplicate value*/ if((srvname = hashtable_fetch(hashtable,dbnm)) == NULL) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error: Failed to insert values into hashtable."))); } else { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Conflicting " "databases found. " "Both \"%s\" and \"%s\" " "have a database \"%s\".", server->unique_name, srvname, dbnm))); } rval = false; free(dbnm); free(servnm); } /*< hashtable_add failed */ } /*< while */ cleanup: if(result) { mysql_free_result(result); } result = NULL; mysql_close(handle); } /*< for */ return rval; } /** * Allocates a new hashtable and inserts database names and where to find them * into it. * @param backends Backends to query for database names * @return Pointer to the newly allocated hashtable or NULL if an error occurred */ void* dbnames_hash_init(BACKEND** backends) { HASHTABLE* htbl = hashtable_alloc(512,hashkeyfun,hashcmpfun); if(htbl == NULL) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error: Hashtable allocation failed."))); return NULL; } /**Update the new hashtable with the key-value pairs*/ if(!update_dbnames_hash(backends,htbl)) { /* LOGIF(LE, (skygw_log_write_flush(LOGFILE_ERROR,"Errors encountered while querying databases."))); hashtable_free(htbl); return NULL; */ hashtable_free(htbl); htbl = NULL; } return htbl; } bool add_shard_info(GWBUF* buffer, char* target) { HINT* hint = hint_create_route(NULL,HINT_ROUTE_TO_NAMED_SERVER,target); return (bool)gwbuf_add_hint(buffer,hint); } char* get_shard_target_name(ROUTER_INSTANCE* router, ROUTER_CLIENT_SES* client, GWBUF* buffer){ HASHTABLE* ht = router->dbnames_hash; int sz = 0,i,j; char** dbnms = NULL; char* rval = NULL; bool has_dbs = false; /**If the query targets any database other than the current one*/ if(!query_is_parsed(buffer)){ parse_query(buffer); } dbnms = skygw_get_database_names(buffer,&sz); if(sz > 0){ has_dbs = true; for(i = 0; i < sz; i++){ if((rval = (char*)hashtable_fetch(ht,dbnms[i]))){ for(j = i;j < sz;j++) free(dbnms[j]); break; } free(dbnms[i]); } free(dbnms); } /** * If the query contains no explicitly stated databases proceed to * check if the session has an active database and if it is sharded. */ if(rval == NULL && !has_dbs && client->rses_mysql_session->db[0] != '\0'){ rval = (char*)hashtable_fetch(ht,client->rses_mysql_session->db); } return rval; } /** * Implementation of the mandatory version entry point * * @return version string of the module */ char * version() { return version_str; } /** * The module initialisation routine, called when the module * is first loaded. */ void ModuleInit() { LOGIF(LM, (skygw_log_write_flush( LOGFILE_MESSAGE, "Initializing statemend-based read/write split router module."))); spinlock_init(&instlock); instances = NULL; } /** * The module entry point routine. It is this routine that * must populate the structure that is referred to as the * "module object", this is a structure with the set of * external entry points for this module. * * @return The module object */ ROUTER_OBJECT* GetModuleObject() { return &MyObject; } static void refreshInstance( ROUTER_INSTANCE* router, CONFIG_PARAMETER* singleparam) { CONFIG_PARAMETER* param; bool refresh_single; config_param_type_t paramtype; if (singleparam != NULL) { param = singleparam; refresh_single = true; } else { param = router->service->svc_config_param; refresh_single = false; } paramtype = config_get_paramtype(param); while (param != NULL) { /** Catch unused parameter types */ ss_dassert(paramtype == COUNT_TYPE || paramtype == PERCENT_TYPE || paramtype == SQLVAR_TARGET_TYPE); if (paramtype == COUNT_TYPE) { } else if (paramtype == PERCENT_TYPE) { } else if (paramtype == SQLVAR_TARGET_TYPE) { if (strncmp(param->name, "use_sql_variables_in", MAX_PARAM_LEN) == 0) { target_t valtarget; bool succp; succp = config_get_valtarget(&valtarget, param, NULL, paramtype); if (succp) { router->dbshard_config.rw_use_sql_variables_in = valtarget; } } } if (refresh_single) { break; } param = param->next; } #if defined(NOT_USED) /*< can't read monitor config parameters */ if ((*router->servers)->backend_server->rlag == -2) { rlag_enabled = false; } else { rlag_enabled = true; } /** * If replication lag detection is not enabled the measure can't be * used in slave selection. */ if (!rlag_enabled) { if (rlag_limited) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Warning : Configuration Failed, max_slave_replication_lag " "is set to %d,\n\t\t but detect_replication_lag " "is not enabled. Replication lag will not be checked.", router->dbshard_config.rw_max_slave_replication_lag))); } if (router->dbshard_config.rw_slave_select_criteria == LEAST_BEHIND_MASTER) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Warning : Configuration Failed, router option " "\n\t\t slave_selection_criteria=LEAST_BEHIND_MASTER " "is specified, but detect_replication_lag " "is not enabled.\n\t\t " "slave_selection_criteria=%s will be used instead.", STRCRITERIA(DEFAULT_CRITERIA)))); router->dbshard_config.rw_slave_select_criteria = DEFAULT_CRITERIA; } } #endif /*< NOT_USED */ } /** * Create an instance of dbshard statement router within the MaxScale. * * * @param service The service this router is being create for * @param options The options for this query router * * @return NULL in failure, pointer to router in success. */ static ROUTER * createInstance(SERVICE *service, char **options) { ROUTER_INSTANCE* router; SERVER* server; int nservers; int i; if ((router = calloc(1, sizeof(ROUTER_INSTANCE))) == NULL) { return NULL; } router->service = service; spinlock_init(&router->lock); /** Calculate number of servers */ server = service->databases; nservers = 0; while (server != NULL) { nservers++; server=server->nextdb; } router->servers = (BACKEND **)calloc(nservers + 1, sizeof(BACKEND *)); if (router->servers == NULL) { free(router); return NULL; } /** * Create an array of the backend servers in the router structure to * maintain a count of the number of connections to each * backend server. */ server = service->databases; nservers= 0; while (server != NULL) { if ((router->servers[nservers] = malloc(sizeof(BACKEND))) == NULL) { goto clean_up; } router->servers[nservers]->backend_server = server; router->servers[nservers]->backend_conn_count = 0; router->servers[nservers]->weight = 1; router->servers[nservers]->be_valid = false; if(server->monuser == NULL && service->credentials.name != NULL) { router->servers[nservers]->backend_server->monuser = strdup(service->credentials.name); } if(server->monpw == NULL && service->credentials.authdata != NULL) { router->servers[nservers]->backend_server->monpw = strdup(service->credentials.authdata); } #if defined(SS_DEBUG) router->servers[nservers]->be_chk_top = CHK_NUM_BACKEND; router->servers[nservers]->be_chk_tail = CHK_NUM_BACKEND; #endif nservers += 1; server = server->nextdb; } router->servers[nservers] = NULL; /** * Process the options */ router->bitmask = 0; router->bitvalue = 0; /** * Read config version number from service to inform what configuration * is used if any. */ router->dbshard_version = service->svc_config_version; /** refreshInstance(router, NULL); */ /** * Get hashtable which includes dbname,backend pairs */ router->dbnames_hash = (HASHTABLE*)dbnames_hash_init(router->servers); if (router->dbnames_hash == NULL) { goto clean_up; } /** * We have completed the creation of the router data, so now * insert this router into the linked list of routers * that have been created with this module. */ spinlock_acquire(&instlock); router->next = instances; instances = router; spinlock_release(&instlock); goto retblock; clean_up: /** clean up */ for (i = 0; i < nservers; i++) { free(router->servers[i]); } free(router->servers); free(router); router = NULL; /** Fallthrough */ retblock: return (ROUTER *)router; } /** * Associate a new session with this instance of the router. * * The session is used to store all the data required for a particular * client connection. * * @param instance The router instance data * @param session The session itself * @return Session specific data for this session */ static void* newSession( ROUTER* router_inst, SESSION* session) { backend_ref_t* backend_ref; /*< array of backend references (DCB,BACKEND,cursor) */ ROUTER_CLIENT_SES* client_rses = NULL; ROUTER_INSTANCE* router = (ROUTER_INSTANCE *)router_inst; bool succp; int router_nservers = 0; /*< # of servers in total */ int i; #if 0 /** * It could be possibe to accept new session if some of the servers are * not reachable */ const int min_nservers = 1; /*< hard-coded for now */ #endif client_rses = (ROUTER_CLIENT_SES *)calloc(1, sizeof(ROUTER_CLIENT_SES)); if (client_rses == NULL) { ss_dassert(false); goto return_rses; } #if defined(SS_DEBUG) client_rses->rses_chk_top = CHK_NUM_ROUTER_SES; client_rses->rses_chk_tail = CHK_NUM_ROUTER_SES; #endif client_rses->router = router; client_rses->rses_mysql_session = (MYSQL_session*)session->data; /** * If service config has been changed, reload config from service to * router instance first. */ spinlock_acquire(&router->lock); /** * ??? tarvitaanko - ei vielä */ #if 0 if (router->service->svc_config_version > router->dbshard_version) { /** re-read all parameters to rwsplit config structure */ refreshInstance(router, NULL); /*< scan through all parameters */ /** increment rwsplit router's config version number */ router->dbshard_version = router->service->svc_config_version; /** Read options */ dbshard_process_router_options(router, router->service->routerOptions); } /** Copy config struct from router instance */ client_rses->rses_config = router->dbshard_config; #endif spinlock_release(&router->lock); /** * Set defaults to session variables. * ??? tarvitaanko */ client_rses->rses_autocommit_enabled = true; client_rses->rses_transaction_active = false; /** * Instead of calling this, ensure that there is at least one * responding server. */ router_nservers = router_get_servercount(router); #if 0 if (!have_enough_servers(&client_rses, min_nservers, router_nservers, router)) { goto return_rses; } #endif /** * Create backend reference objects for this session. */ backend_ref = (backend_ref_t *)calloc(1, router_nservers*sizeof(backend_ref_t)); if (backend_ref == NULL) { /** log this */ free(client_rses); free(backend_ref); client_rses = NULL; goto return_rses; } /** * Initialize backend references with BACKEND ptr. * Initialize session command cursors for each backend reference. */ for (i=0; i< router_nservers; i++) { #if defined(SS_DEBUG) backend_ref[i].bref_chk_top = CHK_NUM_BACKEND_REF; backend_ref[i].bref_chk_tail = CHK_NUM_BACKEND_REF; backend_ref[i].bref_sescmd_cur.scmd_cur_chk_top = CHK_NUM_SESCMD_CUR; backend_ref[i].bref_sescmd_cur.scmd_cur_chk_tail = CHK_NUM_SESCMD_CUR; #endif backend_ref[i].bref_state = 0; backend_ref[i].bref_backend = router->servers[i]; /** store pointers to sescmd list to both cursors */ backend_ref[i].bref_sescmd_cur.scmd_cur_rses = client_rses; backend_ref[i].bref_sescmd_cur.scmd_cur_active = false; backend_ref[i].bref_sescmd_cur.scmd_cur_ptr_property = &client_rses->rses_properties[RSES_PROP_TYPE_SESCMD]; backend_ref[i].bref_sescmd_cur.scmd_cur_cmd = NULL; } spinlock_init(&client_rses->rses_lock); client_rses->rses_backend_ref = backend_ref; /** * Find a backend servers to connect to. * This command requires that rsession's lock is held. */ if (!(succp = rses_begin_locked_router_action(client_rses))) { free(client_rses->rses_backend_ref); free(client_rses); client_rses = NULL; goto return_rses; } /** * Connect to all backend servers */ succp = connect_backend_servers(backend_ref, router_nservers, session, router); rses_end_locked_router_action(client_rses); /** * Master and at least slaves must be found */ if (!succp) { free(client_rses->rses_backend_ref); free(client_rses); client_rses = NULL; goto return_rses; } /** Copy backend pointers to router session. */ client_rses->rses_capabilities = RCAP_TYPE_STMT_INPUT; client_rses->rses_backend_ref = backend_ref; client_rses->rses_nbackends = router_nservers; /*< # of backend servers */ router->stats.n_sessions += 1; /** * Version is bigger than zero once initialized. */ atomic_add(&client_rses->rses_versno, 2); ss_dassert(client_rses->rses_versno == 2); /** * Add this session to end of the list of active sessions in router. */ spinlock_acquire(&router->lock); client_rses->next = router->connections; router->connections = client_rses; spinlock_release(&router->lock); return_rses: #if defined(SS_DEBUG) if (client_rses != NULL) { CHK_CLIENT_RSES(client_rses); } #endif return (void *)client_rses; } /** * Close a session with the router, this is the mechanism * by which a router may cleanup data structure etc. * * @param instance The router instance data * @param session The session being closed */ static void closeSession( ROUTER* instance, void* router_session) { ROUTER_CLIENT_SES* router_cli_ses; backend_ref_t* backend_ref; LOGIF(LD, (skygw_log_write(LOGFILE_DEBUG, "%lu [RWSplit:closeSession]", pthread_self()))); /** * router session can be NULL if newSession failed and it is discarding * its connections and DCB's. */ if (router_session == NULL) { return; } router_cli_ses = (ROUTER_CLIENT_SES *)router_session; CHK_CLIENT_RSES(router_cli_ses); backend_ref = router_cli_ses->rses_backend_ref; /** * Lock router client session for secure read and update. */ if (!router_cli_ses->rses_closed && rses_begin_locked_router_action(router_cli_ses)) { int i; /** * This sets router closed. Nobody is allowed to use router * whithout checking this first. */ router_cli_ses->rses_closed = true; for (i=0; irses_nbackends; i++) { backend_ref_t* bref = &backend_ref[i]; DCB* dcb = bref->bref_dcb; /** Close those which had been connected */ if (BREF_IS_IN_USE(bref)) { CHK_DCB(dcb); #if defined(SS_DEBUG) /** * session must be moved to SESSION_STATE_STOPPING state before * router session is closed. */ if (dcb->session != NULL) { ss_dassert(dcb->session->state == SESSION_STATE_STOPPING); } #endif /** Clean operation counter in bref and in SERVER */ while (BREF_IS_WAITING_RESULT(bref)) { bref_clear_state(bref, BREF_WAITING_RESULT); } bref_clear_state(bref, BREF_IN_USE); bref_set_state(bref, BREF_CLOSED); /** * closes protocol and dcb */ dcb_close(dcb); /** decrease server current connection counters */ atomic_add(&bref->bref_backend->backend_server->stats.n_current, -1); atomic_add(&bref->bref_backend->backend_conn_count, -1); } } /** Unlock */ rses_end_locked_router_action(router_cli_ses); } } static void freeSession( ROUTER* router_instance, void* router_client_session) { ROUTER_CLIENT_SES* router_cli_ses; ROUTER_INSTANCE* router; int i; backend_ref_t* backend_ref; router_cli_ses = (ROUTER_CLIENT_SES *)router_client_session; router = (ROUTER_INSTANCE *)router_instance; backend_ref = router_cli_ses->rses_backend_ref; for (i=0; irses_nbackends; i++) { if (!BREF_IS_IN_USE((&backend_ref[i]))) { continue; } } spinlock_acquire(&router->lock); if (router->connections == router_cli_ses) { router->connections = router_cli_ses->next; } else { ROUTER_CLIENT_SES* ptr = router->connections; while (ptr && ptr->next != router_cli_ses) { ptr = ptr->next; } if (ptr) { ptr->next = router_cli_ses->next; } } spinlock_release(&router->lock); /** * For each property type, walk through the list, finalize properties * and free the allocated memory. */ for (i=RSES_PROP_TYPE_FIRST; irses_properties[i]; rses_property_t* q = p; while (p != NULL) { q = p->rses_prop_next; rses_property_done(p); p = q; } } /* * We are no longer in the linked list, free * all the memory and other resources associated * to the client session. */ free(router_cli_ses->rses_backend_ref); free(router_cli_ses); return; } /** * Provide the router with a pointer to a suitable backend dcb. * * Detect failures in server statuses and reselect backends if necessary. * If name is specified, server name becomes primary selection criteria. * Similarly, if max replication lag is specified, skip backends which lag too * much. * * @param p_dcb Address of the pointer to the resulting DCB * @param rses Pointer to router client session * @param btype Backend type * @param name Name of the backend which is primarily searched. May be NULL. * * @return True if proper DCB was found, false otherwise. */ static bool get_shard_dcb( DCB** p_dcb, ROUTER_CLIENT_SES* rses, char* name) { backend_ref_t* backend_ref; int i; bool succp = false; CHK_CLIENT_RSES(rses); ss_dassert(p_dcb != NULL && *(p_dcb) == NULL); if (p_dcb == NULL || name == NULL) { goto return_succp; } backend_ref = rses->rses_backend_ref; for (i=0; irses_nbackends; i++) { BACKEND* b = backend_ref[i].bref_backend; /** * To become chosen: * backend must be in use, name must match, and * the backend state must be RUNNING */ if (BREF_IS_IN_USE((&backend_ref[i])) && (strncasecmp( name, b->backend_server->unique_name, PATH_MAX) == 0) && SERVER_IS_RUNNING(b->backend_server)) { *p_dcb = backend_ref[i].bref_dcb; succp = true; ss_dassert(backend_ref[i].bref_dcb->state != DCB_STATE_ZOMBIE); goto return_succp; } } return_succp: return succp; } /** * ??? Tarvitaanko tätä */ #if 0 /** * Find out which of the two backend servers has smaller value for select * criteria property. * * @param cand previously selected candidate * @param new challenger * @param sc select criteria * * @return pointer to backend reference of that backend server which has smaller * value in selection criteria. If either reference pointer is NULL then the * other reference pointer value is returned. */ static backend_ref_t* check_candidate_bref( backend_ref_t* cand, backend_ref_t* new, select_criteria_t sc) { int (*p)(const void *, const void *); /** get compare function */ p = criteria_cmpfun[sc]; if (new == NULL) { return cand; } else if (cand == NULL || (p((void *)cand,(void *)new) > 0)) { return new; } else { return cand; } } #endif /** * Examine the query type, transaction state and routing hints. Find out the * target for query routing. * * @param qtype Type of query * @param trx_active Is transacation active or not * @param hint Pointer to list of hints attached to the query buffer * * @return bitfield including the routing target, or the target server name * if the query would otherwise be routed to slave. */ static route_target_t get_shard_route_target ( skygw_query_type_t qtype, bool trx_active, /*< !!! turha ? */ target_t use_sql_variables_in, /*< 'master' == single tässä tapauksessa */ HINT* hint) /*< !!! turha ? */ { route_target_t target = TARGET_UNDEFINED; /** * These queries are not affected by hints */ if (QUERY_IS_TYPE(qtype, QUERY_TYPE_SESSION_WRITE) || QUERY_IS_TYPE(qtype, QUERY_TYPE_PREPARE_STMT) || QUERY_IS_TYPE(qtype, QUERY_TYPE_PREPARE_NAMED_STMT) || /** Configured to allow writing variables to all nodes */ (use_sql_variables_in == TYPE_ALL && QUERY_IS_TYPE(qtype, QUERY_TYPE_GSYSVAR_WRITE)) || /** enable or disable autocommit are always routed to all */ QUERY_IS_TYPE(qtype, QUERY_TYPE_ENABLE_AUTOCOMMIT) || QUERY_IS_TYPE(qtype, QUERY_TYPE_DISABLE_AUTOCOMMIT)) { /** hints don't affect on routing */ target = TARGET_ALL; } else { target = TARGET_NAMED_SERVER; } #if defined(SS_DEBUG) LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Selected target \"%s\"", STRTARGET(target)))); #endif return target; } /** * Check if the query is a DROP TABLE... query and * if it targets a temporary table, remove it from the hashtable. * @param instance Router instance * @param router_session Router client session * @param querybuf GWBUF containing the query * @param type The type of the query resolved so far */ void check_drop_tmp_table( ROUTER* instance, void* router_session, GWBUF* querybuf, skygw_query_type_t type) { int tsize = 0, klen = 0,i; char** tbl = NULL; char *hkey,*dbname; ROUTER_CLIENT_SES* router_cli_ses = (ROUTER_CLIENT_SES *)router_session; rses_property_t* rses_prop_tmp; rses_prop_tmp = router_cli_ses->rses_properties[RSES_PROP_TYPE_TMPTABLES]; dbname = router_cli_ses->rses_mysql_session->db; if (is_drop_table_query(querybuf)) { tbl = skygw_get_table_names(querybuf,&tsize,false); if(tbl != NULL){ for(i = 0; irses_prop_data.temp_tables) { if (hashtable_delete(rses_prop_tmp->rses_prop_data.temp_tables, (void *)hkey)) { LOGIF(LT, (skygw_log_write(LOGFILE_TRACE, "Temporary table dropped: %s",hkey))); } } free(tbl[i]); free(hkey); } free(tbl); } } } /** * Check if the query targets a temporary table. * @param instance Router instance * @param router_session Router client session * @param querybuf GWBUF containing the query * @param type The type of the query resolved so far * @return The type of the query */ skygw_query_type_t is_read_tmp_table( ROUTER* instance, void* router_session, GWBUF* querybuf, skygw_query_type_t type) { bool target_tmp_table = false; int tsize = 0, klen = 0,i; char** tbl = NULL; char *hkey,*dbname; ROUTER_CLIENT_SES* router_cli_ses = (ROUTER_CLIENT_SES *)router_session; skygw_query_type_t qtype = type; rses_property_t* rses_prop_tmp; rses_prop_tmp = router_cli_ses->rses_properties[RSES_PROP_TYPE_TMPTABLES]; dbname = router_cli_ses->rses_mysql_session->db; if (QUERY_IS_TYPE(qtype, QUERY_TYPE_READ) || QUERY_IS_TYPE(qtype, QUERY_TYPE_LOCAL_READ) || QUERY_IS_TYPE(qtype, QUERY_TYPE_USERVAR_READ) || QUERY_IS_TYPE(qtype, QUERY_TYPE_SYSVAR_READ) || QUERY_IS_TYPE(qtype, QUERY_TYPE_GSYSVAR_READ)) { tbl = skygw_get_table_names(querybuf,&tsize,false); if (tbl != NULL && tsize > 0) { /** Query targets at least one table */ for(i = 0; irses_prop_data.temp_tables) { if( (target_tmp_table = (bool)hashtable_fetch(rses_prop_tmp->rses_prop_data.temp_tables,(void *)hkey))) { /**Query target is a temporary table*/ qtype = QUERY_TYPE_READ_TMP_TABLE; LOGIF(LT, (skygw_log_write(LOGFILE_TRACE, "Query targets a temporary table: %s",hkey))); } } free(hkey); } } } if(tbl != NULL){ for(i = 0; irses_properties[RSES_PROP_TYPE_TMPTABLES]; dbname = router_cli_ses->rses_mysql_session->db; if (QUERY_IS_TYPE(type, QUERY_TYPE_CREATE_TMP_TABLE)) { bool is_temp = true; char* tblname = NULL; tblname = skygw_get_created_table_name(querybuf); if (tblname && strlen(tblname) > 0) { klen = strlen(dbname) + strlen(tblname) + 2; hkey = calloc(klen,sizeof(char)); strcpy(hkey,dbname); strcat(hkey,"."); strcat(hkey,tblname); } else { hkey = NULL; } if(rses_prop_tmp == NULL) { if((rses_prop_tmp = (rses_property_t*)calloc(1,sizeof(rses_property_t)))) { #if defined(SS_DEBUG) rses_prop_tmp->rses_prop_chk_top = CHK_NUM_ROUTER_PROPERTY; rses_prop_tmp->rses_prop_chk_tail = CHK_NUM_ROUTER_PROPERTY; #endif rses_prop_tmp->rses_prop_rsession = router_cli_ses; rses_prop_tmp->rses_prop_refcount = 1; rses_prop_tmp->rses_prop_next = NULL; rses_prop_tmp->rses_prop_type = RSES_PROP_TYPE_TMPTABLES; router_cli_ses->rses_properties[RSES_PROP_TYPE_TMPTABLES] = rses_prop_tmp; } else { LOGIF(LE, (skygw_log_write_flush(LOGFILE_ERROR,"Error : Call to malloc() failed."))); } } if(rses_prop_tmp){ if (rses_prop_tmp->rses_prop_data.temp_tables == NULL) { h = hashtable_alloc(7, hashkeyfun, hashcmpfun); hashtable_memory_fns(h,hstrdup,NULL,hfree,NULL); if (h != NULL) { rses_prop_tmp->rses_prop_data.temp_tables = h; }else{ LOGIF(LE, (skygw_log_write_flush(LOGFILE_ERROR,"Error : Failed to allocate a new hashtable."))); } } if (hkey && rses_prop_tmp->rses_prop_data.temp_tables && hashtable_add(rses_prop_tmp->rses_prop_data.temp_tables, (void *)hkey, (void *)is_temp) == 0) /*< Conflict in hash table */ { LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Temporary table conflict in hashtable: %s", hkey))); } #if defined(SS_DEBUG) { bool retkey = hashtable_fetch( rses_prop_tmp->rses_prop_data.temp_tables, hkey); if (retkey) { LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Temporary table added: %s", hkey))); } } #endif } free(hkey); free(tblname); } } /** * The main routing entry, this is called with every packet that is * received and has to be forwarded to the backend database. * * The routeQuery will make the routing decision based on the contents * of the instance, session and the query itself in the queue. The * data in the queue may not represent a complete query, it represents * the data that has been received. The query router itself is responsible * for buffering the partial query, a later call to the query router will * contain the remainder, or part thereof of the query. * * @param instance The query router instance * @param router_session The session associated with the client * @param querybuf MaxScale buffer queue with received packet * * @return if succeed 1, otherwise 0 * If routeQuery fails, it means that router session has failed. * In any tolerated failure, handleError is called and if necessary, * an error message is sent to the client. * * For now, routeQuery don't tolerate errors, so any error will close * the session. vraa 14.6.14 */ static int routeQuery( ROUTER* instance, void* router_session, GWBUF* querybuf) { skygw_query_type_t qtype = QUERY_TYPE_UNKNOWN; mysql_server_cmd_t packet_type; uint8_t* packet; int ret = 0; DCB* target_dcb = NULL; ROUTER_INSTANCE* inst = (ROUTER_INSTANCE *)instance; ROUTER_CLIENT_SES* router_cli_ses = (ROUTER_CLIENT_SES *)router_session; bool rses_is_closed = false; route_target_t route_target; bool succp = false; char* tname = NULL; CHK_CLIENT_RSES(router_cli_ses); /** Dirty read for quick check if router is closed. */ if (router_cli_ses->rses_closed) { rses_is_closed = true; } ss_dassert(!GWBUF_IS_TYPE_UNDEFINED(querybuf)); packet = GWBUF_DATA(querybuf); packet_type = packet[4]; if (rses_is_closed) { /** * MYSQL_COM_QUIT may have sent by client and as a part of backend * closing procedure. */ if (packet_type != MYSQL_COM_QUIT) { char* query_str = modutil_get_query(querybuf); LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error: Can't route %s:%s:\"%s\" to " "backend server. Router is closed.", STRPACKETTYPE(packet_type), STRQTYPE(qtype), (query_str == NULL ? "(empty)" : query_str)))); free(query_str); } ret = 0; goto retblock; } /** If buffer is not contiguous, make it such */ if (querybuf->next != NULL) { querybuf = gwbuf_make_contiguous(querybuf); } switch(packet_type) { case MYSQL_COM_QUIT: /*< 1 QUIT will close all sessions */ case MYSQL_COM_INIT_DB: /*< 2 DDL must go to the master */ if(GWBUF_LENGTH(querybuf) <= MYSQL_DATABASE_MAXLEN - 5) { strncpy(router_cli_ses->rses_mysql_session->db, (char*)(packet + 5), (int)(GWBUF_LENGTH(querybuf) - 5)); /** * Update the session's active database only if it's in the hashtable. * If it isn't found, send a custom error packet to the client. */ if(hashtable_fetch(inst->dbnames_hash, (char*)router_cli_ses->rses_mysql_session->db) == NULL) { router_cli_ses->rses_mysql_session->db[0] = '\0'; /**TODO: Add error packet*/ } } case MYSQL_COM_REFRESH: /*< 7 - I guess this is session but not sure */ case MYSQL_COM_DEBUG: /*< 0d all servers dump debug info to stdout */ case MYSQL_COM_PING: /*< 0e all servers are pinged */ case MYSQL_COM_CHANGE_USER: /*< 11 all servers change it accordingly */ case MYSQL_COM_STMT_CLOSE: /*< free prepared statement */ case MYSQL_COM_STMT_SEND_LONG_DATA: /*< send data to column */ case MYSQL_COM_STMT_RESET: /*< resets the data of a prepared statement */ qtype = QUERY_TYPE_SESSION_WRITE; break; case MYSQL_COM_CREATE_DB: /**< 5 DDL must go to the master */ case MYSQL_COM_DROP_DB: /**< 6 DDL must go to the master */ qtype = QUERY_TYPE_WRITE; break; case MYSQL_COM_QUERY: qtype = query_classifier_get_type(querybuf); break; case MYSQL_COM_STMT_PREPARE: qtype = query_classifier_get_type(querybuf); qtype |= QUERY_TYPE_PREPARE_STMT; break; case MYSQL_COM_STMT_EXECUTE: /** Parsing is not needed for this type of packet */ qtype = QUERY_TYPE_EXEC_STMT; break; case MYSQL_COM_SHUTDOWN: /**< 8 where should shutdown be routed ? */ case MYSQL_COM_STATISTICS: /**< 9 ? */ case MYSQL_COM_PROCESS_INFO: /**< 0a ? */ case MYSQL_COM_CONNECT: /**< 0b ? */ case MYSQL_COM_PROCESS_KILL: /**< 0c ? */ case MYSQL_COM_TIME: /**< 0f should this be run in gateway ? */ case MYSQL_COM_DELAYED_INSERT: /**< 10 ? */ case MYSQL_COM_DAEMON: /**< 1d ? */ default: break; } /**< switch by packet type */ /** * !!! Temporary tablen tutkiminen voi olla turhaa. Poista tarvittaessa. */ /** * Check if the query has anything to do with temporary tables. */ qtype = is_read_tmp_table(instance,router_session,querybuf,qtype); check_create_tmp_table(instance,router_session,querybuf,qtype); check_drop_tmp_table(instance,router_session,querybuf,qtype); /** * !!! Transaktion tutkiminen voi olla turhaa paitsi jos haluataan * lokittaa. Poista tarvittaessa. */ /** * If autocommit is disabled or transaction is explicitly started * transaction becomes active and master gets all statements until * transaction is committed and autocommit is enabled again. */ if (router_cli_ses->rses_autocommit_enabled && QUERY_IS_TYPE(qtype, QUERY_TYPE_DISABLE_AUTOCOMMIT)) { router_cli_ses->rses_autocommit_enabled = false; if (!router_cli_ses->rses_transaction_active) { router_cli_ses->rses_transaction_active = true; } } else if (!router_cli_ses->rses_transaction_active && QUERY_IS_TYPE(qtype, QUERY_TYPE_BEGIN_TRX)) { router_cli_ses->rses_transaction_active = true; } /** * Explicit COMMIT and ROLLBACK, implicit COMMIT. */ if (router_cli_ses->rses_autocommit_enabled && router_cli_ses->rses_transaction_active && (QUERY_IS_TYPE(qtype,QUERY_TYPE_COMMIT) || QUERY_IS_TYPE(qtype,QUERY_TYPE_ROLLBACK))) { router_cli_ses->rses_transaction_active = false; } else if (!router_cli_ses->rses_autocommit_enabled && QUERY_IS_TYPE(qtype, QUERY_TYPE_ENABLE_AUTOCOMMIT)) { router_cli_ses->rses_autocommit_enabled = true; router_cli_ses->rses_transaction_active = false; } if (LOG_IS_ENABLED(LOGFILE_TRACE)) { uint8_t* packet = GWBUF_DATA(querybuf); unsigned char ptype = packet[4]; size_t len = MIN(GWBUF_LENGTH(querybuf), MYSQL_GET_PACKET_LEN((unsigned char *)querybuf->start)-1); char* data = (char*)&packet[5]; char* contentstr = strndup(data, len); char* qtypestr = skygw_get_qtype_str(qtype); skygw_log_write( LOGFILE_TRACE, "> Autocommit: %s, trx is %s, cmd: %s, type: %s, " "stmt: %s%s %s", (router_cli_ses->rses_autocommit_enabled ? "[enabled]" : "[disabled]"), (router_cli_ses->rses_transaction_active ? "[open]" : "[not open]"), STRPACKETTYPE(ptype), (qtypestr==NULL ? "N/A" : qtypestr), contentstr, (querybuf->hint == NULL ? "" : ", Hint:"), (querybuf->hint == NULL ? "" : STRHINTTYPE(querybuf->hint->type))); free(contentstr); free(qtypestr); } /** * Find out whether the query should be routed to single server or to * all of them. */ /** * Find out where to route the query. Result may not be clear; it is * possible to have a hint for routing to a named server which can * be either slave or master. * If query would otherwise be routed to slave then the hint determines * actual target server if it exists. * * route_target is a bitfield and may include : * TARGET_ALL * - route to all connected backend servers * TARGET_SLAVE[|TARGET_NAMED_SERVER|TARGET_RLAG_MAX] * - route primarily according to hints, then to slave and if those * failed, eventually to master * TARGET_MASTER[|TARGET_NAMED_SERVER|TARGET_RLAG_MAX] * - route primarily according to the hints and if they failed, * eventually to master */ /** * Added for simple sharding, using hints for testing. */ if((tname = get_shard_target_name(inst,router_cli_ses,querybuf)) != NULL) { route_target = TARGET_NAMED_SERVER; } else { route_target = get_shard_route_target(qtype, router_cli_ses->rses_transaction_active, router_cli_ses->rses_config.rw_use_sql_variables_in, querybuf->hint); } if (TARGET_IS_ALL(route_target)) { /** * It is not sure if the session command in question requires * response. Statement is examined in route_session_write. * Router locking is done inside the function. */ succp = route_session_write(router_cli_ses, gwbuf_clone(querybuf), inst, packet_type, qtype); if (succp) { atomic_add(&inst->stats.n_all, 1); ret = 1; } goto retblock; } /** Lock router session */ if (!rses_begin_locked_router_action(router_cli_ses)) { LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Route query aborted! Routing session is closed <"))); ret = 0; goto retblock; } /** * Query is routed to one of the backends */ if (TARGET_IS_NAMED_SERVER(route_target)) { /** * Search backend server by name or replication lag. * If it fails, then try to find valid slave or master. */ succp = get_shard_dcb(&target_dcb, router_cli_ses, tname); if (!succp) { LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Was supposed to route to named server " "%s but couldn't find the server in a " "suitable state.", tname))); } } if (succp) /*< Have DCB of the target backend */ { backend_ref_t* bref; sescmd_cursor_t* scur; bref = get_bref_from_dcb(router_cli_ses, target_dcb); scur = &bref->bref_sescmd_cur; LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Route query to \t%s:%d <", bref->bref_backend->backend_server->name, bref->bref_backend->backend_server->port))); /** * Store current stmt if execution of previous session command * haven't completed yet. Note that according to MySQL protocol * there can only be one such non-sescmd stmt at the time. */ if (sescmd_cursor_is_active(scur)) { ss_dassert(bref->bref_pending_cmd == NULL); bref->bref_pending_cmd = gwbuf_clone(querybuf); rses_end_locked_router_action(router_cli_ses); ret = 1; goto retblock; } if ((ret = target_dcb->func.write(target_dcb, gwbuf_clone(querybuf))) == 1) { backend_ref_t* bref; atomic_add(&inst->stats.n_queries, 1); /** * Add one query response waiter to backend reference */ bref = get_bref_from_dcb(router_cli_ses, target_dcb); bref_set_state(bref, BREF_QUERY_ACTIVE); bref_set_state(bref, BREF_WAITING_RESULT); } else { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Routing query failed."))); } } rses_end_locked_router_action(router_cli_ses); retblock: #if defined(SS_DEBUG2) { char* canonical_query_str; canonical_query_str = skygw_get_canonical(querybuf); if (canonical_query_str != NULL) { LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Canonical version: %s", canonical_query_str))); free(canonical_query_str); } } #endif gwbuf_free(querybuf); return ret; } /** * @node Acquires lock to router client session if it is not closed. * * Parameters: * @param rses - in, use * * * @return true if router session was not closed. If return value is true * it means that router is locked, and must be unlocked later. False, if * router was closed before lock was acquired. * * * @details (write detailed description here) * */ static bool rses_begin_locked_router_action( ROUTER_CLIENT_SES* rses) { bool succp = false; CHK_CLIENT_RSES(rses); if (rses->rses_closed) { goto return_succp; } spinlock_acquire(&rses->rses_lock); if (rses->rses_closed) { spinlock_release(&rses->rses_lock); goto return_succp; } succp = true; return_succp: return succp; } /** to be inline'd */ /** * @node Releases router client session lock. * * Parameters: * @param rses - * * * @return void * * * @details (write detailed description here) * */ static void rses_end_locked_router_action( ROUTER_CLIENT_SES* rses) { CHK_CLIENT_RSES(rses); spinlock_release(&rses->rses_lock); } /** * Diagnostics routine * * Print query router statistics to the DCB passed in * * @param instance The router instance * @param dcb The DCB for diagnostic output */ static void diagnostic(ROUTER *instance, DCB *dcb) { ROUTER_CLIENT_SES *router_cli_ses; ROUTER_INSTANCE *router = (ROUTER_INSTANCE *)instance; int i = 0; BACKEND *backend; char *weightby; spinlock_acquire(&router->lock); router_cli_ses = router->connections; while (router_cli_ses) { i++; router_cli_ses = router_cli_ses->next; } spinlock_release(&router->lock); dcb_printf(dcb, "\tNumber of router sessions: %d\n", router->stats.n_sessions); dcb_printf(dcb, "\tCurrent no. of router sessions: %d\n", i); dcb_printf(dcb, "\tNumber of queries forwarded: %d\n", router->stats.n_queries); dcb_printf(dcb, "\tNumber of queries forwarded to master: %d\n", router->stats.n_master); dcb_printf(dcb, "\tNumber of queries forwarded to slave: %d\n", router->stats.n_slave); dcb_printf(dcb, "\tNumber of queries forwarded to all: %d\n", router->stats.n_all); if ((weightby = serviceGetWeightingParameter(router->service)) != NULL) { dcb_printf(dcb, "\tConnection distribution based on %s " "server parameter.\n", weightby); dcb_printf(dcb, "\t\tServer Target %% Connections " "Operations\n"); dcb_printf(dcb, "\t\t Global Router\n"); for (i = 0; router->servers[i]; i++) { backend = router->servers[i]; dcb_printf(dcb, "\t\t%-20s %3.1f%% %-6d %-6d %d\n", backend->backend_server->unique_name, (float)backend->weight / 10, backend->backend_server->stats.n_current, backend->backend_conn_count, backend->backend_server->stats.n_current_ops); } } } /** * Client Reply routine * * The routine will reply to client for session change with master server data * * @param instance The router instance * @param router_session The router session * @param backend_dcb The backend DCB * @param queue The GWBUF with reply data */ static void clientReply ( ROUTER* instance, void* router_session, GWBUF* writebuf, DCB* backend_dcb) { DCB* client_dcb; ROUTER_CLIENT_SES* router_cli_ses; sescmd_cursor_t* scur = NULL; backend_ref_t* bref; router_cli_ses = (ROUTER_CLIENT_SES *)router_session; CHK_CLIENT_RSES(router_cli_ses); /** * Lock router client session for secure read of router session members. * Note that this could be done without lock by using version # */ if (!rses_begin_locked_router_action(router_cli_ses)) { print_error_packet(router_cli_ses, writebuf, backend_dcb); goto lock_failed; } /** Holding lock ensures that router session remains open */ ss_dassert(backend_dcb->session != NULL); client_dcb = backend_dcb->session->client; /** Unlock */ rses_end_locked_router_action(router_cli_ses); /** * 1. Check if backend received reply to sescmd. * 2. Check sescmd's state whether OK_PACKET has been * sent to client already and if not, lock property cursor, * reply to client, and move property cursor forward. Finally * release the lock. * 3. If reply for this sescmd is sent, lock property cursor * and */ if (client_dcb == NULL) { while ((writebuf = gwbuf_consume( writebuf, GWBUF_LENGTH(writebuf))) != NULL); /** Log that client was closed before reply */ goto lock_failed; } /** Lock router session */ if (!rses_begin_locked_router_action(router_cli_ses)) { /** Log to debug that router was closed */ goto lock_failed; } bref = get_bref_from_dcb(router_cli_ses, backend_dcb); #if !defined(FOR_BUG548_FIX_ONLY) /** This makes the issue becoming visible in poll.c */ if (bref == NULL) { /** Unlock router session */ rses_end_locked_router_action(router_cli_ses); goto lock_failed; } #endif CHK_BACKEND_REF(bref); scur = &bref->bref_sescmd_cur; /** * Active cursor means that reply is from session command * execution. */ if (sescmd_cursor_is_active(scur)) { if (LOG_IS_ENABLED(LOGFILE_ERROR) && MYSQL_IS_ERROR_PACKET(((uint8_t *)GWBUF_DATA(writebuf)))) { uint8_t* buf = (uint8_t *)GWBUF_DATA((scur->scmd_cur_cmd->my_sescmd_buf)); uint8_t* replybuf = (uint8_t *)GWBUF_DATA(writebuf); size_t len = MYSQL_GET_PACKET_LEN(buf); size_t replylen = MYSQL_GET_PACKET_LEN(replybuf); char* cmdstr = strndup(&((char *)buf)[5], len-4); char* err = strndup(&((char *)replybuf)[8], 5); char* replystr = strndup(&((char *)replybuf)[13], replylen-4-5); ss_dassert(len+4 == GWBUF_LENGTH(scur->scmd_cur_cmd->my_sescmd_buf)); LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Failed to execute %s in %s:%d. %s %s", cmdstr, bref->bref_backend->backend_server->name, bref->bref_backend->backend_server->port, err, replystr))); free(cmdstr); free(err); free(replystr); } if (GWBUF_IS_TYPE_SESCMD_RESPONSE(writebuf)) { /** * Discard all those responses that have already been sent to * the client. Return with buffer including response that * needs to be sent to client or NULL. */ writebuf = sescmd_cursor_process_replies(writebuf, bref); } /** * If response will be sent to client, decrease waiter count. * This applies to session commands only. Counter decrement * for other type of queries is done outside this block. */ if (writebuf != NULL && client_dcb != NULL) { /** Set response status as replied */ bref_clear_state(bref, BREF_WAITING_RESULT); } } /** * Clear BREF_QUERY_ACTIVE flag and decrease waiter counter. * This applies for queries other than session commands. */ else if (BREF_IS_QUERY_ACTIVE(bref)) { bref_clear_state(bref, BREF_QUERY_ACTIVE); /** Set response status as replied */ bref_clear_state(bref, BREF_WAITING_RESULT); } if (writebuf != NULL && client_dcb != NULL) { /** Write reply to client DCB */ SESSION_ROUTE_REPLY(backend_dcb->session, writebuf); } /** Unlock router session */ rses_end_locked_router_action(router_cli_ses); /** Lock router session */ if (!rses_begin_locked_router_action(router_cli_ses)) { /** Log to debug that router was closed */ goto lock_failed; } /** There is one pending session command to be executed. */ if (sescmd_cursor_is_active(scur)) { bool succp; LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Backend %s:%d processed reply and starts to execute " "active cursor.", bref->bref_backend->backend_server->name, bref->bref_backend->backend_server->port))); succp = execute_sescmd_in_backend(bref); ss_dassert(succp); } else if (bref->bref_pending_cmd != NULL) /*< non-sescmd is waiting to be routed */ { int ret; CHK_GWBUF(bref->bref_pending_cmd); if ((ret = bref->bref_dcb->func.write(bref->bref_dcb, gwbuf_clone(bref->bref_pending_cmd))) == 1) { ROUTER_INSTANCE* inst = (ROUTER_INSTANCE *)instance; atomic_add(&inst->stats.n_queries, 1); /** * Add one query response waiter to backend reference */ bref_set_state(bref, BREF_QUERY_ACTIVE); bref_set_state(bref, BREF_WAITING_RESULT); } else { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Routing query \"%s\" failed.", bref->bref_pending_cmd))); } gwbuf_free(bref->bref_pending_cmd); bref->bref_pending_cmd = NULL; } /** Unlock router session */ rses_end_locked_router_action(router_cli_ses); lock_failed: return; } /** Compare nunmber of connections from this router in backend servers */ int bref_cmp_router_conn( const void* bref1, const void* bref2) { BACKEND* b1 = ((backend_ref_t *)bref1)->bref_backend; BACKEND* b2 = ((backend_ref_t *)bref2)->bref_backend; return ((1000 * b1->backend_conn_count) / b1->weight) - ((1000 * b2->backend_conn_count) / b2->weight); } /** Compare nunmber of global connections in backend servers */ int bref_cmp_global_conn( const void* bref1, const void* bref2) { BACKEND* b1 = ((backend_ref_t *)bref1)->bref_backend; BACKEND* b2 = ((backend_ref_t *)bref2)->bref_backend; return ((1000 * b1->backend_server->stats.n_current) / b1->weight) - ((1000 * b2->backend_server->stats.n_current) / b2->weight); } /** Compare relication lag between backend servers */ int bref_cmp_behind_master( const void* bref1, const void* bref2) { BACKEND* b1 = ((backend_ref_t *)bref1)->bref_backend; BACKEND* b2 = ((backend_ref_t *)bref2)->bref_backend; return ((b1->backend_server->rlag < b2->backend_server->rlag) ? -1 : ((b1->backend_server->rlag > b2->backend_server->rlag) ? 1 : 0)); } /** Compare nunmber of current operations in backend servers */ int bref_cmp_current_load( const void* bref1, const void* bref2) { SERVER* s1 = ((backend_ref_t *)bref1)->bref_backend->backend_server; SERVER* s2 = ((backend_ref_t *)bref2)->bref_backend->backend_server; BACKEND* b1 = ((backend_ref_t *)bref1)->bref_backend; BACKEND* b2 = ((backend_ref_t *)bref2)->bref_backend; return ((1000 * s1->stats.n_current_ops) - b1->weight) - ((1000 * s2->stats.n_current_ops) - b2->weight); } static void bref_clear_state( backend_ref_t* bref, bref_state_t state) { if (state != BREF_WAITING_RESULT) { bref->bref_state &= ~state; } else { int prev1; int prev2; /** Decrease waiter count */ prev1 = atomic_add(&bref->bref_num_result_wait, -1); if (prev1 <= 0) { atomic_add(&bref->bref_num_result_wait, 1); } else { /** Decrease global operation count */ prev2 = atomic_add( &bref->bref_backend->backend_server->stats.n_current_ops, -1); ss_dassert(prev2 > 0); } } } static void bref_set_state( backend_ref_t* bref, bref_state_t state) { if (state != BREF_WAITING_RESULT) { bref->bref_state |= state; } else { int prev1; int prev2; /** Increase waiter count */ prev1 = atomic_add(&bref->bref_num_result_wait, 1); ss_dassert(prev1 >= 0); /** Increase global operation count */ prev2 = atomic_add( &bref->bref_backend->backend_server->stats.n_current_ops, 1); ss_dassert(prev2 >= 0); } } /** * @node Search all RUNNING backend servers and connect * * Parameters: * @param backend_ref - in, use, out * Pointer to backend server reference object array. * NULL is not allowed. * * @param router_nservers - in, use * Number of backend server pointers pointed to by b. * * @param session - in, use * MaxScale session pointer used when connection to backend is established. * * @param router - in, use * Pointer to router instance. Used when server states are qualified. * * @return true, if at least one master and one slave was found. * * * @details It is assumed that there is only one available server. * There will be exactly as many backend references than there are * connections because all servers are supposed to be operational. It is, * however, possible that there are less available servers than expected. */ static bool connect_backend_servers( backend_ref_t* backend_ref, int router_nservers, SESSION* session, ROUTER_INSTANCE* router) { bool succp = true; /* bool is_synced_master; bool master_connected = true; */ int servers_found = 0; int servers_connected = 0; int slaves_connected = 0; int i; /* select_criteria_t select_criteria = LEAST_GLOBAL_CONNECTIONS; */ #if 0 if (router->bitvalue != 0) /*< 'synced' is the only bitvalue in rwsplit */ { is_synced_master = true; } else { is_synced_master = false; } #endif #if defined(EXTRA_SS_DEBUG) LOGIF(LT, (skygw_log_write(LOGFILE_TRACE, "Servers and conns before ordering:"))); for (i=0; ibackend_server->name, b->backend_server->port, b->backend_conn_count))); } #endif if (LOG_IS_ENABLED(LOGFILE_TRACE)) { LOGIF(LT, (skygw_log_write(LOGFILE_TRACE, "Servers and connection counts:"))); for (i=0; ibackend_conn_count, b->backend_server->stats.n_current, b->backend_server->name, b->backend_server->port, STRSRVSTATUS(b->backend_server)))); } } /*< log only */ /** * Scan server list and connect each of them. None should fail or session * can't be established. */ for (i=0; i < router_nservers; i++) { BACKEND* b = backend_ref[i].bref_backend; if (SERVER_IS_RUNNING(b->backend_server) && ((b->backend_server->status & router->bitmask) == router->bitvalue)) { servers_found += 1; /** Server is already connected */ if (BREF_IS_IN_USE((&backend_ref[i]))) { slaves_connected += 1; } /** New server connection */ else { backend_ref[i].bref_dcb = dcb_connect( b->backend_server, session, b->backend_server->protocol); if (backend_ref[i].bref_dcb != NULL) { servers_connected += 1; /** * Start executing session command * history. */ execute_sescmd_history(&backend_ref[i]); /** * When server fails, this callback * is called. * !!! Todo, routine which removes * corresponding entries from the hash * table. */ #if 0 dcb_add_callback( backend_ref[i].bref_dcb, DCB_REASON_NOT_RESPONDING, &router_handle_state_switch, (void *)&backend_ref[i]); #endif backend_ref[i].bref_state = 0; bref_set_state(&backend_ref[i], BREF_IN_USE); /** * Increase backend connection counter. * Server's stats are _increased_ in * dcb.c:dcb_alloc ! * But decreased in the calling function * of dcb_close. */ atomic_add(&b->backend_conn_count, 1); } else { succp = false; LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Unable to establish " "connection with slave %s:%d", b->backend_server->name, b->backend_server->port))); /* handle connect error */ break; } } } } /*< for */ #if defined(EXTRA_SS_DEBUG) LOGIF(LT, (skygw_log_write(LOGFILE_TRACE, "Servers and conns after ordering:"))); for (i=0; ibackend_server->name, b->backend_server->port, b->backend_conn_count))); } #endif /** * Successful cases */ if (servers_connected == router_nservers) { succp = true; if (LOG_IS_ENABLED(LT)) { for (i=0; ibackend_server), b->backend_server->name, b->backend_server->port))); } } /* for */ } } else { LOGIF(LE, (skygw_log_write( LOGFILE_ERROR, "Warning : Couldn't connect to all available " "servers. Session can't be created."))); /** Clean up connections */ for (i=0; ibackend_conn_count > 0); /** disconnect opened connections */ dcb_close(backend_ref[i].bref_dcb); bref_clear_state(&backend_ref[i], BREF_IN_USE); /** Decrease backend's connection counter. */ atomic_add(&backend_ref[i].bref_backend->backend_conn_count, -1); } } } return succp; } /** * Create a generic router session property strcture. */ static rses_property_t* rses_property_init( rses_property_type_t prop_type) { rses_property_t* prop; prop = (rses_property_t*)calloc(1, sizeof(rses_property_t)); if (prop == NULL) { goto return_prop; } prop->rses_prop_type = prop_type; #if defined(SS_DEBUG) prop->rses_prop_chk_top = CHK_NUM_ROUTER_PROPERTY; prop->rses_prop_chk_tail = CHK_NUM_ROUTER_PROPERTY; #endif return_prop: CHK_RSES_PROP(prop); return prop; } /** * Property is freed at the end of router client session. */ static void rses_property_done( rses_property_t* prop) { CHK_RSES_PROP(prop); switch (prop->rses_prop_type) { case RSES_PROP_TYPE_SESCMD: mysql_sescmd_done(&prop->rses_prop_data.sescmd); break; case RSES_PROP_TYPE_TMPTABLES: hashtable_free(prop->rses_prop_data.temp_tables); break; default: LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [rses_property_done] Unknown property type %d " "in property %p", pthread_self(), prop->rses_prop_type, prop))); ss_dassert(false); break; } free(prop); } /** * Add property to the router_client_ses structure's rses_properties * array. The slot is determined by the type of property. * In each slot there is a list of properties of similar type. * * Router client session must be locked. */ static void rses_property_add( ROUTER_CLIENT_SES* rses, rses_property_t* prop) { rses_property_t* p; CHK_CLIENT_RSES(rses); CHK_RSES_PROP(prop); ss_dassert(SPINLOCK_IS_LOCKED(&rses->rses_lock)); prop->rses_prop_rsession = rses; p = rses->rses_properties[prop->rses_prop_type]; if (p == NULL) { rses->rses_properties[prop->rses_prop_type] = prop; } else { while (p->rses_prop_next != NULL) { p = p->rses_prop_next; } p->rses_prop_next = prop; } } /** * Router session must be locked. * Return session command pointer if succeed, NULL if failed. */ static mysql_sescmd_t* rses_property_get_sescmd( rses_property_t* prop) { mysql_sescmd_t* sescmd; CHK_RSES_PROP(prop); ss_dassert(prop->rses_prop_rsession == NULL || SPINLOCK_IS_LOCKED(&prop->rses_prop_rsession->rses_lock)); sescmd = &prop->rses_prop_data.sescmd; if (sescmd != NULL) { CHK_MYSQL_SESCMD(sescmd); } return sescmd; } /** static void rses_begin_locked_property_action( rses_property_t* prop) { CHK_RSES_PROP(prop); spinlock_acquire(&prop->rses_prop_lock); } static void rses_end_locked_property_action( rses_property_t* prop) { CHK_RSES_PROP(prop); spinlock_release(&prop->rses_prop_lock); } */ /** * Create session command property. */ static mysql_sescmd_t* mysql_sescmd_init ( rses_property_t* rses_prop, GWBUF* sescmd_buf, unsigned char packet_type, ROUTER_CLIENT_SES* rses) { mysql_sescmd_t* sescmd; CHK_RSES_PROP(rses_prop); /** Can't call rses_property_get_sescmd with uninitialized sescmd */ sescmd = &rses_prop->rses_prop_data.sescmd; sescmd->my_sescmd_prop = rses_prop; /*< reference to owning property */ #if defined(SS_DEBUG) sescmd->my_sescmd_chk_top = CHK_NUM_MY_SESCMD; sescmd->my_sescmd_chk_tail = CHK_NUM_MY_SESCMD; #endif /** Set session command buffer */ sescmd->my_sescmd_buf = sescmd_buf; sescmd->my_sescmd_packet_type = packet_type; return sescmd; } static void mysql_sescmd_done( mysql_sescmd_t* sescmd) { CHK_RSES_PROP(sescmd->my_sescmd_prop); gwbuf_free(sescmd->my_sescmd_buf); memset(sescmd, 0, sizeof(mysql_sescmd_t)); } /** * All cases where backend message starts at least with one response to session * command are handled here. * Read session commands from property list. If command is already replied, * discard packet. Else send reply to client. In both cases move cursor forward * until all session command replies are handled. * * Cases that are expected to happen and which are handled: * s = response not yet replied to client, S = already replied response, * q = query * 1. q+ for example : select * from mysql.user * 2. s+ for example : set autocommit=1 * 3. S+ * 4. sq+ * 5. Sq+ * 6. Ss+ * 7. Ss+q+ * 8. S+q+ * 9. s+q+ */ static GWBUF* sescmd_cursor_process_replies( GWBUF* replybuf, backend_ref_t* bref) { mysql_sescmd_t* scmd; sescmd_cursor_t* scur; scur = &bref->bref_sescmd_cur; ss_dassert(SPINLOCK_IS_LOCKED(&(scur->scmd_cur_rses->rses_lock))); scmd = sescmd_cursor_get_command(scur); CHK_GWBUF(replybuf); /** * Walk through packets in the message and the list of session * commands. */ while (scmd != NULL && replybuf != NULL) { /** Faster backend has already responded to client : discard */ if (scmd->my_sescmd_is_replied) { bool last_packet = false; CHK_GWBUF(replybuf); while (!last_packet) { int buflen; buflen = GWBUF_LENGTH(replybuf); last_packet = GWBUF_IS_TYPE_RESPONSE_END(replybuf); /** discard packet */ replybuf = gwbuf_consume(replybuf, buflen); } /** Set response status received */ bref_clear_state(bref, BREF_WAITING_RESULT); } /** Response is in the buffer and it will be sent to client. */ else if (replybuf != NULL) { /** Mark the rest session commands as replied */ scmd->my_sescmd_is_replied = true; } if (sescmd_cursor_next(scur)) { scmd = sescmd_cursor_get_command(scur); } else { scmd = NULL; /** All session commands are replied */ scur->scmd_cur_active = false; } } ss_dassert(replybuf == NULL || *scur->scmd_cur_ptr_property == NULL); return replybuf; } /** * Get the address of current session command. * * Router session must be locked */ static mysql_sescmd_t* sescmd_cursor_get_command( sescmd_cursor_t* scur) { mysql_sescmd_t* scmd; ss_dassert(SPINLOCK_IS_LOCKED(&(scur->scmd_cur_rses->rses_lock))); scur->scmd_cur_cmd = rses_property_get_sescmd(*scur->scmd_cur_ptr_property); CHK_MYSQL_SESCMD(scur->scmd_cur_cmd); scmd = scur->scmd_cur_cmd; return scmd; } /** router must be locked */ static bool sescmd_cursor_is_active( sescmd_cursor_t* sescmd_cursor) { bool succp; ss_dassert(SPINLOCK_IS_LOCKED(&sescmd_cursor->scmd_cur_rses->rses_lock)); succp = sescmd_cursor->scmd_cur_active; return succp; } /** router must be locked */ static void sescmd_cursor_set_active( sescmd_cursor_t* sescmd_cursor, bool value) { ss_dassert(SPINLOCK_IS_LOCKED(&sescmd_cursor->scmd_cur_rses->rses_lock)); /** avoid calling unnecessarily */ ss_dassert(sescmd_cursor->scmd_cur_active != value); sescmd_cursor->scmd_cur_active = value; } /** * Clone session command's command buffer. * Router session must be locked */ static GWBUF* sescmd_cursor_clone_querybuf( sescmd_cursor_t* scur) { GWBUF* buf; ss_dassert(scur->scmd_cur_cmd != NULL); buf = gwbuf_clone(scur->scmd_cur_cmd->my_sescmd_buf); CHK_GWBUF(buf); return buf; } static bool sescmd_cursor_history_empty( sescmd_cursor_t* scur) { bool succp; CHK_SESCMD_CUR(scur); if (scur->scmd_cur_rses->rses_properties[RSES_PROP_TYPE_SESCMD] == NULL) { succp = true; } else { succp = false; } return succp; } static void sescmd_cursor_reset( sescmd_cursor_t* scur) { ROUTER_CLIENT_SES* rses; CHK_SESCMD_CUR(scur); CHK_CLIENT_RSES(scur->scmd_cur_rses); rses = scur->scmd_cur_rses; scur->scmd_cur_ptr_property = &rses->rses_properties[RSES_PROP_TYPE_SESCMD]; CHK_RSES_PROP((*scur->scmd_cur_ptr_property)); scur->scmd_cur_active = false; scur->scmd_cur_cmd = &(*scur->scmd_cur_ptr_property)->rses_prop_data.sescmd; } static bool execute_sescmd_history( backend_ref_t* bref) { bool succp; sescmd_cursor_t* scur; CHK_BACKEND_REF(bref); scur = &bref->bref_sescmd_cur; CHK_SESCMD_CUR(scur); if (!sescmd_cursor_history_empty(scur)) { sescmd_cursor_reset(scur); succp = execute_sescmd_in_backend(bref); } else { succp = true; } return succp; } /** * If session command cursor is passive, sends the command to backend for * execution. * * Returns true if command was sent or added successfully to the queue. * Returns false if command sending failed or if there are no pending session * commands. * * Router session must be locked. */ static bool execute_sescmd_in_backend( backend_ref_t* backend_ref) { DCB* dcb; bool succp; int rc = 0; sescmd_cursor_t* scur; if (BREF_IS_CLOSED(backend_ref)) { succp = false; goto return_succp; } dcb = backend_ref->bref_dcb; CHK_DCB(dcb); CHK_BACKEND_REF(backend_ref); /** * Get cursor pointer and copy of command buffer to cursor. */ scur = &backend_ref->bref_sescmd_cur; /** Return if there are no pending ses commands */ if (sescmd_cursor_get_command(scur) == NULL) { succp = false; LOGIF(LT, (skygw_log_write_flush( LOGFILE_TRACE, "Cursor had no pending session commands."))); goto return_succp; } if (!sescmd_cursor_is_active(scur)) { /** Cursor is left active when function returns. */ sescmd_cursor_set_active(scur, true); } #if defined(SS_DEBUG) LOGIF(LT, tracelog_routed_query(scur->scmd_cur_rses, "execute_sescmd_in_backend", backend_ref, sescmd_cursor_clone_querybuf(scur))); { GWBUF* tmpbuf = sescmd_cursor_clone_querybuf(scur); uint8_t* ptr = GWBUF_DATA(tmpbuf); unsigned char cmd = MYSQL_GET_COMMAND(ptr); LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [execute_sescmd_in_backend] Just before write, fd " "%d : cmd %s.", pthread_self(), dcb->fd, STRPACKETTYPE(cmd)))); gwbuf_free(tmpbuf); } #endif /*< SS_DEBUG */ switch (scur->scmd_cur_cmd->my_sescmd_packet_type) { case MYSQL_COM_CHANGE_USER: /** This makes it possible to handle replies correctly */ gwbuf_set_type(scur->scmd_cur_cmd->my_sescmd_buf, GWBUF_TYPE_SESCMD); rc = dcb->func.auth( dcb, NULL, dcb->session, sescmd_cursor_clone_querybuf(scur)); break; case MYSQL_COM_INIT_DB: { /** * Record database name and store to session. */ GWBUF* tmpbuf; MYSQL_session* data; unsigned int qlen; data = dcb->session->data; tmpbuf = scur->scmd_cur_cmd->my_sescmd_buf; qlen = MYSQL_GET_PACKET_LEN((unsigned char*)tmpbuf->start); memset(data->db,0,MYSQL_DATABASE_MAXLEN+1); strncpy(data->db,tmpbuf->start+5,qlen - 1); } /** Fallthrough */ case MYSQL_COM_QUERY: default: /** * Mark session command buffer, it triggers writing * MySQL command to protocol */ gwbuf_set_type(scur->scmd_cur_cmd->my_sescmd_buf, GWBUF_TYPE_SESCMD); rc = dcb->func.write( dcb, sescmd_cursor_clone_querybuf(scur)); break; } if (rc == 1) { succp = true; } else { succp = false; } return_succp: return succp; } /** * Moves cursor to next property and copied address of its sescmd to cursor. * Current propery must be non-null. * If current property is the last on the list, *scur->scmd_ptr_property == NULL * * Router session must be locked */ static bool sescmd_cursor_next( sescmd_cursor_t* scur) { bool succp = false; rses_property_t* prop_curr; rses_property_t* prop_next; ss_dassert(scur != NULL); ss_dassert(*(scur->scmd_cur_ptr_property) != NULL); ss_dassert(SPINLOCK_IS_LOCKED( &(*(scur->scmd_cur_ptr_property))->rses_prop_rsession->rses_lock)); /** Illegal situation */ if (scur == NULL || *scur->scmd_cur_ptr_property == NULL || scur->scmd_cur_cmd == NULL) { /** Log error */ goto return_succp; } prop_curr = *(scur->scmd_cur_ptr_property); CHK_MYSQL_SESCMD(scur->scmd_cur_cmd); ss_dassert(prop_curr == mysql_sescmd_get_property(scur->scmd_cur_cmd)); CHK_RSES_PROP(prop_curr); /** Copy address of pointer to next property */ scur->scmd_cur_ptr_property = &(prop_curr->rses_prop_next); prop_next = *scur->scmd_cur_ptr_property; ss_dassert(prop_next == *(scur->scmd_cur_ptr_property)); /** If there is a next property move forward */ if (prop_next != NULL) { CHK_RSES_PROP(prop_next); CHK_RSES_PROP((*(scur->scmd_cur_ptr_property))); /** Get pointer to next property's sescmd */ scur->scmd_cur_cmd = rses_property_get_sescmd(prop_next); ss_dassert(prop_next == scur->scmd_cur_cmd->my_sescmd_prop); CHK_MYSQL_SESCMD(scur->scmd_cur_cmd); CHK_RSES_PROP(scur->scmd_cur_cmd->my_sescmd_prop); } else { /** No more properties, can't proceed. */ goto return_succp; } if (scur->scmd_cur_cmd != NULL) { succp = true; } else { ss_dassert(false); /*< Log error, sescmd shouldn't be NULL */ } return_succp: return succp; } static rses_property_t* mysql_sescmd_get_property( mysql_sescmd_t* scmd) { CHK_MYSQL_SESCMD(scmd); return scmd->my_sescmd_prop; } static void tracelog_routed_query( ROUTER_CLIENT_SES* rses, char* funcname, backend_ref_t* bref, GWBUF* buf) { uint8_t* packet = GWBUF_DATA(buf); unsigned char packet_type = packet[4]; size_t len; size_t buflen = GWBUF_LENGTH(buf); char* querystr; char* startpos = (char *)&packet[5]; BACKEND* b; backend_type_t be_type; DCB* dcb; CHK_BACKEND_REF(bref); b = bref->bref_backend; CHK_BACKEND(b); dcb = bref->bref_dcb; CHK_DCB(dcb); be_type = BACKEND_TYPE(b); if (GWBUF_IS_TYPE_MYSQL(buf)) { len = packet[0]; len += 256*packet[1]; len += 256*256*packet[2]; if (packet_type == '\x03') { querystr = (char *)malloc(len); memcpy(querystr, startpos, len-1); querystr[len-1] = '\0'; LOGIF(LD, (skygw_log_write_flush( LOGFILE_DEBUG, "%lu [%s] %d bytes long buf, \"%s\" -> %s:%d %s dcb %p", pthread_self(), funcname, buflen, querystr, b->backend_server->name, b->backend_server->port, STRBETYPE(be_type), dcb))); free(querystr); } else if (packet_type == '\x22' || packet_type == 0x22 || packet_type == '\x26' || packet_type == 0x26 || true) { querystr = (char *)malloc(len); memcpy(querystr, startpos, len-1); querystr[len-1] = '\0'; LOGIF(LD, (skygw_log_write_flush( LOGFILE_DEBUG, "%lu [%s] %d bytes long buf, \"%s\" -> %s:%d %s dcb %p", pthread_self(), funcname, buflen, querystr, b->backend_server->name, b->backend_server->port, STRBETYPE(be_type), dcb))); free(querystr); } } gwbuf_free(buf); } /** * Return rc, rc < 0 if router session is closed. rc == 0 if there are no * capabilities specified, rc > 0 when there are capabilities. */ static uint8_t getCapabilities ( ROUTER* inst, void* router_session) { ROUTER_CLIENT_SES* rses = (ROUTER_CLIENT_SES *)router_session; uint8_t rc; if (!rses_begin_locked_router_action(rses)) { rc = 0xff; goto return_rc; } rc = rses->rses_capabilities; rses_end_locked_router_action(rses); return_rc: return rc; } /** * Execute in backends used by current router session. * Save session variable commands to router session property * struct. Thus, they can be replayed in backends which are * started and joined later. * * Suppress redundant OK packets sent by backends. * * The first OK packet is replied to the client. * Return true if succeed, false is returned if router session was closed or * if execute_sescmd_in_backend failed. */ static bool route_session_write( ROUTER_CLIENT_SES* router_cli_ses, GWBUF* querybuf, ROUTER_INSTANCE* inst, unsigned char packet_type, skygw_query_type_t qtype) { bool succp; rses_property_t* prop; backend_ref_t* backend_ref; int i; LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Session write, routing to all servers."))); backend_ref = router_cli_ses->rses_backend_ref; /** * These are one-way messages and server doesn't respond to them. * Therefore reply processing is unnecessary and session * command property is not needed. It is just routed to all available * backends. */ if (packet_type == MYSQL_COM_STMT_SEND_LONG_DATA || packet_type == MYSQL_COM_QUIT || packet_type == MYSQL_COM_STMT_CLOSE) { int rc; succp = true; /** Lock router session */ if (!rses_begin_locked_router_action(router_cli_ses)) { succp = false; goto return_succp; } for (i=0; irses_nbackends; i++) { DCB* dcb = backend_ref[i].bref_dcb; if (LOG_IS_ENABLED(LOGFILE_TRACE)) { LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Route query to %s\t%s:%d%s", (SERVER_IS_MASTER(backend_ref[i].bref_backend->backend_server) ? "master" : "slave"), backend_ref[i].bref_backend->backend_server->name, backend_ref[i].bref_backend->backend_server->port, (i+1==router_cli_ses->rses_nbackends ? " <" : "")))); } if (BREF_IS_IN_USE((&backend_ref[i]))) { rc = dcb->func.write(dcb, gwbuf_clone(querybuf)); if (rc != 1) { succp = false; } } } rses_end_locked_router_action(router_cli_ses); gwbuf_free(querybuf); goto return_succp; } /** Lock router session */ if (!rses_begin_locked_router_action(router_cli_ses)) { succp = false; goto return_succp; } if (router_cli_ses->rses_nbackends <= 0) { succp = false; goto return_succp; } /** * Additional reference is created to querybuf to * prevent it from being released before properties * are cleaned up as a part of router sessionclean-up. */ prop = rses_property_init(RSES_PROP_TYPE_SESCMD); mysql_sescmd_init(prop, querybuf, packet_type, router_cli_ses); /** Add sescmd property to router client session */ rses_property_add(router_cli_ses, prop); for (i=0; irses_nbackends; i++) { if (BREF_IS_IN_USE((&backend_ref[i]))) { sescmd_cursor_t* scur; if (LOG_IS_ENABLED(LOGFILE_TRACE)) { LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Route query to %s\t%s:%d%s", (SERVER_IS_MASTER(backend_ref[i].bref_backend->backend_server) ? "master" : "slave"), backend_ref[i].bref_backend->backend_server->name, backend_ref[i].bref_backend->backend_server->port, (i+1==router_cli_ses->rses_nbackends ? " <" : "")))); } scur = backend_ref_get_sescmd_cursor(&backend_ref[i]); /** * Add one waiter to backend reference. */ bref_set_state(get_bref_from_dcb(router_cli_ses, backend_ref[i].bref_dcb), BREF_WAITING_RESULT); /** * Start execution if cursor is not already executing. * Otherwise, cursor will execute pending commands * when it completes with previous commands. */ if (sescmd_cursor_is_active(scur)) { succp = true; LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "Backend %s:%d already executing sescmd.", backend_ref[i].bref_backend->backend_server->name, backend_ref[i].bref_backend->backend_server->port))); } else { succp = execute_sescmd_in_backend(&backend_ref[i]); if (!succp) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Failed to execute session " "command in %s:%d", backend_ref[i].bref_backend->backend_server->name, backend_ref[i].bref_backend->backend_server->port))); } } } else { succp = false; } } /** Unlock router session */ rses_end_locked_router_action(router_cli_ses); return_succp: return succp; } #if defined(NOT_USED) static bool router_option_configured( ROUTER_INSTANCE* router, const char* optionstr, void* data) { bool succp = false; char** option; option = router->service->routerOptions; while (option != NULL) { char* value; if ((value = strchr(options[i], '=')) == NULL) { break; } else { *value = 0; value++; if (strcmp(options[i], "slave_selection_criteria") == 0) { if (GET_SELECT_CRITERIA(value) == (select_criteria_t *)*data) { succp = true; break; } } } } return succp; } #endif /*< NOT_USED */ /** * Error Handler routine to resolve _backend_ failures. If it succeeds then there * are enough operative backends available and connected. Otherwise it fails, * and session is terminated. * * @param instance The router instance * @param router_session The router session * @param errmsgbuf The error message to reply * @param backend_dcb The backend DCB * @param action The action: REPLY, REPLY_AND_CLOSE, NEW_CONNECTION * @param succp Result of action. * * Even if succp == true connecting to new slave may have failed. succp is to * tell whether router has enough master/slave connections to continue work. */ static void handleError ( ROUTER* instance, void* router_session, GWBUF* errmsgbuf, DCB* backend_dcb, error_action_t action, bool* succp) { SESSION* session; ROUTER_INSTANCE* inst = (ROUTER_INSTANCE *)instance; ROUTER_CLIENT_SES* rses = (ROUTER_CLIENT_SES *)router_session; CHK_DCB(backend_dcb); /** Don't handle same error twice on same DCB */ if (backend_dcb->dcb_errhandle_called) { /** we optimistically assume that previous call succeed */ *succp = true; return; } else { backend_dcb->dcb_errhandle_called = true; } session = backend_dcb->session; if (session == NULL || rses == NULL) { *succp = false; return; } CHK_SESSION(session); CHK_CLIENT_RSES(rses); switch (action) { case ERRACT_NEW_CONNECTION: { if (!rses_begin_locked_router_action(rses)) { *succp = false; return; } /** * This is called in hope of getting replacement for * failed slave(s). */ *succp = handle_error_new_connection(inst, rses, backend_dcb, errmsgbuf); rses_end_locked_router_action(rses); break; } case ERRACT_REPLY_CLIENT: { handle_error_reply_client(session, rses, backend_dcb, errmsgbuf); *succp = false; /*< no new backend servers were made available */ break; } default: *succp = false; break; } } static void handle_error_reply_client( SESSION* ses, ROUTER_CLIENT_SES* rses, DCB* backend_dcb, GWBUF* errmsg) { session_state_t sesstate; DCB* client_dcb; backend_ref_t* bref; spinlock_acquire(&ses->ses_lock); sesstate = ses->state; client_dcb = ses->client; spinlock_release(&ses->ses_lock); /** * If bref exists, mark it closed */ if ((bref = get_bref_from_dcb(rses, backend_dcb)) != NULL) { CHK_BACKEND_REF(bref); bref_clear_state(bref, BREF_IN_USE); bref_set_state(bref, BREF_CLOSED); } if (sesstate == SESSION_STATE_ROUTER_READY) { CHK_DCB(client_dcb); client_dcb->func.write(client_dcb, gwbuf_clone(errmsg)); } } /** * Check if there is backend reference pointing at failed DCB, and reset its * flags. Then clear DCB's callback and finally try to reconnect. * * This must be called with router lock. * * @param inst router instance * @param rses router client session * @param dcb failed DCB * @param errmsg error message which is sent to client if it is waiting * * @return true if there are enough backend connections to continue, false if not */ static bool handle_error_new_connection( ROUTER_INSTANCE* inst, ROUTER_CLIENT_SES* rses, DCB* backend_dcb, GWBUF* errmsg) { SESSION* ses; int router_nservers; backend_ref_t* bref; bool succp; ss_dassert(SPINLOCK_IS_LOCKED(&rses->rses_lock)); ses = backend_dcb->session; CHK_SESSION(ses); /** * If bref == NULL it has been replaced already with another one. */ if ((bref = get_bref_from_dcb(rses, backend_dcb)) == NULL) { ss_dassert(bref != NULL); succp = false; goto return_succp; } CHK_BACKEND_REF(bref); /** * If query was sent through the bref and it is waiting for reply from * the backend server it is necessary to send an error to the client * because it is waiting for reply. */ if (BREF_IS_WAITING_RESULT(bref)) { DCB* client_dcb; client_dcb = ses->client; client_dcb->func.write(client_dcb, gwbuf_clone(errmsg)); bref_clear_state(bref, BREF_WAITING_RESULT); } bref_clear_state(bref, BREF_IN_USE); bref_set_state(bref, BREF_CLOSED); /** * Error handler is already called for this DCB because * it's not polling anymore. It can be assumed that * it succeed because rses isn't closed. */ if (backend_dcb->state != DCB_STATE_POLLING) { succp = true; goto return_succp; } /** * Remove callback because this DCB won't be used * unless it is reconnected later, and then the callback * is set again. */ dcb_remove_callback(backend_dcb, DCB_REASON_NOT_RESPONDING, &router_handle_state_switch, (void *)bref); router_nservers = router_get_servercount(inst); /** * Try to get replacement slave or at least the minimum * number of slave connections for router session. */ succp = connect_backend_servers( rses->rses_backend_ref, router_nservers, ses, inst); return_succp: return succp; } static void print_error_packet( ROUTER_CLIENT_SES* rses, GWBUF* buf, DCB* dcb) { #if defined(SS_DEBUG) if (GWBUF_IS_TYPE_MYSQL(buf)) { while (gwbuf_length(buf) > 0) { /** * This works with MySQL protocol only ! * Protocol specific packet print functions would be nice. */ uint8_t* ptr = GWBUF_DATA(buf); size_t len = MYSQL_GET_PACKET_LEN(ptr); if (MYSQL_GET_COMMAND(ptr) == 0xff) { SERVER* srv = NULL; backend_ref_t* bref = rses->rses_backend_ref; int i; char* bufstr; for (i=0; irses_nbackends; i++) { if (bref[i].bref_dcb == dcb) { srv = bref[i].bref_backend->backend_server; } } ss_dassert(srv != NULL); char* str = (char*)&ptr[7]; bufstr = strndup(str, len-3); LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Backend server %s:%d responded with " "error : %s", srv->name, srv->port, bufstr))); free(bufstr); } buf = gwbuf_consume(buf, len+4); } } else { while ((buf = gwbuf_consume(buf, GWBUF_LENGTH(buf))) != NULL); } #endif /*< SS_DEBUG */ } static int router_get_servercount( ROUTER_INSTANCE* inst) { int router_nservers = 0; BACKEND** b = inst->servers; /** count servers */ while (*(b++) != NULL) router_nservers++; return router_nservers; } #if 0 /** * Find out the number of read backend servers. * Depending on the configuration value type, either copy direct count * of slave connections or calculate the count from percentage value. */ static int rses_get_max_slavecount( ROUTER_CLIENT_SES* rses, int router_nservers) { int conf_max_nslaves; int max_nslaves; CHK_CLIENT_RSES(rses); if (rses->rses_config.rw_max_slave_conn_count > 0) { conf_max_nslaves = rses->rses_config.rw_max_slave_conn_count; } else { conf_max_nslaves = (router_nservers*rses->rses_config.rw_max_slave_conn_percent)/100; } max_nslaves = MIN(router_nservers-1, MAX(1, conf_max_nslaves)); return max_nslaves; } #endif /** * Finds out if there is a backend reference pointing at the DCB given as * parameter. * @param rses router client session * @param dcb DCB * * @return backend reference pointer if succeed or NULL */ static backend_ref_t* get_bref_from_dcb( ROUTER_CLIENT_SES* rses, DCB* dcb) { backend_ref_t* bref; int i = 0; CHK_DCB(dcb); CHK_CLIENT_RSES(rses); bref = rses->rses_backend_ref; while (irses_nbackends) { if (bref->bref_dcb == dcb) { break; } bref++; i += 1; } if (i == rses->rses_nbackends) { bref = NULL; } return bref; } /** * Calls hang-up function for DCB if it is not both running and in * master/slave/joined/ndb role. Called by DCB's callback routine. */ static int router_handle_state_switch( DCB* dcb, DCB_REASON reason, void* data) { backend_ref_t* bref; int rc = 1; ROUTER_CLIENT_SES* rses; SESSION* ses; SERVER* srv; CHK_DCB(dcb); bref = (backend_ref_t *)data; CHK_BACKEND_REF(bref); srv = bref->bref_backend->backend_server; if (SERVER_IS_RUNNING(srv) && SERVER_IS_IN_CLUSTER(srv)) { goto return_rc; } ses = dcb->session; CHK_SESSION(ses); rses = (ROUTER_CLIENT_SES *)dcb->session->router_session; CHK_CLIENT_RSES(rses); switch (reason) { case DCB_REASON_NOT_RESPONDING: dcb->func.hangup(dcb); break; default: break; } return_rc: return rc; } static sescmd_cursor_t* backend_ref_get_sescmd_cursor ( backend_ref_t* bref) { sescmd_cursor_t* scur; CHK_BACKEND_REF(bref); scur = &bref->bref_sescmd_cur; CHK_SESCMD_CUR(scur); return scur; } #if defined(PREP_STMT_CACHING) #define MAX_STMT_LEN 1024 static prep_stmt_t* prep_stmt_init( prep_stmt_type_t type, void* id) { prep_stmt_t* pstmt; pstmt = (prep_stmt_t *)calloc(1, sizeof(prep_stmt_t)); if (pstmt != NULL) { #if defined(SS_DEBUG) pstmt->pstmt_chk_top = CHK_NUM_PREP_STMT; pstmt->pstmt_chk_tail = CHK_NUM_PREP_STMT; #endif pstmt->pstmt_state = PREP_STMT_ALLOC; pstmt->pstmt_type = type; if (type == PREP_STMT_NAME) { pstmt->pstmt_id.name = strndup((char *)id, MAX_STMT_LEN); } else { pstmt->pstmt_id.seq = 0; } } CHK_PREP_STMT(pstmt); return pstmt; } static void prep_stmt_done( prep_stmt_t* pstmt) { CHK_PREP_STMT(pstmt); if (pstmt->pstmt_type == PREP_STMT_NAME) { free(pstmt->pstmt_id.name); } free(pstmt); } static bool prep_stmt_drop( prep_stmt_t* pstmt) { CHK_PREP_STMT(pstmt); pstmt->pstmt_state = PREP_STMT_DROPPED; return true; } #endif /*< PREP_STMT_CACHING */ /******************************** * This routine returns the root master server from MySQL replication tree * Get the root Master rule: * * find server with the lowest replication depth level * and the SERVER_MASTER bitval * Servers are checked even if they are in 'maintenance' * * @param servers The list of servers * @param router_nservers The number of servers * @return The Master found * */ static BACKEND *get_root_master( backend_ref_t *servers, int router_nservers) { int i = 0; BACKEND * master_host = NULL; for (i = 0; i< router_nservers; i++) { BACKEND* b; if (servers[i].bref_backend == NULL) { continue; } b = servers[i].bref_backend; if ((b->backend_server->status & (SERVER_MASTER|SERVER_MAINT)) == SERVER_MASTER) { if (master_host == NULL || (b->backend_server->depth < master_host->backend_server->depth)) { master_host = b; } } } return master_host; } /******************************** * This routine returns the root master server from MySQL replication tree * Get the root Master rule: * * find server with the lowest replication depth level * and the SERVER_MASTER bitval * Servers are checked even if they are in 'maintenance' * * @param rses pointer to router session * @return pointer to backend reference of the root master or NULL * */ static backend_ref_t* get_root_master_bref( ROUTER_CLIENT_SES* rses) { backend_ref_t* bref; backend_ref_t* candidate_bref = NULL; int i = 0; bref = rses->rses_backend_ref; while (irses_nbackends) { if ((bref->bref_backend->backend_server->status & (SERVER_MASTER|SERVER_MAINT)) == SERVER_MASTER) { if (bref->bref_backend->backend_server->status & SERVER_MASTER) { if (candidate_bref == NULL || (bref->bref_backend->backend_server->depth < candidate_bref->bref_backend->backend_server->depth)) { candidate_bref = bref; } } } bref++; i += 1; } if (candidate_bref == NULL) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Could not find master among the backend " "servers. Previous master's state : %s", STRSRVSTATUS(BREFSRV(rses->rses_master_ref))))); } return candidate_bref; } static void dbshard_process_router_options( ROUTER_INSTANCE* router, char** options) { int i; char* value; for (i = 0; options[i]; i++) { if ((value = strchr(options[i], '=')) == NULL) { LOGIF(LE, (skygw_log_write( LOGFILE_ERROR, "Warning : Unsupported " "router option \"%s\" for " "readwritesplit router.", options[i]))); } else { *value = 0; value++; #if 0 if (strcmp(options[i], "slave_selection_criteria") == 0) { c = GET_SELECT_CRITERIA(value); ss_dassert( c == LEAST_GLOBAL_CONNECTIONS || c == LEAST_ROUTER_CONNECTIONS || c == LEAST_BEHIND_MASTER || c == LEAST_CURRENT_OPERATIONS || c == UNDEFINED_CRITERIA); if (c == UNDEFINED_CRITERIA) { LOGIF(LE, (skygw_log_write( LOGFILE_ERROR, "Warning : Unknown " "slave selection criteria \"%s\". " "Allowed values are LEAST_GLOBAL_CONNECTIONS, " "LEAST_ROUTER_CONNECTIONS, " "LEAST_BEHIND_MASTER," "and LEAST_CURRENT_OPERATIONS.", STRCRITERIA(router->dbshard_config.rw_slave_select_criteria)))); } else { router->dbshard_config.rw_slave_select_criteria = c; } } #endif } } /*< for */ }