Merge branch 'MAX-324' of https://github.com/mariadb-corporation/MaxScale into MAX-324

Conflicts:
	server/modules/include/dbshard.h
	server/modules/routing/dbshard/dbshard.c

server/modules/include/dbshard.h

@@ -1,5 +1,28 @@
 #ifndef _DBSHARDROUTER_H
 #define _DBSHARDROUTER_H
+/*
+ * 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
+ */
+
+/**
+ * @file router.h - The dbshard router module heder file
+ *
+ * @verbatim
+ * Revision History
  *
  * See GitHub https://github.com/skysql/MaxScale
  *
@@ -293,9 +316,14 @@ typedef struct router_instance {
 	unsigned int	        bitvalue;    /*< Required value of server->status   */
 	ROUTER_STATS            stats;       /*< Statistics for this router         */
         struct router_instance* next;        /*< Next router on the list            */
+	bool			available_slaves; /*< The router has some slaves available */
+	HASHTABLE* dbnames_hash; /** Hashtable containing the database names and where to find them */
 } ROUTER_INSTANCE;
 
 #define BACKEND_TYPE(b) (SERVER_IS_MASTER((b)->backend_server) ? BE_MASTER :    \
         (SERVER_IS_SLAVE((b)->backend_server) ? BE_SLAVE :  BE_UNDEFINED));
 
+void* dbnames_hash_init(BACKEND** backends);
+bool update_dbnames_hash(BACKEND** backends, HASHTABLE* hashtable);
+
 #endif /*< _DBSHARDROUTER_H */

server/modules/routing/CMakeLists.txt

@@ -6,6 +6,10 @@ add_library(testroute SHARED testroute.c)
 target_link_libraries(testroute log_manager utils)
 install(TARGETS testroute DESTINATION modules)
 
+add_library(dbshard SHARED dbshard/dbshard.c)
+target_link_libraries(dbshard log_manager utils query_classifier)
+install(TARGETS dbshard DESTINATION modules)
+
 add_library(readconnroute SHARED readconnroute.c)
 target_link_libraries(readconnroute log_manager utils)
 install(TARGETS readconnroute DESTINATION modules)

server/modules/routing/dbshard/dbshard.c

@@ -233,6 +233,11 @@ static void tracelog_routed_query(
         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,
@@ -311,6 +316,153 @@ static void* hfree(void* fval)
 }
 
 
+/**
+ * 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 = 5;
+	const unsigned int read_timeout = 2;
+	bool rval = true;
+	SERVER* server;
+	MYSQL* handle;
+	MYSQL_RES* result;
+	MYSQL_ROW row;
+	int i, rc, numfields;
+	
+	for(i = 0;backends[i] && rval;i++){
+
+	handle = mysql_init(NULL);
+
+	if(handle == NULL){
+		LOGIF(LE, (skygw_log_write_flush(LOGFILE_ERROR,"Error: Failed to initialize MySQL handle.")));
+	    continue;
+	}
+
+	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 (mysql_real_connect(handle,
+							   server->name,
+							   server->monuser,
+							   server->monpw,
+							   NULL,
+							   server->port,
+							   NULL,
+							   0) == NULL)
+			{
+				LOGIF(LE, (skygw_log_write_flush(
+												 LOGFILE_ERROR,
+												 "Error: Failed to connect to backend server '%s'.",server->name)));	
+			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 execute query in backend server '%s'.",server->name)));
+			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);
+				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){
+
+					/*Check if the failure was due to a duplicate value*/
+					if(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: Duplicate value found.")));
+					}
+					rval = false;
+					free(dbnm);
+					free(servnm);					
+				}
+			}
+		
+	cleanup:
+		
+		if(result){
+			mysql_free_result(result);
+		}
+		result = NULL;
+		mysql_close(handle);		
+	}
+
+	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(32,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;
+	}
+
+	return htbl;
+	
+}
+
 /**
  * Implementation of the mandatory version entry point
  *
@@ -574,11 +726,11 @@ createInstance(SERVICE *service, char **options)
 	 * is used if any.
 	 */
         router->dbshard_version = service->svc_config_version;
-	
+		refreshInstance(router, NULL);
 	/**
 	 * Get hashtable which includes dbname,backend pairs
 	 */
-	router->dbnames_hash = dbnames_hash_init(router->servers);
+		router->dbnames_hash = (HASHTABLE*)dbnames_hash_init(router->servers);
         /**
          * We have completed the creation of the router data, so now
          * insert this router into the linked list of routers
@@ -4252,11 +4404,54 @@ static backend_ref_t* get_root_master_bref(
 }
 
 
+static void dbshard_process_router_options(
+        ROUTER_INSTANCE* router,
+        char**           options)
+{
+        int               i;
+        char*             value;
+        select_criteria_t c;
         
+        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 (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->rwsplit_config.rw_slave_select_criteria))));
+                                }
+                                else
+                                {
+                                        router->rwsplit_config.rw_slave_select_criteria = c;
+                                }
+                        }
+                }
+        } /*< for */
+}