no mycat database selected

使用mycat做读写分离，数据库的权限配置都对，但是一访问程序就报错：no mycat database selected；从报错信息上看是因为没有选中数据库导致的，如果不使用mycat就没有这个错，经排查发现是因jdbc连接串中没有设置默认的库导致的。

有问题的配置

url=jdbc:mysql://127.0.0.1:3306?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true

正确的配置,在端口后边任意一个使用到的数据库名称即可

url=jdbc:mysql://127.0.0.1:3306/voole_sysmgr?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true

源码中根据当前schame判断连接是否存在，问题应该出自这里。

public void execute(String sql, int type) {// 连接状态检查if (this.isClosed()) {LOGGER.warn("ignore execute ,server connection is closed " + this);return;}// 事务状态检查if (txInterrupted) {writeErrMessage(ErrorCode.ER_YES, "Transaction error, need to rollback." + txInterrputMsg);return;}// 检查当前使用的DB        //@1String db = this.schema;boolean isDefault = true;if (db == null) {db = SchemaUtil.detectDefaultDb(sql, type);if (db == null) {writeErrMessage(ErrorCode.ERR_BAD_LOGICDB, "No MyCAT Database selected");return;}isDefault = false;}                // @2 start // 兼容PhpAdmin's, 支持对MySQL元数据的模拟返回//// TODO: 2016/5/20 支持更多information_schema特性if (ServerParse.SELECT == type && db.equalsIgnoreCase("information_schema")) {MysqlInformationSchemaHandler.handle(sql, this);return;}if (ServerParse.SELECT == type && sql.contains("mysql") && sql.contains("proc")) {SchemaUtil.SchemaInfo schemaInfo = SchemaUtil.parseSchema(sql);if (schemaInfo != null && "mysql".equalsIgnoreCase(schemaInfo.schema)&& "proc".equalsIgnoreCase(schemaInfo.table)) {// 兼容MySQLWorkbenchMysqlProcHandler.handle(sql, this);return;}}SchemaConfig schema = MycatServer.getInstance().getConfig().getSchemas().get(db);if (schema == null) {writeErrMessage(ErrorCode.ERR_BAD_LOGICDB, "Unknown MyCAT Database '" + db + "'");return;}// fix navicat SELECT STATE AS `State`, ROUND(SUM(DURATION),7) AS// `Duration`, CONCAT(ROUND(SUM(DURATION)/*100,3), '%') AS `Percentage`// FROM INFORMATION_SCHEMA.PROFILING WHERE QUERY_ID= GROUP BY STATE// ORDER BY SEQif (ServerParse.SELECT == type && sql.contains(" INFORMATION_SCHEMA.PROFILING ")&& sql.contains("CONCAT(ROUND(SUM(DURATION)/")) {InformationSchemaProfiling.response(this);return;}  //@2 end/* * 当已经设置默认schema时，可以通过在sql中指定其它schema的方式执行 相关sql，已经在mysql客户端中验证。 * 所以在此处增加关于sql中指定Schema方式的支持。 */if (isDefault && schema.isCheckSQLSchema() && isNormalSql(type)) {SchemaUtil.SchemaInfo schemaInfo = SchemaUtil.parseSchema(sql);if (schemaInfo != null && schemaInfo.schema != null && !schemaInfo.schema.equals(db)) {SchemaConfig schemaConfig = MycatServer.getInstance().getConfig().getSchemas().get(schemaInfo.schema);if (schemaConfig != null)schema = schemaConfig;}}    //@3routeEndExecuteSQL(sql, type, schema);   //@4}