code: private boolean dumpTableMeta(MysqlConnection connection, final CanalEventFilter filter) {
          try {
              ResultSetPacket packet = connection.query("show databases");
              List<String> schemas = new ArrayList<String>();
              for (String schema : packet.getFieldValues()) {
                  schemas.add(schema);
              }
  
              for (String schema : schemas) {
                  // filter views
                  packet = connection.query("show full tables from `" + schema + "` where Table_type = 'BASE TABLE'");
                  List<String> tables = new ArrayList<String>();
                  for (String table : packet.getFieldValues()) {
                      if ("BASE TABLE".equalsIgnoreCase(table)) {
                          continue;
                      }
                      String fullName = schema + "." + table;
                      if (blackFilter == null || !blackFilter.filter(fullName)) {
                          if (filter == null || filter.filter(fullName)) {
                              tables.add(table);
                          }
                      }
                  }
  
                  if (tables.isEmpty()) {
                      continue;
                  }
  
                  StringBuilder sql = new StringBuilder();
                  for (String table : tables) {
                      sql.append("show create table `" + schema + "`.`" + table + "`;");
                  }
  
                  List<ResultSetPacket> packets = connection.queryMulti(sql.toString());
                  for (ResultSetPacket onePacket : packets) {
                      if (onePacket.getFieldValues().size() > 1) {
                          String oneTableCreateSql = onePacket.getFieldValues().get(1);
                          memoryTableMeta.apply(INIT_POSITION, schema, oneTableCreateSql, null);
                      }
                  }
              }
  
              return true;
          } catch (IOException e) {
              throw new CanalParseException(e);
          }
      }
docs: 初始化的时候dump一下表结构