docs: fast write example for java and python (#15171)

* docs: monitor numberOfTable in FaskWriteExample.java

* docs: add note to python example

docs/examples/java/src/main/java/com/taos/example/highvolume/DataBaseMonitor.java

@@ -44,4 +44,20 @@ public class DataBaseMonitor {
         }
         return null;
     }
+
+    /**
+     * show test.stables;
+     *
+     *               name              |      created_time       | columns |  tags  |   tables    |
+     * ============================================================================================
+     *  meters                         | 2022-07-20 08:39:30.902 |       4 |      2 |      620000 |
+     */
+    public  Long getTableCount() throws SQLException {
+        if (!stmt.isClosed()) {
+            ResultSet result = stmt.executeQuery("show test.stables");
+            result.next();
+            return result.getLong(5);
+        }
+        return null;
+    }
 }
\ No newline at end of file

docs/examples/java/src/main/java/com/taos/example/highvolume/FastWriteExample.java

@@ -13,7 +13,7 @@ import java.util.concurrent.BlockingQueue;
 public class FastWriteExample {
     final static Logger logger = LoggerFactory.getLogger(FastWriteExample.class);
 
-    final static int taskQueueCapacity = 10000000;
+    final static int taskQueueCapacity = 1000000;
     final static List<BlockingQueue<String>> taskQueues = new ArrayList<>();
     final static List<ReadTask> readTasks = new ArrayList<>();
     final static List<WriteTask> writeTasks = new ArrayList<>();
@@ -61,8 +61,9 @@ public class FastWriteExample {
         long lastCount = 0;
         while (true) {
             Thread.sleep(10000);
+            long numberOfTable = databaseMonitor.getTableCount();
             long count = databaseMonitor.count();
-            logger.info("count={} speed={}", count, (count - lastCount) / 10);
+            logger.info("numberOfTable={} count={} speed={}", numberOfTable, count, (count - lastCount) / 10);
             lastCount = count;
         }
     }

docs/zh/07-develop/03-insert-data/05-high-volume.md

@@ -428,6 +428,12 @@ SQLWriter 类封装了拼 SQL 和写数据的逻辑。所有的表都没有提
 
 </details>
 
+:::note
+使用 Python 连接器多进程连接 TDengine 的时候，有一个限制：不能在父进程中建立连接，所有连接只能在子进程中创建。
+如果在父进程中创建连接，子进程再创建连接就会一直阻塞。这是个已知问题。
+
+:::
+
 </TabItem>
 </Tabs>