提交 4db5cb7c 编写于 作者: H huolibo

docs: add request Id description

上级 9835b81e
......@@ -288,6 +288,7 @@ The configuration parameters in the URL are as follows:
- httpSocketTimeout: socket timeout in milliseconds, the default value is 5000 ms. It only takes effect when batchfetch is false.
- messageWaitTimeout: message transmission timeout in milliseconds, the default value is 3000 ms. It only takes effect when batchfetch is true.
- useSSL: connecting Securely Using SSL. true: using SSL connection, false: not using SSL connection.
- httpPoolSize: size of REST concurrent requests. The default value is 20.
**Note**: Some configuration items (e.g., locale, timezone) do not work in the REST connection.
......@@ -355,6 +356,7 @@ The configuration parameters in properties are as follows.
- TSDBDriver.HTTP_SOCKET_TIMEOUT: socket timeout in milliseconds, the default value is 5000 ms. It only takes effect when using JDBC REST connection and batchfetch is false.
- TSDBDriver.PROPERTY_KEY_MESSAGE_WAIT_TIMEOUT: message transmission timeout in milliseconds, the default value is 3000 ms. It only takes effect when using JDBC REST connection and batchfetch is true.
- TSDBDriver.PROPERTY_KEY_USE_SSL: connecting Securely Using SSL. true: using SSL connection, false: not using SSL connection. It only takes effect when using JDBC REST connection.
- TSDBDriver.HTTP_POOL_SIZE: size of REST concurrent requests. The default value is 20.
For JDBC native connections, you can specify other parameters, such as log level, SQL length, etc., by specifying URL and Properties. For more detailed configuration, please refer to [Client Configuration](/reference/config/#Client-Only).
### Priority of configuration parameters
......@@ -419,6 +421,19 @@ while(resultSet.next()){
> The query is consistent with operating a relational database. When using subscripts to get the contents of the returned fields, you have to start from 1. However, we recommend using the field names to get the values of the fields in the result set.
### execute SQL with reqId
This reqId can be used to request link tracing.
```
AbstractStatement aStmt = (AbstractStatement) connection.createStatement();
aStmt.execute("create database if not exists db", 1L);
aStmt.executeUpdate("use db", 2L);
try (ResultSet rs = aStmt.executeQuery("select * from tb", 3L)) {
Timestamp ts = rs.getTimestamp(1);
}
```
### Writing data via parameter binding
TDengine has significantly improved the bind APIs to support data writing (INSERT) scenarios. Writing data in this way avoids the resource consumption of SQL syntax parsing, resulting in significant write performance improvements in many cases.
......@@ -936,6 +951,14 @@ public class SchemalessWsTest {
</TabItem>
</Tabs>
### Schemaless with reqId
This reqId can be used to request link tracing.
```
writer.write(lineDemo, SchemalessProtocolType.LINE, SchemalessTimestampType.NANO_SECONDS, 1L);
```
### Data Subscription
The TDengine Java Connector supports subscription functionality with the following application API.
......@@ -1002,6 +1025,29 @@ Map<TopicPartition, Long> endOffsets(String topic) throws SQLException;
void seek(TopicPartition partition, long offset) throws SQLException;
```
Example usage is as follows.
```
String topic = "offset_seek_test";
Map<TopicPartition, Long> offset = null;
try (TaosConsumer<ResultBean> consumer = new TaosConsumer<>(properties)) {
consumer.subscribe(Collections.singletonList(topic));
for (int i = 0; i < 10; i++) {
if (i == 3) {
// Saving consumption position
offset = consumer.position(topic);
}
if (i == 5) {
// reset consumption to the previously saved position
for (Map.Entry<TopicPartition, Long> entry : offset.entrySet()) {
consumer.seek(entry.getKey(), entry.getValue());
}
}
ConsumerRecords<ResultBean> records = consumer.poll(Duration.ofMillis(500));
}
}
```
#### Close subscriptions
```java
......@@ -1308,3 +1354,7 @@ For additional troubleshooting, see [FAQ](../../../train-faq/faq).
## API Reference
[taos-jdbcdriver doc](https://docs.taosdata.com/api/taos-jdbcdriver)
```
```
......@@ -291,6 +291,7 @@ url 中的配置参数如下:
- httpSocketTimeout: socket 超时时间,单位 ms,默认值为 5000。仅在 batchfetch 设置为 false 时生效。
- messageWaitTimeout: 消息超时时间, 单位 ms, 默认值为 3000。 仅在 batchfetch 设置为 true 时生效。
- useSSL: 连接中是否使用 SSL。
- httpPoolSize: REST 并发请求大小,默认 20。
**注意**:部分配置项(比如:locale、timezone)在 REST 连接中不生效。
......@@ -358,6 +359,7 @@ properties 中的配置参数如下:
- TSDBDriver.HTTP_SOCKET_TIMEOUT: socket 超时时间,单位 ms,默认值为 5000。仅在 REST 连接且 batchfetch 设置为 false 时生效。
- TSDBDriver.PROPERTY_KEY_MESSAGE_WAIT_TIMEOUT: 消息超时时间, 单位 ms, 默认值为 3000。 仅在 REST 连接且 batchfetch 设置为 true 时生效。
- TSDBDriver.PROPERTY_KEY_USE_SSL: 连接中是否使用 SSL。仅在 REST 连接时生效。
- TSDBDriver.HTTP_POOL_SIZE: REST 并发请求大小,默认 20。
此外对 JDBC 原生连接,通过指定 URL 和 Properties 还可以指定其他参数,比如日志级别、SQL 长度等。更多详细配置请参考[客户端配置](/reference/config/#仅客户端适用)。
### 配置参数的优先级
......@@ -422,6 +424,19 @@ while(resultSet.next()){
> 查询和操作关系型数据库一致,使用下标获取返回字段内容时从 1 开始,建议使用字段名称获取。
### 执行带有 reqId 的 SQL
此 reqId 可用于请求链路追踪。
```
AbstractStatement aStmt = (AbstractStatement) connection.createStatement();
aStmt.execute("create database if not exists db", 1L);
aStmt.executeUpdate("use db", 2L);
try (ResultSet rs = aStmt.executeQuery("select * from tb", 3L)) {
Timestamp ts = rs.getTimestamp(1);
}
```
### 通过参数绑定写入数据
TDengine 的 JDBC 原生连接实现大幅改进了参数绑定方式对数据写入(INSERT)场景的支持。采用这种方式写入数据时,能避免 SQL 语法解析的资源消耗,从而在很多情况下显著提升写入性能。
......@@ -939,6 +954,14 @@ public class SchemalessWsTest {
</TabItem>
</Tabs>
### 执行带有 reqId 的无模式写入
此 reqId 可用于请求链路追踪。
```
writer.write(lineDemo, SchemalessProtocolType.LINE, SchemalessTimestampType.NANO_SECONDS, 1L);
```
### 数据订阅
TDengine Java 连接器支持订阅功能,应用 API 如下:
......@@ -1005,6 +1028,29 @@ Map<TopicPartition, Long> endOffsets(String topic) throws SQLException;
void seek(TopicPartition partition, long offset) throws SQLException;
```
示例代码:
```
String topic = "offset_seek_test";
Map<TopicPartition, Long> offset = null;
try (TaosConsumer<ResultBean> consumer = new TaosConsumer<>(properties)) {
consumer.subscribe(Collections.singletonList(topic));
for (int i = 0; i < 10; i++) {
if (i == 3) {
// Saving consumption position
offset = consumer.position(topic);
}
if (i == 5) {
// reset consumption to the previously saved position
for (Map.Entry<TopicPartition, Long> entry : offset.entrySet()) {
consumer.seek(entry.getKey(), entry.getValue());
}
}
ConsumerRecords<ResultBean> records = consumer.poll(Duration.ofMillis(500));
}
}
```
#### 关闭订阅
```java
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册