Add connection lifetime config samples

Signed-off-by: Xiaoguang Sun <[email protected]>

Author: sunxiaoguang

develop/dev-guide-connection-parameters.md

@@ -34,6 +34,35 @@ It is a common practice that the connection pool size is well adjusted according
 
 The application needs to return the connection after finishing using it. It is recommended that the application uses the corresponding connection pool monitoring (such as **metricRegistry**) to locate connection pool issues in time.
 
+### Configure the lifetime of connections
+
+When a TiDB server is shut down or restarted for maintenance or due to hardware failure, client connections may be reset, leading to application disruptions. It is recommended to close and reconnect long-running database connections at least once a day.
+
+<SimpleTab>
+<div label="HikariCP">
+
+- **maxLifetime**: The maximum lifetime of a connection in the pool.
+
+</div>
+
+<div label="tomcat-jdbc">
+
+- **maxAge**: The maximum lifetime of a connection in the pool.
+
+</div>
+
+<div label="c3p0">
+
+- **maxConnectionAge**: The maximum lifetime of a connection in the pool.
+
+</div>
+
+<div label="dbcp">
+- **maxConnLifetimeMillis**: The maximum lifetime of a connection in the pool.
+
+</div>
+</SimpleTab>
+
 ### Probe configuration
 
 The connection pool maintains persistent connections from clients to TiDB as follows:
@@ -293,4 +322,4 @@ Ask the community on [Discord](https://discord.gg/DQZ2dy3cuc?utm_source=doc) or
 
 Ask the community on [Discord](https://discord.gg/DQZ2dy3cuc?utm_source=doc) or [Slack](https://slack.tidb.io/invite?team=tidb-community&channel=everyone&ref=pingcap-docs), or [submit a support ticket](https://tidb.support.pingcap.com/).
 
-</CustomContent>
+</CustomContent>

tidb-cloud/serverless-limitations.md

@@ -20,7 +20,7 @@ We are constantly filling in the feature gaps between {{{ .starter }}}/Essential
 
 ### Connection
 
-- Database client connections that are held open longer than 30 minutes may be terminated unexpectedly. To avoid this, start with a 5-minute maximum connection lifetime and increase it if you observe a negative impact on tail latency.
+- Database client connections that remain open for more than 30 minutes may be terminated unexpectedly. When a server is shut down or restarted, client connections can be reset after this duration, resulting in application disruptions. It is recommended to start with a maximum connection lifetime of 15 minutes and extend it if you notice a negative impact on tail latency. Refer to the [recommended settings for connection pools](/develop/dev-guide-connection-parameters.md#connection-pools-and-connection-parameters) for additional information.
 - Only [Public Endpoint](/tidb-cloud/connect-via-standard-connection-serverless.md) and [Private Endpoint](/tidb-cloud/set-up-private-endpoint-connections-serverless.md) can be used. You cannot use [VPC Peering](/tidb-cloud/set-up-vpc-peering-connections.md) to connect to {{{ .starter }}} or {{{ .essential }}} clusters. 
 - No [IP Access list](/tidb-cloud/configure-ip-access-list.md) support.