docs: add HTTP API for dynamic trace control

docs/reference/http-endpoints.md

@@ -111,6 +111,29 @@ This dashboard is packaged with the GreptimeDB server and provides a user-friend
 
 For more information, refer to the [how-to documentation](https://github.com/GreptimeTeam/greptimedb/blob/main/docs/how-to/how-to-change-log-level-on-the-fly.md).
 
+### Enable/Disable Trace
+
+- **Path**: `/debug/enable_trace`
+- **Methods**: `POST`
+- **Description**: Dynamically enables or disables distributed tracing at runtime.
+- **Usage**: Send `true` to enable tracing or `false` to disable tracing.
+
+Example to enable tracing:
+
+```bash
+curl --data "true" http://127.0.0.1:4000/debug/enable_trace
+# Output: trace enabled
+```
+
+Example to disable tracing:
+
+```bash
+curl --data "false" http://127.0.0.1:4000/debug/enable_trace
+# Output: trace disabled
+```
+
+For more information on tracing configuration, refer to the [tracing documentation](/user-guide/deployments-administration/monitoring/tracing.md).
+
 ### Profiling Tools
 
 - **Base Path**: `/debug/prof/`

docs/user-guide/deployments-administration/monitoring/tracing.md

@@ -9,6 +9,24 @@ GreptimeDB supports distributed tracing. GreptimeDB exports all collected spans
 
 In the [logging section](/user-guide/deployments-administration/configuration.md#logging-options) in the configuration, there are descriptions of configuration items related to tracing, [standalone.example.toml](https://github.com/GreptimeTeam/greptimedb/blob/VAR::greptimedbVersion/config/standalone.example.toml) provide a reference configuration in the logging section.
 
+## Dynamic Tracing Control
+
+GreptimeDB provides the ability to enable or disable tracing dynamically at runtime using the HTTP API without requiring a server restart. This is useful for troubleshooting production issues or temporarily enabling tracing for debugging purposes.
+
+To enable tracing:
+
+```bash
+curl --data "true" http://127.0.0.1:4000/debug/enable_trace
+# Output: trace enabled
+```
+
+To disable tracing:
+
+```bash
+curl --data "false" http://127.0.0.1:4000/debug/enable_trace
+# Output: trace disabled
+```
+
 ## Tutorial: Use Jaeger to trace GreptimeDB
 
 [Jaeger](https://www.jaegertracing.io/) is an open source, end-to-end distributed tracing system, originally developed and open sourced by Uber. Its goal is to help developers monitor and debug the request flow in complex microservice architectures.