[[kibana-troubleshooting-trace-query]]
=== Trace {es} query to the origin in {kib}
Sometimes the {es} server might be slowed down by the execution of an expensive query. Such queries are logged to {es}'s {ref}/index-modules-slowlog.html#search-slow-log[search slow log] file. But there is a problem: it's impossible to say what triggered a slow search request—a {kib} instance or a user accessing an {es} endpoint directly.
To simplify the investigation of such cases, the search slow log file includes the `x-opaque-id` header, which might provide additional information about a request if it originated from {kib}.

WARNING: At the moment, {kib} can only highlight cases where a slow query originated from a {kib} visualization, *Lens*, *Discover*, *Maps*, or *Alerting*.

For example, if a request to {es} was initiated by a Vega visualization on a dashboard, you will see the following in the slow logs:
[source,json]
----
"source": { "id": "c89d1ab3-b4a7-4920-a64a-22a910a413b0;kibana:application:dashboard:edf84fe0-e1a0-11e7-b6d5-4dc382ef7f5b;visualization:Vega:cb099a20-ea66-11eb-9425-113343a037e3" }
----

Take a closer look at the format of the string.
The id value starts with  `c89d1ab3-b4a7-4920-a64a-22a910a413b0`, which is a unique identifier of a request set by the {kib} server.
The part after the `kibana` prefix indicates that the request was triggered by *Dashboard* with id `edf84fe0-e1a0-11e7-b6d5-4dc382ef7f5b` and Vega visualization with id `cb099a20-ea66-11eb-9425-113343a037e3`.

If the provided information is not enough to identify a visualization to adjust its parameters, you can configure {kib} logs to provide a human-readable description and a link to a source of the request:
[source,yml]
----
logging:
  loggers:
    - name: execution_context
      level: debug
      appenders: [console]
----
Now, you can see the request to {es} has been initiated by the `[Logs] Unique Visitor Heatmap` visualization embedded in the `[Logs] Web Traffic` dashboard. You can navigate to the provided URL to change some parameters of the visualization.

[source,text]
----
[DEBUG][execution_context] stored the execution context: {
  "type": "application",
  "name": "dashboard",
  "id": "edf84fe0-e1a0-11e7-b6d5-4dc382ef7f5b",
  "description": "[Logs] Web Traffic","url":"/view/edf84fe0-e1a0-11e7-b6d5-4dc382ef7f5b"
  "child": {
    "type": "visualization",
    "name": "Vega",
    "id": "cb099a20-ea66-11eb-9425-113343a037e3",
    "description": "[Logs] Unique Visitor Heatmap",
    "url": "/app/visualize#/edit/cb099a20-ea66-11eb-9425-113343a037e3"
  },
}
----