I want to show the data in MongoDB on the dashboard. I implemented it by applying the "Aggregate" . I am constantly receiving the "Query Targeting: Scanned Objects / Returned has gone about 1000" alert. How do I solve this alert? The method I thought of is as follows.
Remove the aggregation function from the dashboard: If we need the aggregation data, send a query at that time to obtain the data.
Separate aggregate functions and send queries from business logic: Divide data obtained at once through aggregate functions into multiple queries and then combine the data.
If there is a better way, I wonder if there is a common way.
CodePudding user response：
I am constantly receiving the "Query Targeting: Scanned Objects / Returned has gone about 1000" alert. How do I solve this alert?
What, specifically, are you trying to solve here?
The Query Targeting metric (and associated alert) provides general information regarding the efficiency of the workload against the cluster. It can help with identifying potential problems there, most notably when relevant indexes are missing. Some more information about the metrics and actions that you can take for it are described here.
That said, the metric itself is not perfect. The fact that the targeting ratio is high enough to trigger an alert does not necessarily mean that there is a problem or that any particular action needs to be taken. Particularly notable here is that aggregation operations can cause misleading targeting ratios depending on what types of transformations the pipeline is applying. So the existence of the alert indicates there may be some improvements that could be pursued, but it does not guarantee that there are. You can certainly take a look at the workload using the strategies described in that documentation to determine if any actions like index creation are needed in your specific situation.
The two approaches that you specifically mention in the question could be considered but they kind of don't directly address the alert itself. Certainly if these are heavy aggregations that aren't needed for the application to function then there may be good reason to consider reducing their frequency. But if they are needed by the application and they are structured to be reasonably efficient, then I would not recommend trying to make any drastic adjustments just to avoid triggering the alert. Rather it may be the case that the default query targeting alert is too low for your particular use case and workload and you may consider raising it instead.