docs fix for doubleMean description (#11513)
* fix for doubleMean description
* include quantile aggregator description from Suneet
* update hyperlink to quantiles aggregator
diff --git a/docs/querying/aggregations.md b/docs/querying/aggregations.md
index e783d2d..fe3edc0 100644
--- a/docs/querying/aggregations.md
+++ b/docs/querying/aggregations.md
@@ -126,7 +126,9 @@
### `doubleMean` aggregator
-Computes and returns arithmetic mean of a column values as 64 bit float value. This is a query time aggregator only and should not be used during indexing.
+Computes and returns arithmetic mean of a column values as 64 bit float value. `doubleMean` is a query time aggregator only. It is not available for indexing.
+
+To accomplish mean aggregation on ingestion, refer to the [Quantiles aggregator](../development/extensions-core/datasketches-quantiles.md#aggregator) from the DataSketches extension.
```json
{ "type" : "doubleMean", "name" : <output_name>, "fieldName" : <metric_name> }
