Support collStats and indexStats on AWS DocDB

[MatthiasDrewsCS]

Is your feature request related to a problem? Please describe.
The MongoDB exporter works fine with AWS DocDB. However the collStats and indexStats collectors are failing. The reason seems to be a query which fails on AWS side:

2026-03-30T14:36:59.957272165Z time=2026-03-30T14:36:59.957Z level=ERROR source=indexstats_collector.go:82 msg="cannot list collections" collector=indexstats error="cannot list the collections for \"database1\": cannot get the list of collections for discovery: Field 'type' is currently not supported"

This happens both with --discovering-mode, or --no-discovering-mode with --mongodb.collstats-colls and --mongodb.indexstats-colls

Describe the solution you'd like
The MongoDB exporter should be able to export collStats and indexStats from a AWS DocDB, at least with --no-discovering-mode

[tarteens]

I'm also interesting in this, after some debugging , i found that i needed to comment those part to make it work.

--- a/exporter/collstats_collector.go
+++ b/exporter/collstats_collector.go
@@ -104,7 +104,8 @@ func (d *collstatsCollector) collect(ch chan<- prometheus.Metric) {
                                Key: "$collStats",
                                Value: bson.M{
                                        // TODO: PMM-9568 : Add support to handle histogram metrics
-                                       "latencyStats": bson.M{"histograms": false},
+                                       // This is not supported by DocDB
+                                       // "latencyStats": bson.M{"histograms": false},
                                        "storageStats": bson.M{"scale": 1},
                                },
                        },

--- a/exporter/collstats_collector.go
+++ b/exporter/collstats_collector.go
@@ -104,7 +104,8 @@ func (d *collstatsCollector) collect(ch chan<- prometheus.Metric) {
                                Key: "$collStats",
                                Value: bson.M{
                                        // TODO: PMM-9568 : Add support to handle histogram metrics
-                                       "latencyStats": bson.M{"histograms": false},
+                                       // This is not supported by DocDB
+                                       // "latencyStats": bson.M{"histograms": false},
                                        "storageStats": bson.M{"scale": 1},
                                },
                        },

i we can have an option or a better way to make it compatible with DocDB..

[github-actions]

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[eloo-abi]

/fresh