PMM QAN MongoDB -- Explain is working randomly


The PMM QAN Explain is not working in most cases. Even for Find statements.
We have profile enabled fpr slow op only at systems lvl.
mode: slowOp
slowOpSampleRate: 0.1
slowOpThresholdMs: 200

The query is visible on the QAN dashboard and in system.profile collection. The details and Example tabs are working fine. However. explain is hanging for couple minutes and failed with the following error:

FYI: for some queries we are able to pick up the explain plan. Same cluster , different db.

Please, advise.


Hello, we are going to revisit QAN explain for MongoDB in 2.43.0.
Could you share queries that doesn’t work?

Here is couple examples:
FIND scheduled-buy-rates Applied,Effective
FIND transactions DeliveryMethod.Payer.AlternativeId,Status,Updated

From Pmm the following is visible:
FIND scheduled-buy-rates Effective,Revisions.0

Same query in system.profile

        "find" : "scheduled-buy-rates",
        "filter" : {
                "Effective" : {
                        "$gte" : ISODate("0001-01-01T00:00:00Z"),
                        "$lte" : ISODate("2024-05-30T05:42:31Z")
                "Applied" : null
        "projection" : {
                "Revisions" : 0
        "skip" : 0,
        "limit" : 2147483647,
        "readConcern" : {
                "level" : "majority"
        "$db" : "pricing-qa",
        "$readPreference" : {
                "mode" : "primaryPreferred"
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