Primary replica slow to download a single document

[Jason_Tran]

Hi @Nick_Grealy,

@Nick_Grealy

The same command however in my mock production (M5, same document, but about 10x the number of documents), is taking 2 minutes to fetch a single document!

Firstly - thanks for providing the detailed summary It’s definitely interesting (just from an initial glance) for the 120 second document fetch using _id on the M5 tier cluster.

@Nick_Grealy

 executionStats: {
    executionSuccess: true,
    nReturned: 1,
    executionTimeMillis: 1

Based off the "executionStats", it shows 1ms. Just to provide some extra context so I can better understand the issue, can you advise how you are measuring the 120 seconds / 2 minutes from the M5 tier cluster? Additionally, are you seeing this 120 seconds query time when you are running the same find command when connecting to the M5 tier cluster via mongosh shell?

Lastly, has this behaviour always been experienced on this M5 tier cluster? Or is this something more recent? I am thinking that perhaps exceeding the data transfer limitation may be a possibility here.

Look forward to hearing from you.

Regards,
Jason