MongoDB collects WiredTiger statistics once per second for diagnostics. Those places include:

• Connection stats
• Table stats for the History Store
• Table stats for special collections: the oplog, config.transactions (plus 2 indexes), and config.image_collection (plus 1 index)

The connection statistics return about 700 values, and each table returns about 300 different values.

So we're collecting about 3000 metrics per second just from WiredTiger. The more data we collect, the more it limits our retention, but also makes it hard to identify the truly useful diagnostics.

Request:

• Prune WiredTiger metrics for unneeded or redundant metrics.
• AND/OR expose an API to return a limited set of metrics that we can use for our special tables