Summary

The collStats command currently returns WiredTiger data source statistics for a particular file along with the rest of the collection/index information. However, only a subset of these data source metrics (ones that are considered fast) are populated in the result. This is because we use the statistics=(fast) config in both the connection and the statistics cursor. We should add a configuration to the collStats command or something similar in order to query all of the wiredtiger data source metrics. This requires using the statistics=(all) configuration in both the connection and the statistics cursor.

Note: This will likely be much slower particularly for large files than when using the fast config so it should not be used by default.

Motivation

The B-tree statistics could be helpful in customer cases in order to determine tree shape/layout and page stat information such as number of leaf, internal or overflow pages.

Links

MongoDB stat cursor usage
wiredtiger connection configuration
wiredtiger stat cursor configuration parsing