See the attached stack dump file.

KVDatabaseCatalogEntry::sizeOnDisk is called under the KVDatabaseCatalogEntry::_collectionsLock in thread #16, but we are under a WT transaction there (i.e. snapshot is being held).

The code which already holds the _collectionsLock (threads #13 or #15) is stuck on eviction. Eviction cannot proceed because of the transaction started by thread #16, but thread #16 cannot make progress because it's stuck on the _collectionsLock.

The solution would be to not call WT methods under this mutex.

I believe the list of collections should be stable, because we are under the DB IX lock and adding a collection requires DB X lock, so we can completely get rid of this mutex.