If allow readMajority, snapshotManager will be opened on mongo-wt or mongorocks.
We assume there are 2 secondaries after a primary.
One snapshot(exactly saying, one in snapshotmanager, one in repl module, about 8+8*2 = 24 bytes) will be held for each oplog entry in memory,
If both of the two secondaries are almost stale(but still catches with primary), snapshot will not be committed, neither memory nor disk can not be released, it can be quite dangerous.Am I right?

My question is:
1) If both secondaries are stale, but primary still alives and keeps writing. More snapshots will be generated, Does it lead to an oom finally ?
2) Plz figure out the misunderstandings above, thanks.