What's this?

Temproraly solving some mvcc leveldb problem without which resolve lock will not work for splitted regions.

Can it print a lot?

We could remove this log.

It's complex. I want to confirm Does it fail with the always cached version?

I've tested without cache change, it will fail with error reported from admin check statement. Could be treated as a reproducing case in unit-test, we need also add cases in ticase I think.

Seems it never changes.

We could remove this log.

Seems in the current code, we don't cache when the primary lock is prewrite lock type. Can we move this logic to where saveResolved originally was (L579)? We have more information there. And we can even cache it when the primary lock is committed with a positive ts.

If we want to cache all results, we need to change kvproto.

And we can even cache it when the primary lock is committed with a positive ts.

It seldom happens...

We could not get the lock type for the lock we met in the original place, which is needed for the cache check. We could add back the saving logic for commited transaction in the original place?

okay i think it's optional as youjiali1995 says this case seldom happens.

@youjiali1995 @sticnarf
In the previous diff the resolved cache would be checked everytime which is not necessary, I put back the cache fill related logic to its original place, PTAL again, thx

How about to make this failpoint more general (eg. like the following) so that we can either disable it by return("skip") or delay it by sleep(1000)?

failpoint.Inject("beforeCommitSecondaries", func(v failpoint.Value) {
	if s, ok := v.(string); !ok {
	} else if s == "skip" {
		failpoint.Return()
	}
})

Could you combine TxnID and Primary's LockForUpdateTS together as the key of LockResolver.resolved as a cache. I'm worried about the performance impact of removing the cache.

The impact now is resolving pessimistic locks whose primary lock is prewrite lock type, will need more check_txn_status calls, we could make the returnd status certain or not in the future to lower the risk.