Thanks @tutububug I think it is a good idea.
We may need your opinion /cc @iosmanthus

For now, CAS with TTL is forbidden but removing this restriction should be fine, the next few pull requests for API v2 should fix this.

@iosmanthus
Do you have any update for the issue?

@iosmanthus Do you have any update for the issue?

For now, TiKV v5.4.0 has canceled this restriction, but client-go need modify some method signature to support this feature by add a Ttl parameter to grpc request.

In go-client V2, the function CompareAndSwap will erase the expiration time of the key.
E.g

rawClient.PutWithTTL key1 value1 100
//GetKeyTTL key1 ->*ttl ==100
oldValue :=rawClient.Get key1
previousValue, ok, err := rawClient.CompareAndSwap key1 oldValue newValue
//GetKeyTTL key1 ->*ttl == 0

As far as I know, tikv splices ttl in value and uses it as a compaction filter to delete the key after the life cycle.
In tikv go-client, CompareAndSwap does not specify Ttl

        reqArgs := kvrpcpb.RawCASRequest{
		Key:   key,
		Value: newValue,
	}
	if previousValue == nil {
		reqArgs.PreviousNotExist = true
	} else {
		reqArgs.PreviousValue = previousValue
	}

	req := tikvrpc.NewRequest(tikvrpc.CmdRawCompareAndSwap, &reqArgs)
	req.MaxExecutionDurationMs = uint64(client.MaxWriteExecutionTime.Milliseconds())
	resp, _, err := c.sendReq(ctx, key, req, false)

Can I add new ttl to RawCASRequest? Also what can be done to update the value using CAS and keep the historical ttl?@iosmanthus

hi, I raise a PR #943 to fix this. @iosmanthus