function RawCAS do not expose parameter 'ttl'

[tutububug]

in kvproto project, RawCASRequest defined and include the 'ttl' member, and tikv-server also deal the request with 'ttl' semantic.
why does not exposed it to the client api? CAS with ttl seems very useful in many cases.

[disksing]

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

[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.

[dbjoa]

@iosmanthus
Do you have any update for the issue?

[iosmanthus]

@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.

[tutububug]

ok, thank you. I had forked repository of client-go to modify method signature.

…

-------- 原始邮件 -------- 发件人： iosmanthus ***@***.***> 日期： 2022年2月22日周二 15:58 收件人： tikv/client-go ***@***.***> 抄送： tutububug ***@***.***>, Mention ***@***.***> 主 题： Re: [tikv/client-go] function RawCAS do not expose parameter 'ttl' (Issue #371) @iosmanthus<https://github.com/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. ― Reply to this email directly, view it on GitHub<#371 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AJU3HUGMHQATOYRGUG7JEO3U4M62TANCNFSM5H2FF3ZA>. Triage notifications on the go with GitHub Mobile for iOS<https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android<https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you were mentioned.Message ID: ***@***.***>

[wenlive]

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

[tutububug]

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