[exporter/clickhouse] Add support for short data TTL

[Hazuwall]

Component(s)

exporter/clickhouse

Is your feature request related to a problem? Please describe.

I want to save disk space by reducing retention to several hours, which is more than enough for me. I cannot achieve this without manual schema migration or complex workarounds.

Describe the solution you'd like

It would be great to have the possibility to configure TTL by using a ttl_hours parameter instead of ttl_days if the duration is less than a day.

Describe alternatives you've considered

I have considered more general alternative approaches:

• Allow the user to use a custom script for table creation. This seems like overkill and is not very convenient for both users and developers.
• Add the TTL expression to the parameters. As I understand, this is not enough because the partition expression also needs to be changed. Additionally, I cannot imagine a use case for TTL other than days/hours.

Additional context

No response

[github-actions]

Pinging code owners:

• exporter/clickhouse: @hanjm @dmitryax @Frapschen

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[dmitryax]

This makes sense. I think TTL should be time.Duration field, not the days count. @Hazuwall do you have a chance to apply this change yourself? We would need to deprecate ttl_days (don't delete it for now) in favor of the new ttl option.

[Hazuwall]

I will give it a try in my spare time. To be honest, I have limited experience in contributing to open-source projects and working with Golang, so it may take some time.

[dmitryax]

Timeline is not a problem. I don't think anyone else is interested in this. I can still put a help wanted label, maybe someone else can pick it up. Once you have time, please take a look at https://github.com/open-telemetry/opentelemetry-collector/blob/main/CONTRIBUTING.md before starting to work on it.

[leartbeqiraj1]

I will make this change within this week, or next week at the latest.