refactor(types): spilt timestamp to timestamp and timestampnano

[xxhZs]

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What's changed and what's your intention?

in #19827, we support timestamp with nano, but we can't support interval with nano in a similar way. So we have to introduce the new type, and correspondingly, we should implement the new type timestamp_nano, so we distinguish between timestamp_nano and timestamp in this pr

Checklist

• I have written necessary rustdoc comments.
• I have added necessary unit tests and integration tests.
• I have added test labels as necessary.
• I have added fuzzing tests or opened an issue to track them.
• My PR contains breaking changes.
• My PR changes performance-critical code, so I will run (micro) benchmarks and present the results.
• My PR contains critical fixes that are necessary to be merged into the latest release.

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Release note

[gru-agent]

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[chenzl25]

After this PR, what's the precision of the timestamp type?

[xxhZs]

After this PR, what's the precision of the timestamp type?

timestamp -> 6 us
timestampnano -> 9 ns

[chenzl25]

After this PR, what's the precision of the timestamp type?

timestamp -> 6 us timestampnano -> 9 ns

I remembered timestamp should already be nano precision. Does it mean this is a breaking change?

[xiangjinwu]

I remembered timestamp should already be nano precision. Does it mean this is a breaking change?

It was also a breaking change regarding the extract function when we upgraded the precision in #19827 - same expression returns different value in different version: 1.234567 vs 1.234567000.

[xxhZs]

It was also a breaking change regarding the extract function when we upgraded the precision in #19827 - same expression returns different value in different version: 1.234567 vs 1.234567000.

Yes. There should be no compatibility issues with this pr, but it will make some user behavior changes

[chenzl25]

I remembered timestamp should already be nano precision. Does it mean this is a breaking change?

It was also a breaking change regarding the extract function when we upgraded the precision in #19827 - same expression returns different value in different version: 1.234567 vs 1.234567000.

I am ok with this PR to keep the timestamp with us precision and introduce a new timestampnano type to introduce nano precision timestamp. It can make the code clearer and it doesn't make too much sense to let timestamp and timestampnano have the same precision. What do you think @xiangjinwu

[xiangjinwu]

I agree. I meant this breaking change is acceptable and can actually "fix"/revert a previous breaking change.

[chenzl25]

Considering other system nano timestamp type naming conventions, I think it's better to use timestamp_ns instead of timestampnano
https://arc.net/l/quote/xaiqjmve
https://duckdb.org/docs/sql/data_types/timestamp.html