linrrzqqq opened a new pull request, #57941:
URL: https://github.com/apache/doris/pull/57941
### What problem does this PR solve?
Issue Number: close #xxx
Related PR: #xxx
Problem Summary:
The `hour(from_unixtime(xxx))` function is slow because `from_unixtime`needs
to extract the full yyyy-MM-dd HH:mm:ss format from the timestamp, which is not
necessary. By calculating only the required fields directly from the timestamp,
the process can be significantly faster.
Add a function `hour_from_unixtime(ts)` to extract the hour from a unix
timestamp, which is timezone aware.
Implementation:
1. Lookup the timezone offset with cctz library
2. Calculate the hour from local unixtime
```cpp
int64_t local_unixtime = unixtime + timezone.lookup_offset(unixtime);
int hour = (local_unixtime % (24 * 3600)) / 3600
```
### Release note
None
### Check List (For Author)
- Test <!-- At least one of them must be included. -->
- [x] Regression test
- [ ] Unit Test
- [ ] Manual test (add detailed scripts or steps below)
- [ ] No need to test or manual test. Explain why:
- [ ] This is a refactor/code format and no logic has been changed.
- [ ] Previous test can cover this change.
- [ ] No code files have been changed.
- [ ] Other reason <!-- Add your reason? -->
- Behavior changed:
- [x] No.
- [ ] Yes. <!-- Explain the behavior change -->
- Does this need documentation?
- [ ] No.
- [ ] Yes. <!-- Add document PR link here. eg:
https://github.com/apache/doris-website/pull/1214 -->
### Check List (For Reviewer who merge this PR)
- [ ] Confirm the release note
- [ ] Confirm test cases
- [ ] Confirm document
- [ ] Add branch pick label <!-- Add branch pick label that this PR should
merge into -->
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