freemandealer opened a new pull request, #48687:
URL: https://github.com/apache/doris/pull/48687
The initialization of the file cache involves asynchronous loading logic and
synchronous upgrade directories. The latter mainly handles the conversion from
version1 to version2 format and some fallback logic for problematic
directories, which involves a large number of directory traversals and can be
very slow.
Previously, in PR #44429, we changed the initialization of multiple cache
directories from parallel to serial to avoid the disorder caused by concurrent
initialization, which led to a long cache initialization time and affected the
startup speed of the BE.
We found that the upgrade directory is only meaningful during upgrades and
does not need to be executed on every restart. Therefore, if we detect that the
version file has been successfully written, we consider the cache directory to
have completed the upgrade and skip these redundant directory traversals
Of course, we could further optimize the directory traversal process to make
it asynchronous and not block the BE startup. However, this would result in
three concurrent operations on the file system: asynchronous loading,
asynchronous updating, and lazy loading on query. This would increase code
complexity, the likelihood of errors, and the difficulty of troubleshooting.
Considering that old clusters are not very common and that a cluster only needs
to go through such an upgrade once in its lifecycle, we assessed that this
optimization would have low cost-effectiveness and decided not to pursue it.
### What problem does this PR solve?
Issue Number: close #xxx
Related PR: #xxx
Problem Summary:
### Release note
None
### Check List (For Author)
- Test <!-- At least one of them must be included. -->
- [ ] 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.
- [x] 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?
- [x] 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
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