See also #32165
There were some frequent scan in metacache:
- List all segments whose start positions not synced
- List compacted segments
Those scan shall cause lots of CPU time when flushed segment number is
large meanwhile `Flushed` segments can be skipped in those two scenarios
This PR make:
- Add segment state shortcut in metacache
- List start positions state before `Flushed`
- Make compacted segments state to be `Dropped` and use `Dropped` state
while scanning them
---------
Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>
See also #27675
Since serialization segment buffer does not related to sync manager can
shall be done before submit into sync manager. So that the pk statistic
file could be more accurate and reduce complex logic inside sync
manager.
---------
Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>
