[fix][broker] Fence reset cursor by timestamp to avoid concurrent timestamp-based position lookups

[codelipenghui]

Motivation

The resetCursor(long timestamp) method was not protected by the subscription fencing mechanism (IS_FENCED_UPDATER), allowing concurrent reset operations to interfere with one another. This may result in performance degradation during timestamp-based position lookups, particularly when tiered storage is enabled.

Modifications

Apply the same fencing mechanism used by resetCursor(Position) to resetCursor(long timestamp) by sharing the internal resetCursorInternal() method.

Verifying this change

• Added unit test testConcurrentResetCursorByTimestamp in SubscriptionSeekTest.java
• Run: mvn -pl pulsar-broker -Dtest=SubscriptionSeekTest#testConcurrentResetCursorByTimestamp test

Documentation

• doc-not-needed

[lhotari]

LGTM

[codecov-commenter]

Codecov Report

❌ Patch coverage is 69.23077% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.66%. Comparing base (99fdca8) to head (70b15f4).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
...ker/service/persistent/PersistentSubscription.java	69.23%	4 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             master   #25151       +/-   ##
=============================================
+ Coverage     37.41%   72.66%   +35.25%     
- Complexity    13148    33884    +20736     
=============================================
  Files          1899     1956       +57     
  Lines        150564   154736     +4172     
  Branches      17156    17643      +487     
=============================================
+ Hits          56334   112440    +56106     
+ Misses        86500    33345    -53155     
- Partials       7730     8951     +1221     

Flag	Coverage Δ
inttests	25.78% <15.38%> (+0.13%)	⬆️
systests	22.51% <15.38%> (+0.05%)	⬆️
unittests	73.61% <69.23%> (+39.57%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...ker/service/persistent/PersistentSubscription.java	75.78% <69.23%> (+29.10%)	⬆️

... and 1424 files with indirect coverage changes

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