feat: Add session closed metric

[KirillKurdyukov]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 90.62500% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.19%. Comparing base (ae5b7db) to head (293068d).
⚠️ Report is 10 commits behind head on master.

Files with missing lines	Patch %	Lines
...ain/java/tech/ydb/table/impl/pool/SessionPool.java	75.00%	1 Missing and 3 partials ⚠️
...src/main/java/tech/ydb/query/impl/SessionPool.java	96.00%	0 Missing and 1 partial ⚠️
...in/java/tech/ydb/table/impl/pool/WaitingQueue.java	93.33%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #700      +/-   ##
============================================
+ Coverage     71.88%   72.19%   +0.31%     
- Complexity     3475     3496      +21     
============================================
  Files           390      391       +1     
  Lines         16206    16309     +103     
  Branches       1698     1706       +8     
============================================
+ Hits          11649    11774     +125     
+ Misses         3906     3884      -22     
  Partials        651      651              

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[robot-vibe-db]

AI Review Summary

Verdict: ❌ 0 critical issues, 1 major issue found

Critical issues

No critical issues found.

Other findings

• Major | Medium: Table pool sessions retired due to INTERNAL_ERROR never emit the new closed metric — the condition block in updateSessionState doesn't match INTERNAL_ERROR, so closeSession() is never called despite the session transitioning to BROKEN — table/…/StatefulSession.java:41-50
• Minor | Medium: The "reason" attribute key in onSessionClosed() is unprefixed, unlike all other attribute keys in PoolMetrics which use the prefix (e.g. ydb.query.session.status_code) — table/…/PoolMetrics.java:83
• Minor | Medium: Behavioural change — query pool no longer retires sessions on INTERNAL_ERROR (old code did). This diverges from the table pool, which still retires on INTERNAL_ERROR. Explicitly tested, but the inconsistency between pools could surprise users — query/…/SessionPool.java:181-208
• Minor | Low: Early return on !isStarted in query pool updateSessionState still updates lastActive timestamp; harmless but asymmetric — query/…/SessionPool.java:182-183

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This review was generated automatically. Critical issues require attention; other findings are advisory.
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[robot-vibe-db]

Full analysis log

Analysis performed by claude, claude-opus-4-6.