Merge #108797

108797: concurrency: only count active waiter in totalAndMaxWaitDuration metric calculation r=arulajmani a=lyang24 concurrency: only count active waiter in totalAndMaxWaitDuration metric calculation. The lock wait duration should only apply for the waiters that are actively waiting. This change has no effect on wating readers since all waiting readers are active. We are excluding all inactive locking requests' wait time contribution to the total and max waiting duration. Fixes: #108683 Release note: None. Co-authored-by: Eric.Yang <[email protected]>
cockroachdb · Sep 5, 2023 · 407f33e · 407f33e
2 parents 3a12304 + de79e45
commit 407f33e
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Showing 2 changed files with 176 additions and 54 deletions.
diff --git a/pkg/kv/kvserver/concurrency/lock_table.go b/pkg/kv/kvserver/concurrency/lock_table.go
@@ -2152,7 +2152,7 @@ func (kl *keyLocks) lockHeldDuration(now time.Time) time.Duration {
 	return now.Sub(minStartTS)
 }
 
-// Returns the total amount of time all waiters in the queues of
+// Returns the total amount of time all active waiters in the queues of
 // readers and locking requests have been waiting on the key referenced in the
 // receiver.
 //
@@ -2172,14 +2172,16 @@ func (kl *keyLocks) totalAndMaxWaitDuration(now time.Time) (time.Duration, time.
 	}
 	for e := kl.queuedLockingRequests.Front(); e != nil; e = e.Next() {
 		qg := e.Value
-		g := qg.guard
-		g.mu.Lock()
-		waitDuration := now.Sub(g.mu.curLockWaitStart)
-		totalWaitDuration += waitDuration
-		if waitDuration > maxWaitDuration {
-			maxWaitDuration = waitDuration
+		if qg.active {
+			g := qg.guard
+			g.mu.Lock()
+			waitDuration := now.Sub(g.mu.curLockWaitStart)
+			totalWaitDuration += waitDuration
+			if waitDuration > maxWaitDuration {
+				maxWaitDuration = waitDuration
+			}
+			g.mu.Unlock()
 		}
-		g.mu.Unlock()
 	}
 	return totalWaitDuration, maxWaitDuration
 }