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Use Stopwatch for LockableContext acquire timeouts #1772

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Merged
kevin-montrose merged 3 commits into from
May 18, 2026
+7 −5
Merged

Use Stopwatch for LockableContext acquire timeouts #1772

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76210c9
fix: use Stopwatch for LockableContext acquire timeouts
unsafePtr May 5, 2026
b575dda
fix: treat negative timeout as infinite in LockableContext acquire loops
unsafePtr May 11, 2026
a344e56
Merge remote-tracking branch 'upstream/main' into fix/lockablecontext…
unsafePtr May 18, 2026
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12 changes: 7 additions & 5 deletions libs/storage/Tsavorite/cs/src/core/ClientSession/TransactionalContext.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -114,7 +114,7 @@ internal static bool DoTransactionalTryLock<TSessionFunctionsWrapper, TTransacti
// We can't start each retry with a full timeout because we might always fail if someone is not unlocking (e.g. another thread hangs
// somehow while holding a lock, or the current thread has issued two lock calls on two key sets and the second tries to lock one in
// the first, and so on). So set the timeout high enough to accommodate as many retries as you want.
var startTime = DateTime.UtcNow;
var startTimestamp = Stopwatch.GetTimestamp();

Retry:
var prevBucketIndex = -1L;
Expand All @@ -141,7 +141,8 @@ internal static bool DoTransactionalTryLock<TSessionFunctionsWrapper, TTransacti
DoTransactionalUnlock(clientSession, keys[..keyIdx]);

// Lock failure is the only place we check the timeout. If we've exceeded that, or if we've had a cancellation, return false.
if (cancellationToken.IsCancellationRequested || DateTime.UtcNow.Ticks - startTime.Ticks > timeout.Ticks)
// A negative timeout (e.g. Timeout.InfiniteTimeSpan) means wait indefinitely until cancellation.
if (cancellationToken.IsCancellationRequested || (timeout >= TimeSpan.Zero && Stopwatch.GetElapsedTime(startTimestamp) > timeout))
return false;

// No cancellation and we're within the timeout. We've released our locks so this refresh will let other threads advance
Expand All @@ -161,7 +162,7 @@ internal static bool DoManualTryPromoteLock<TSessionFunctionsWrapper, TTransacti
where TSessionFunctionsWrapper : ISessionFunctionsWrapper<TInput, TOutput, TContext, TStoreFunctions, TAllocator>
where TTransactionalKey : ITransactionalKey
{
var startTime = DateTime.UtcNow;
var startTimestamp = Stopwatch.GetTimestamp();
while (true)
{
if (clientSession.store.InternalPromoteLock(key.KeyHash))
Expand All @@ -173,8 +174,9 @@ internal static bool DoManualTryPromoteLock<TSessionFunctionsWrapper, TTransacti
return true;
}

// CancellationToken can accompany either of the other two mechanisms
if (cancellationToken.IsCancellationRequested || DateTime.UtcNow.Ticks - startTime.Ticks > timeout.Ticks)
// CancellationToken can accompany either of the other two mechanisms.
// A negative timeout (e.g. Timeout.InfiniteTimeSpan) means wait indefinitely until cancellation.
if (cancellationToken.IsCancellationRequested || (timeout >= TimeSpan.Zero && Stopwatch.GetElapsedTime(startTimestamp) > timeout))
break; // out of the retry loop

// Lock failed, must retry
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