public static void HandleTailPinned(object arg, TailPinnedEventArgs tailPinnedEventArgs)
{
Console.WriteLine("TailPinned has fired");
// Based on the implementation of a logging application, the log base can be moved
// to free up more log space and if it is not possible to move the
// base, the application should report by throwing an exception.
if (MyLog.AdvanceBase)
{
try
{
// TailPnnedEventArgs has the recommended sequence number and its generated
// based on PinnedTailThreshold policy.
// This does not map to an actual sequence number in the record sequence
// but an approximation and potentially frees up the threshold % log space
// when the log base is advanced to a valid sequence number closer to the
// recommended sequence number.
// The user should use this sequence number to locate a closest valid sequence
// number to advance the base of the log.
SequenceNumber recommendedTargetSeqNum = tailPinnedEventArgs.TargetSequenceNumber;
// Get the actual Target sequence number.
SequenceNumber actualTargetSeqNum = MyLog.GetAdvanceBaseSeqNumber(recommendedTargetSeqNum);
MySequence.AdvanceBaseSequenceNumber(actualTargetSeqNum);
}
catch (Exception e)
{
Console.WriteLine("Exception thrown {0} {1}", e.GetType(), e.Message);
}
}
else
{
// Report back Error if under some conditions the log cannot
// advance the base sequence number.
Console.WriteLine("Reporting Error! Unable to move the base sequence number!");
throw new IOException();
}
}
private void TailPinned(object sender, TailPinnedEventArgs e)
{
Debug.WriteLine($"Log {this.logFileBase}: tail pinned! Suggested that we advance base to {e.TargetSequenceNumber.Identifier()}");
}
