/// <summary>
/// 只能添加一次。
/// </summary>
/// <param name="key"></param>
/// <param name="r"></param>
internal void AddRecordAccessed(Record.RootInfo root, RecordAccessed r)
{
if (IsCompleted)
{
throw new Exception("Transaction Is Completed");
}
r.InitRootInfo(root, null);
accessedRecords.Add(root.TableKey, r);
}
private CheckResult _check_(bool writeLock, RecordAccessed e)
{
if (writeLock)
{
switch (e.OriginRecord.State)
{
case GlobalCacheManager.StateRemoved:
// fall down
case GlobalCacheManager.StateInvalid:
return(CheckResult.RedoAndReleaseLock); // 写锁发现Invalid，肯定有Reduce请求。
case GlobalCacheManager.StateModify:
return(e.Timestamp != e.OriginRecord.Timestamp ? CheckResult.Redo : CheckResult.Success);
case GlobalCacheManager.StateShare:
// 这里可能死锁：另一个先获得提升的请求要求本机Recude，但是本机Checkpoint无法进行下去，被当前事务挡住了。
// 通过 GlobalCacheManager 检查死锁，返回失败;需要重做并释放锁。
if (e.OriginRecord.Acquire(GlobalCacheManager.StateModify) != GlobalCacheManager.StateModify)
{
logger.Warn("Acquire Faild. Maybe DeadLock Found {0}", e.OriginRecord);
e.OriginRecord.State = GlobalCacheManager.StateInvalid;
return(CheckResult.RedoAndReleaseLock);
}
e.OriginRecord.State = GlobalCacheManager.StateModify;
return(e.Timestamp != e.OriginRecord.Timestamp ? CheckResult.Redo : CheckResult.Success);
}
return(e.Timestamp != e.OriginRecord.Timestamp ? CheckResult.Redo : CheckResult.Success); // imposible
}
else
{
if (e.OriginRecord.State == GlobalCacheManager.StateInvalid ||
e.OriginRecord.State == GlobalCacheManager.StateRemoved)
{
return(CheckResult.RedoAndReleaseLock); // 发现Invalid，肯定有Reduce请求或者被Cache清理，此时保险起见释放锁。
}
return(e.Timestamp != e.OriginRecord.Timestamp ? CheckResult.Redo : CheckResult.Success);
}
}
