protected virtual async Task <IEnumerable <TIn> > JoinBatch(JoinBatch <TIn> batch)
{
if (m_rowCache.Count == 0)
{
InitializeCache(m_rowCache);
}
if (batch.Strategy == CacheLookupStrategy.NoLookup)
{
return(batch.Data);
}
Func <TIn, object> accessor = m_typeAccessor.GetPropertyAccessor(this.m_joinOnMapping.DestColumnOffset);
var outputList = new List <TIn>(batch.Data.Length / 2);
var remoteLookupList = new List <TIn>(batch.Data.Length / 2);
int missCount = 0;
lock (m_rowCache) //may have race condition with dimtableinserter who will update the global cache
{
foreach (var input in batch.Data)
{
IDimRow <TLookupKey> row;
if (m_rowCache.TryGetValue((TLookupKey)accessor(input), out row))
{
this.OnSuccessfulLookup(input, row);
outputList.Add(input);
}
else
{
missCount++;
if (batch.Strategy == CacheLookupStrategy.RemoteLookup)
{
remoteLookupList.Add(input);
}
else
{
//Local lookup failed. record in garbage recorder as the input is discarded.
this.GarbageRecorder.Record(input);
}
}
}
}
foreach (var cacheMiss in remoteLookupList)
{
//post to dim inserter to do remote lookup (insert to tmp table and do a MERGE)
await m_dimInserter.SendAsync(cacheMiss).ConfigureAwait(false);
}
m_logger.DebugFormat("{0} {1} cache miss among {2} lookup in this round of JoinBatch()", FullName, missCount, batch.Data.Length);
return(outputList);
}
/// <summary>
/// Retrieves the property value of column index i using the delegates stored
/// </summary>
/// <param name="i">column index</param>
/// <returns></returns>
public dynamic GetValue(int i)
{
Func <T, dynamic> func = m_typeAccessor.GetPropertyAccessor(i);
/*var value = func(Current);
* var mapping = m_typeAccessor.GetColumnMapping(i);
*
* Console.WriteLine("default value: "+mapping.DefaultValue);
* Console.WriteLine("computed value: "+value);
* Console.WriteLine("are equal: " + object.ReferenceEquals(value, mapping.DefaultValue));
* Console.WriteLine("mapping: " + mapping.DestColumnName + ", " + mapping.DestColumnOffset);
* Console.ReadKey();*/
return(func(Current));
}
