/// <summary>
/// Creates jobs for the parallel group by.
/// Note that the last job in the array has the end set to the end of the result table.
/// Each job will receive a range from result table, hasher, comparer (cache on) and aggregates.
/// Note that they are all copies, because they contain a private state (hasher contains reference to the equality comparers to enable caching when computing the hash).
/// The comparers and hashers build in the constructor of this class are given to the last job, just like the aggregates passed to the construtor.
/// </summary>
private GroupByJob[] CreateJobs(ITableResults resTable, Aggregate[] aggs, ExpressionComparer[] comparers, ExpressionHasher[] hashers)
{
GroupByJob[] jobs = new GroupByJob[this.ThreadCount];
int current = 0;
int addition = resTable.NumberOfMatchedElements / this.ThreadCount;
if (addition == 0)
{
throw new ArgumentException($"{this.GetType()}, a range for a thread cannot be 0.");
}
// Set their internal cache.
var lastComp = RowEqualityComparerGroupKey.Factory(resTable, comparers, true);
var lastHasher = new RowHasher(hashers);
lastHasher.SetCache(lastComp.comparers);
for (int i = 0; i < jobs.Length - 1; i++)
{
var tmpComp = lastComp.Clone(cacheResults: true);
var tmpHash = lastHasher.Clone();
tmpHash.SetCache(tmpComp.comparers);
jobs[i] = CreateJob(tmpHash, tmpComp, aggs, resTable, current, current + addition);
current += addition;
}
jobs[jobs.Length - 1] = CreateJob(lastHasher, lastComp, aggs, resTable, current, resTable.NumberOfMatchedElements);
return(jobs);
}
/// <summary>
/// Creates jobs for the parallel group by.
/// Note that the last job in the array has the end set to the end of the result table.
/// Each job will receive a range from result table, hasher, comparer and aggregates.
/// Note that they are all copies, because they contain a private stete (hasher contains reference to the equality comparers to enable caching when computing the hash, aggregates
/// contain references to storage arrays to avoid casting in a tight loop).
/// The comparers and hashers build in the constructor of this class are given to the last job, just like the aggregates passed to the construtor.
/// The global Dictionary recieves a comparer that has no internal comparers set to some hasher.
/// </summary>
private GroupByJob[] CreateJobs(ITableResults resTable, Aggregate[] aggs, ExpressionComparer[] comparers, ExpressionHasher[] hashers)
{
GroupByJob[] jobs = new GroupByJob[this.ThreadCount];
int current = 0;
int addition = resTable.NumberOfMatchedElements / this.ThreadCount;
if (addition == 0)
{
throw new ArgumentException($"{this.GetType()}, a range for a thread cannot be 0.");
}
var lastComp = RowEqualityComparerGroupKey.Factory(resTable, comparers, true);
var lastHasher = new RowHasher(hashers);
lastHasher.SetCache(lastComp.comparers);
// It needs only comparator that has no comparers set as a cache to some hasher.
var globalGroups = new ConcurrentDictionary <GroupDictKey, AggregateBucketResult[]>(lastComp.Clone(cacheResults: false));
for (int i = 0; i < jobs.Length - 1; i++)
{
var tmpComp = lastComp.Clone(cacheResults: true);
var tmpHash = lastHasher.Clone();
tmpHash.SetCache(tmpComp.comparers);
jobs[i] = CreateJob(tmpHash, tmpComp, aggs, resTable, current, current + addition, globalGroups);
current += addition;
}
jobs[jobs.Length - 1] = CreateJob(lastHasher, lastComp, aggs, resTable, current, resTable.NumberOfMatchedElements, globalGroups);
return(jobs);
}
public static RowEqualityComparerInt Factory(ITableResults resTable, ExpressionComparer[] comparers, RowHasher hasher, bool cacheResults)
{
var newComparers = comparers.CloneHard(cacheResults);
var newHasher = hasher.Clone();
if (cacheResults)
{
newHasher.SetCache(newComparers);
}
else
{
newHasher.UnsetCache();
}
return(new RowEqualityComparerInt(resTable, newComparers, newHasher, cacheResults));
}
/// <summary>
/// Clones comparer and hasher. The cache is always set to true even for the hasher.
/// </summary>
protected static void CloneHasherAndComparer(RowEqualityComparerGroupKey comparer, RowHasher hasher, out RowEqualityComparerGroupKey retComparer, out RowHasher retHasher)
{
retComparer = comparer.Clone(cacheResults: true);
retHasher = hasher.Clone();
retHasher.SetCache(retComparer.comparers);
}
