/// <summary>Pick up replica node set for deleting replica as over-replicated.</summary>
/// <remarks>
/// Pick up replica node set for deleting replica as over-replicated.
/// First set contains replica nodes on rack with more than one
/// replica while second set contains remaining replica nodes.
/// If first is not empty, divide first set into two subsets:
/// moreThanOne contains nodes on nodegroup with more than one replica
/// exactlyOne contains the remaining nodes in first set
/// then pickup priSet if not empty.
/// If first is empty, then pick second.
/// </remarks>
protected internal override ICollection <DatanodeStorageInfo> PickupReplicaSet(ICollection
<DatanodeStorageInfo> first, ICollection <DatanodeStorageInfo> second)
{
// If no replica within same rack, return directly.
if (first.IsEmpty())
{
return(second);
}
// Split data nodes in the first set into two sets,
// moreThanOne contains nodes on nodegroup with more than one replica
// exactlyOne contains the remaining nodes
IDictionary <string, IList <DatanodeStorageInfo> > nodeGroupMap = new Dictionary <string
, IList <DatanodeStorageInfo> >();
foreach (DatanodeStorageInfo storage in first)
{
string nodeGroupName = NetworkTopology.GetLastHalf(storage.GetDatanodeDescriptor(
).GetNetworkLocation());
IList <DatanodeStorageInfo> storageList = nodeGroupMap[nodeGroupName];
if (storageList == null)
{
storageList = new AList <DatanodeStorageInfo>();
nodeGroupMap[nodeGroupName] = storageList;
}
storageList.AddItem(storage);
}
IList <DatanodeStorageInfo> moreThanOne = new AList <DatanodeStorageInfo>();
IList <DatanodeStorageInfo> exactlyOne = new AList <DatanodeStorageInfo>();
// split nodes into two sets
foreach (IList <DatanodeStorageInfo> datanodeList in nodeGroupMap.Values)
{
if (datanodeList.Count == 1)
{
// exactlyOne contains nodes on nodegroup with exactly one replica
exactlyOne.AddItem(datanodeList[0]);
}
else
{
// moreThanOne contains nodes on nodegroup with more than one replica
Sharpen.Collections.AddAll(moreThanOne, datanodeList);
}
}
return(moreThanOne.IsEmpty() ? exactlyOne : moreThanOne);
}
/// <summary>Scan the targets list: all targets should be on different NodeGroups.</summary>
/// <remarks>
/// Scan the targets list: all targets should be on different NodeGroups.
/// Return false if two targets are found on the same NodeGroup.
/// </remarks>
private static bool CheckTargetsOnDifferentNodeGroup(DatanodeStorageInfo[] targets
)
{
if (targets.Length == 0)
{
return(true);
}
ICollection <string> targetSet = new HashSet <string>();
foreach (DatanodeStorageInfo storage in targets)
{
DatanodeDescriptor node = storage.GetDatanodeDescriptor();
string nodeGroup = NetworkTopology.GetLastHalf(node.GetNetworkLocation());
if (targetSet.Contains(nodeGroup))
{
return(false);
}
else
{
targetSet.AddItem(nodeGroup);
}
}
return(true);
}
