private static List <ConfigurationAction> GetActionsForEventualConsistency(string ContainerName, ReplicaConfiguration config, SubSLA subSLA, ClientUsageData usage, string slaId)
{
List <ConfigurationAction> result = new List <ConfigurationAction>();
int desiredLatency = subSLA.Latency;
// we first compute the maximum probability of meeting the latency with current replicas.
float currentMaxProbability = usage.ServerRTTs
.Where(sr => config.PrimaryServers.Contains(sr.Key) || config.SecondaryServers.Contains(sr.Key))
.Max(sr => sr.Value.ProbabilityOfFindingValueLessThanGiven(desiredLatency));
// for any non-replica with higher probabiliy than both the currentMaxProbability and MIN_ACCEPTABLE_PROB_FOR_EVENTUAL_CONS, we create a new action.
IEnumerable <string> chosenServers = usage.ServerRTTs
.Where(sr => config.NonReplicaServers.Contains(sr.Key) &&
sr.Value.ProbabilityOfFindingValueLessThanGiven(desiredLatency) > currentMaxProbability &&
sr.Value.ProbabilityOfFindingValueLessThanGiven(desiredLatency) > ConstPool.MIN_ACCEPTABLE_PROB_FOR_CONS)
.Select(sr => sr.Key);
foreach (string server in chosenServers)
{
float utilityGain = (usage.ServerRTTs[server].ProbabilityOfFindingValueLessThanGiven(desiredLatency) - currentMaxProbability) * subSLA.Utility; /* * subSLA.NumberOfMisses*/
result.Add(new AddSecondaryServer(ContainerName, server, utilityGain, slaId, ConfigurationActionSource.NonConstraint, numberOfReads, numberOfWrites));
}
return(result);
}
private static List <ConfigurationAction> GetActionsFor_RMW_MON_CAUSAL_BOUNDED_Consistency(string ContainerName, ReplicaConfiguration config, SubSLA subSLA, ClientUsageData usage, string slaId)
{
List <ConfigurationAction> result = new List <ConfigurationAction>();
int desiredLatency = subSLA.Latency;
float currentMaxProbability = 0;
string nearestServer = null;
// Find the closest replica, i.e. the one that has the maximum probability of meeting the desired latency
foreach (string server in usage.ServerRTTs.Keys)
{
if (config.PrimaryServers.Contains(server) || config.SecondaryServers.Contains(server))
{
float prob = usage.ServerRTTs[server].ProbabilityOfFindingValueLessThanGiven(desiredLatency);
if (prob > currentMaxProbability)
{
currentMaxProbability = prob;
nearestServer = server;
}
}
}
// One action is to reduce the sync period for the nearest replica.
if (nearestServer != null && !config.PrimaryServers.Contains(nearestServer))
{
int oldInterval = config.GetSyncPeriod(nearestServer);
if ((oldInterval * ConstPool.ADJUSTING_SYNC_INTERVAL_MULTIPLIER) > ConstPool.MINIMUM_ALLOWED_SYNC_INTERVAL)
{
// TODO: This can't be right. The utility gain for adjusting the sync period is hard to predict.
float utilityGain = currentMaxProbability * subSLA.Utility; /* * subSLA.NumberOfMisses*/
result.Add(new AdjustSyncPeriod(ContainerName, nearestServer, utilityGain, slaId, ConfigurationActionSource.NonConstraint, numberOfReads, numberOfWrites));
}
}
// For any non-replica with higher probabiliy than both the currentMaxProbability and MIN_ACCEPTABLE_PROB_FOR_EVENTUAL_CONS, we create a new action.
IEnumerable <string> chosenServers = usage.ServerRTTs
.Where(sr => config.NonReplicaServers.Contains(sr.Key) &&
sr.Value.ProbabilityOfFindingValueLessThanGiven(desiredLatency) > currentMaxProbability &&
sr.Value.ProbabilityOfFindingValueLessThanGiven(desiredLatency) > ConstPool.MIN_ACCEPTABLE_PROB_FOR_CONS)
.Select(sr => sr.Key);
foreach (string server in chosenServers)
{
float utilityGain = (usage.ServerRTTs[server].ProbabilityOfFindingValueLessThanGiven(desiredLatency) - currentMaxProbability) * subSLA.Utility; /* * subSLA.NumberOfMisses*/
result.Add(new AddSecondaryServer(ContainerName, server, utilityGain, slaId, ConfigurationActionSource.NonConstraint, numberOfReads, numberOfWrites));
}
return(result);
}
private static List <ConfigurationAction> GetActionsForStrongConsistency(string ContainerName, ReplicaConfiguration config, SubSLA subSLA, ClientUsageData usage, string slaId)
{
List <ConfigurationAction> result = new List <ConfigurationAction>();
int desiredLatency = subSLA.Latency;
// we first compute the maximum probability of meeting the latency with primary servers.
float currentMaxProbability = usage.ServerRTTs
.Where(sr => config.PrimaryServers.Contains(sr.Key))
.Max(sr => sr.Value.ProbabilityOfFindingValueLessThanGiven(desiredLatency));
// for any secondary replica with higher probability than the primary, we create an action to make that secondary the solo primary.
// TODO: shouldn't this just pick one secondary with the max probability, i.e. why try to make multiple solo primaries?
IEnumerable <string> chosenSecondaries = usage.ServerRTTs
.Where(sr => config.SecondaryServers.Contains(sr.Key) &&
!config.ReadOnlySecondaryServers.Contains(sr.Key) &&
sr.Value.ProbabilityOfFindingValueLessThanGiven(desiredLatency) > currentMaxProbability)
.Select(sr => sr.Key);
foreach (string server in chosenSecondaries)
{
float utilityGain = (usage.ServerRTTs[server].ProbabilityOfFindingValueLessThanGiven(desiredLatency) - currentMaxProbability) * subSLA.Utility; /* * subSLA.NumberOfMisses*/
result.Add(new MakeSoloPrimaryServer(ContainerName, server, utilityGain, slaId, ConfigurationActionSource.NonConstraint, numberOfReads, numberOfWrites));
}
// for any server with higher probabiliy than the primary, we create an action to make that server one of the primaries.
IEnumerable <string> chosenServers = usage.ServerRTTs
.Where(sr => (config.SecondaryServers.Contains(sr.Key) || config.NonReplicaServers.Contains(sr.Key)) &&
!config.ReadOnlySecondaryServers.Contains(sr.Key) &&
sr.Value.ProbabilityOfFindingValueLessThanGiven(desiredLatency) > currentMaxProbability)
.Select(sr => sr.Key);
foreach (string server in chosenServers)
{
float utilityGain = (usage.ServerRTTs[server].ProbabilityOfFindingValueLessThanGiven(desiredLatency) - currentMaxProbability) * subSLA.Utility; /* * subSLA.NumberOfMisses*/
result.Add(new AddPrimaryServer(ContainerName, server, utilityGain, slaId, ConfigurationActionSource.NonConstraint, numberOfReads, numberOfWrites));
}
return(result);
}
