/** Invariant is that all servers have between acceptable range number of regions. */
public boolean assertClusterOverallAsBalanced(List<ServerAndLoad> servers, int tablenum) {
int numServers = servers.size();
int numRegions = 0;
int maxRegions = 0;
int minRegions = Integer.MAX_VALUE;
for (ServerAndLoad server : servers) {
int nr = server.getLoad();
if (nr > maxRegions) {
maxRegions = nr;
}
if (nr < minRegions) {
minRegions = nr;
}
numRegions += nr;
}
if (maxRegions - minRegions < 2) {
// less than 2 between max and min, can't balance
return true;
}
int min = numRegions / numServers;
int max = numRegions % numServers == 0 ? min : min + 1;
for (ServerAndLoad server : servers) {
if (server.getLoad() < 0
|| server.getLoad() > max + tablenum / 2 + 1
|| server.getLoad() < min - tablenum / 2 - 1) return false;
}
return true;
}
/** Invariant is that all servers have between floor(avg) and ceiling(avg) number of regions. */
public void assertClusterAsBalanced(List<ServerAndLoad> servers) {
int numServers = servers.size();
int numRegions = 0;
int maxRegions = 0;
int minRegions = Integer.MAX_VALUE;
for (ServerAndLoad server : servers) {
int nr = server.getLoad();
if (nr > maxRegions) {
maxRegions = nr;
}
if (nr < minRegions) {
minRegions = nr;
}
numRegions += nr;
}
if (maxRegions - minRegions < 2) {
// less than 2 between max and min, can't balance
return;
}
int min = numRegions / numServers;
int max = numRegions % numServers == 0 ? min : min + 1;
for (ServerAndLoad server : servers) {
assertTrue(server.getLoad() >= 0);
assertTrue(server.getLoad() <= max);
assertTrue(server.getLoad() >= min);
}
}
protected void updateLoad(
final Map<ServerName, ServerAndLoad> map, final ServerName sn, final int diff) {
ServerAndLoad sal = map.get(sn);
if (sal == null) sal = new ServerAndLoad(sn, 0);
sal = new ServerAndLoad(sn, sal.getLoad() + diff);
map.put(sn, sal);
}
protected String printStats(List<ServerAndLoad> servers) {
int numServers = servers.size();
int totalRegions = 0;
for (ServerAndLoad server : servers) {
totalRegions += server.getLoad();
}
float average = (float) totalRegions / numServers;
int max = (int) Math.ceil(average);
int min = (int) Math.floor(average);
return "[srvr="
+ numServers
+ " rgns="
+ totalRegions
+ " avg="
+ average
+ " max="
+ max
+ " min="
+ min
+ "]";
}