/**
* Compute the average load across all region servers. Currently, this uses a very naive
* computation - just uses the number of regions being served, ignoring stats about number of
* requests.
*
* @return the average load
*/
protected synchronized double getAverageLoad() {
int numServers = 0, totalLoad = 0;
for (Map.Entry<ServerName, Set<HRegionInfo>> e : serverHoldings.entrySet()) {
Set<HRegionInfo> regions = e.getValue();
ServerName serverName = e.getKey();
int regionCount = regions.size();
if (serverManager.isServerOnline(serverName)) {
totalLoad += regionCount;
numServers++;
}
}
if (numServers > 1) {
// The master region server holds only a couple regions.
// Don't consider this server in calculating the average load
// if there are other region servers to avoid possible confusion.
Set<HRegionInfo> hris = serverHoldings.get(server.getServerName());
if (hris != null) {
totalLoad -= hris.size();
numServers--;
}
}
return numServers == 0 ? 0.0 : (double) totalLoad / (double) numServers;
}
