Bug 9117: allocator performance improvements

Fix for following optimization:
Make PodAllocator aware of host tags.

If the service offering has host_tag specified, PodAllocator can pick the pods having hosts with that tag. This would reduce the list of pods the allocator
has to iterate through to find a suitable pod.

Added a new PodAllocator 'HostTagBasedPodAllocator' that extends the 'UserConcentratedAllocator'.

core/src/com/cloud/dc/dao/HostPodDao.java

@@ -30,6 +30,8 @@ public interface HostPodDao extends GenericDao<HostPodVO, Long> {
 	
 	public HostPodVO findByName(String name, long dcId);
 	
-	public HashMap<Long, List<Object>> getCurrentPodCidrSubnets(long zoneId, long podIdToSkip);
+	public HashMap<Long, List<Object>> getCurrentPodCidrSubnets(long zoneId, long podIdToSkip);
+	
+	public List<HostPodVO> listPodsByHostTag(long dcId, String hostTag);
 
 }

core/src/com/cloud/dc/dao/HostPodDaoImpl.java

@@ -36,6 +36,7 @@ import com.cloud.utils.db.GenericDaoBase;
 import com.cloud.utils.db.SearchBuilder;
 import com.cloud.utils.db.SearchCriteria;
 import com.cloud.utils.db.Transaction;
+import com.cloud.utils.exception.CloudRuntimeException;
 import com.cloud.utils.net.NetUtils;
 
 @Local(value={HostPodDao.class})
@@ -43,7 +44,11 @@ public class HostPodDaoImpl extends GenericDaoBase<HostPodVO, Long> implements H
     private static final Logger s_logger = Logger.getLogger(HostPodDaoImpl.class);
 	
 	protected SearchBuilder<HostPodVO> DataCenterAndNameSearch;
-	protected SearchBuilder<HostPodVO> DataCenterIdSearch;
+	protected SearchBuilder<HostPodVO> DataCenterIdSearch;
+	
+	private static final String PodsByHostTag = "SELECT DISTINCT host_pod_ref.* FROM (host_tags JOIN host ON host_tags.host_id = host.id AND host_tags.tag = ?) JOIN host_pod_ref " +
+			"ON host_pod_ref.id = host.pod_id WHERE host_pod_ref.data_center_id = ? ";
+
 	
 	protected HostPodDaoImpl() {
 	    DataCenterAndNameSearch = createSearchBuilder();
@@ -96,7 +101,31 @@ public class HostPodDaoImpl extends GenericDaoBase<HostPodVO, Long> implements H
         }
         
         return currentPodCidrSubnets;
-	}
+	}
+	
+	@Override
+	public List<HostPodVO> listPodsByHostTag(long dcId, String hostTag) {
+		
+		StringBuilder sql = new StringBuilder(PodsByHostTag);
+    
+	    Transaction txn = Transaction.currentTxn();
+	    PreparedStatement pstmt = s_initStmt;
+	    try {
+	        pstmt = txn.prepareAutoCloseStatement(sql.toString());
+	        int i = 1;
+	        pstmt.setString(i++, hostTag);
+	        pstmt.setLong(i++, dcId);
+	        ResultSet rs = pstmt.executeQuery();
+	        List<HostPodVO> pods = new ArrayList<HostPodVO>();
+	        while (rs.next()) {
+	        	pods.add(toEntityBean(rs, false));
+	        }
+	        return pods;
+	    } catch (SQLException e) {
+	        throw new CloudRuntimeException("Unable to execute " + pstmt.toString(), e);
+	    }
+
+	}	
 	
 	@Override
 	public boolean configure(String name, Map<String, Object> params) throws ConfigurationException {

server/src/com/cloud/agent/manager/allocator/impl/HostTagBasedPodAllocator.java

@@ -0,0 +1,65 @@
+/**
+ *  Copyright (C) 2010 Cloud.com, Inc.  All rights reserved.
+ * 
+ * This software is licensed under the GNU General Public License v3 or later.
+ * 
+ * It is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or any later version.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * 
+ */
+package com.cloud.agent.manager.allocator.impl;
+
+import java.util.ArrayList;
+import java.util.List;
+import javax.ejb.Local;
+import org.apache.log4j.Logger;
+import com.cloud.agent.manager.allocator.PodAllocator;
+import com.cloud.dc.HostPodVO;
+import com.cloud.dc.dao.HostPodDao;
+import com.cloud.service.ServiceOffering;
+import com.cloud.utils.component.Inject;
+
+/*
+ * Use this PodAllocator when the deployment is such that pod has homogeneous tags on hosts.
+ * If any pod can contain hosts with any tag, this optimization will not yield much benefit.  
+ */
+@Local(value=PodAllocator.class)
+public class HostTagBasedPodAllocator extends UserConcentratedAllocator {
+    private final static Logger s_logger = Logger.getLogger(HostTagBasedPodAllocator.class);
+    @Inject HostPodDao _podDao;
+    
+    public HostTagBasedPodAllocator() {
+    }
+ 
+    @Override
+    protected List<HostPodVO> listPods(long zoneId, ServiceOffering offering){
+    	List<HostPodVO> podsInZone = new ArrayList<HostPodVO>();
+    	
+    	if(offering != null && offering.getHostTag() != null){
+    		String hostTag = offering.getHostTag();
+    		podsInZone = _podDao.listPodsByHostTag(zoneId, hostTag);
+    		
+    		if(podsInZone.size() == 0){
+    	    	if (s_logger.isInfoEnabled()) {
+    	    		s_logger.info("No Pods found in Zone: '"+zoneId+"' having Hosts with host tag: '"+ hostTag +"'");
+    	    	}
+    		}else{
+    	    	if (s_logger.isDebugEnabled()) {
+    	    		s_logger.debug("Found "+podsInZone.size() +" Pods in Zone: '"+zoneId+"' having Hosts with host tag: '"+ hostTag +"'");
+    	    	}
+    		}
+    	}else{
+    		podsInZone = super.listPods(zoneId, offering);
+    	}
+    	
+    	return podsInZone;
+    }
+}

server/src/com/cloud/agent/manager/allocator/impl/UserConcentratedAllocator.java

@@ -83,7 +83,7 @@ public class UserConcentratedAllocator implements PodAllocator {
     @Override
     public Pair<HostPodVO, Long> allocateTo(VirtualMachineTemplate template, ServiceOfferingVO offering, DataCenterVO zone, long accountId, Set<Long> avoids) {
     	long zoneId = zone.getId();
-        List<HostPodVO> podsInZone = _podDao.listByDataCenterId(zoneId);
+        List<HostPodVO> podsInZone = listPods(zoneId, offering);
         
         if (podsInZone.size() == 0) {
             s_logger.debug("No pods found in zone " + zone.getName());
@@ -100,10 +100,7 @@ public class UserConcentratedAllocator implements PodAllocator {
 					s_logger.debug("Checking Pod: " + podId);
 				}
 				
-        		if (template != null && !templateAvailableInPod(template.getId(), pod.getDataCenterId(), podId)) {
-        			continue;
-        		}
-        		
+       		
         		if (offering != null) {
         			// test for enough memory in the pod (make sure to check for enough memory for the service offering, plus some extra padding for xen overhead
         			long[] hostCandiates = new long[1];
@@ -160,6 +157,14 @@ public class UserConcentratedAllocator implements PodAllocator {
         	return new Pair<HostPodVO, Long>(selectedPod, podHostCandidates.get(selectedPod.getId()));
         }
     }
+    
+    protected List<HostPodVO> listPods(long zoneId, ServiceOffering offering){
+    	List<HostPodVO> podsInZone = _podDao.listByDataCenterId(zoneId);
+    	if (s_logger.isDebugEnabled()) {
+    		s_logger.debug("Found "+podsInZone.size() +" Pods in Zone: "+zoneId);
+    	}
+    	return podsInZone;
+    }
 
     private boolean dataCenterAndPodHasEnoughCapacity(long dataCenterId, long podId, long capacityNeeded, short capacityType, long[] hostCandidate) {
         List<CapacityVO> capacities = null;