Address review feedback on the weighted allocation algorithm

vm_instance.update_time is a TIMESTAMP column, so there is no date that
reliably means "never" - anything past 2038 is out of range. Counting
with no cut-off used Long.MAX_VALUE, which is roughly year 292 million.
The query now leaves the timestamp out entirely in that case rather than
binding an impossible one.

Also catch Exception rather than Throwable in the new query, and put the
config key array one entry per line.

Signed-off-by: Brad House <bhouse@nexthop.ai>

Author: bhouse-nexthop

engine/schema/src/main/java/com/cloud/vm/dao/VMInstanceDaoImpl.java

@@ -155,7 +155,10 @@ public class VMInstanceDaoImpl extends GenericDaoBase<VMInstanceVO, Long> implem
     private static final String COUNT_VMS_BASED_ON_VGPU_TYPES2 =
             "GROUP BY gpu_card.name, vgpu_profile.name";
 
-    private static final String COUNT_VMS_BY_HOST = "SELECT host.id, COUNT(vm.id), SUM(IF(vm.update_time > ?, 1, 0)) " +
+    // %s is the "changed state recently" test, or a constant 0 when no cut-off is given. It is not
+    // a bound parameter because there is no timestamp that reliably means "never" - update_time is
+    // a TIMESTAMP column, so anything past 2038 is out of range.
+    private static final String COUNT_VMS_BY_HOST = "SELECT host.id, COUNT(vm.id), SUM(IF(%s, 1, 0)) " +
             "FROM `cloud`.`host` host LEFT JOIN `cloud`.`vm_instance` vm " +
             "ON vm.host_id = host.id AND vm.state IN ('Running', 'Starting', 'Stopping', 'Migrating') " +
             "AND vm.removed IS NULL WHERE host.type = 'Routing' AND host.removed IS NULL AND host.data_center_id = ? ";
@@ -807,7 +810,7 @@ public Pair<List<Long>, Map<Long, Double>> listPodIdsInZoneByVmCount(long dataCe
     public Map<Long, Pair<Long, Long>> countVmsByHost(long dcId, Long podId, Long clusterId, Date changedStateAfter) {
         TransactionLegacy txn = TransactionLegacy.currentTxn();
         Map<Long, Pair<Long, Long>> result = new HashMap<>();
-        String sql = COUNT_VMS_BY_HOST;
+        String sql = String.format(COUNT_VMS_BY_HOST, changedStateAfter != null ? "vm.update_time > ?" : "0");
         if (podId != null) {
             sql = sql + " AND host.pod_id = ? ";
         }
@@ -818,9 +821,9 @@ public Map<Long, Pair<Long, Long>> countVmsByHost(long dcId, Long podId, Long cl
         try {
             PreparedStatement pstmt = txn.prepareAutoCloseStatement(sql);
             int index = 1;
-            // a cut-off in the future counts nothing as recent, which is what a null asks for
-            long cutOff = changedStateAfter != null ? changedStateAfter.getTime() : Long.MAX_VALUE;
-            pstmt.setTimestamp(index++, new Timestamp(cutOff));
+            if (changedStateAfter != null) {
+                pstmt.setTimestamp(index++, new Timestamp(changedStateAfter.getTime()));
+            }
             pstmt.setLong(index++, dcId);
             if (podId != null) {
                 pstmt.setLong(index++, podId);
@@ -835,7 +838,7 @@ public Map<Long, Pair<Long, Long>> countVmsByHost(long dcId, Long podId, Long cl
             return result;
         } catch (SQLException e) {
             throw new CloudRuntimeException("DB Exception on: " + sql, e);
-        } catch (Throwable e) {
+        } catch (Exception e) {
             throw new CloudRuntimeException("Caught: " + sql, e);
         }
     }

server/src/main/java/com/cloud/agent/manager/allocator/impl/WeightedHostScorer.java

@@ -400,8 +400,19 @@ public String getConfigComponentName() {
 
     @Override
     public ConfigKey<?>[] getConfigKeys() {
-        return new ConfigKey<?>[] {HostScoringWeights.CpuAllocatedWeight, HostScoringWeights.CpuUsedWeight, HostScoringWeights.MemoryAllocatedWeight, HostScoringWeights.MemoryUsedWeight,
-                VmCountWeight, RecentStartWeight, DominantResourceWeight, RecentStartWindow, ExpectedVmsPerHost,
-                CpuUtilisationThreshold, MemoryUtilisationThreshold, SelectionSpread};
+        return new ConfigKey<?>[] {
+                HostScoringWeights.CpuAllocatedWeight,
+                HostScoringWeights.CpuUsedWeight,
+                HostScoringWeights.MemoryAllocatedWeight,
+                HostScoringWeights.MemoryUsedWeight,
+                VmCountWeight,
+                RecentStartWeight,
+                DominantResourceWeight,
+                RecentStartWindow,
+                ExpectedVmsPerHost,
+                CpuUtilisationThreshold,
+                MemoryUtilisationThreshold,
+                SelectionSpread
+        };
     }
 }