Ejemplo n.º 1
0
 /**
  * Add a value to this aggregate.
  *
  * @param database the database
  * @param distinct if the calculation should be distinct
  * @param v the value
  */
 void add(Database database, boolean distinct, Value v) {
   if (aggregateType == Aggregate.SELECTIVITY) {
     count++;
     if (distinctHashes == null) {
       distinctHashes = new IntIntHashMap();
     }
     int size = distinctHashes.size();
     if (size > Constants.SELECTIVITY_DISTINCT_COUNT) {
       distinctHashes = new IntIntHashMap();
       m2 += size;
     }
     int hash = v.hashCode();
     // the value -1 is not supported
     distinctHashes.put(hash, 1);
     return;
   } else if (aggregateType == Aggregate.COUNT_ALL) {
     count++;
     return;
   } else if (aggregateType == Aggregate.HISTOGRAM) {
     if (distinctValues == null) {
       distinctValues = ValueHashMap.newInstance();
     }
     AggregateData a = distinctValues.get(v);
     if (a == null) {
       if (distinctValues.size() < Constants.SELECTIVITY_DISTINCT_COUNT) {
         a = new AggregateData(Aggregate.HISTOGRAM, dataType);
         distinctValues.put(v, a);
       }
     }
     if (a != null) {
       a.count++;
     }
     return;
   }
   if (v == ValueNull.INSTANCE) {
     return;
   }
   count++;
   if (distinct) {
     if (distinctValues == null) {
       distinctValues = ValueHashMap.newInstance();
     }
     distinctValues.put(v, this);
     return;
   }
   switch (aggregateType) {
     case Aggregate.COUNT:
     case Aggregate.HISTOGRAM:
       return;
     case Aggregate.SUM:
       if (value == null) {
         value = v.convertTo(dataType);
       } else {
         v = v.convertTo(value.getType());
         value = value.add(v);
       }
       break;
     case Aggregate.AVG:
       if (value == null) {
         value = v.convertTo(DataType.getAddProofType(dataType));
       } else {
         v = v.convertTo(value.getType());
         value = value.add(v);
       }
       break;
     case Aggregate.MIN:
       if (value == null || database.compare(v, value) < 0) {
         value = v;
       }
       break;
     case Aggregate.MAX:
       if (value == null || database.compare(v, value) > 0) {
         value = v;
       }
       break;
     case Aggregate.GROUP_CONCAT:
       {
         if (list == null) {
           list = New.arrayList();
         }
         list.add(v);
         break;
       }
     case Aggregate.STDDEV_POP:
     case Aggregate.STDDEV_SAMP:
     case Aggregate.VAR_POP:
     case Aggregate.VAR_SAMP:
       {
         // Using Welford's method, see also
         // http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
         // http://www.johndcook.com/standard_deviation.html
         double x = v.getDouble();
         if (count == 1) {
           mean = x;
           m2 = 0;
         } else {
           double delta = x - mean;
           mean += delta / count;
           m2 += delta * (x - mean);
         }
         break;
       }
     case Aggregate.BOOL_AND:
       v = v.convertTo(Value.BOOLEAN);
       if (value == null) {
         value = v;
       } else {
         value =
             ValueBoolean.get(value.getBoolean().booleanValue() && v.getBoolean().booleanValue());
       }
       break;
     case Aggregate.BOOL_OR:
       v = v.convertTo(Value.BOOLEAN);
       if (value == null) {
         value = v;
       } else {
         value =
             ValueBoolean.get(value.getBoolean().booleanValue() || v.getBoolean().booleanValue());
       }
       break;
     default:
       DbException.throwInternalError("type=" + aggregateType);
   }
 }
Ejemplo n.º 2
0
 /**
  * Get the aggregate result.
  *
  * @param database the database
  * @param distinct if distinct is used
  * @return the value
  */
 Value getValue(Database database, boolean distinct) {
   if (distinct) {
     count = 0;
     groupDistinct(database);
   }
   Value v = null;
   switch (aggregateType) {
     case Aggregate.SELECTIVITY:
       {
         int s = 0;
         if (count == 0) {
           s = 0;
         } else {
           m2 += distinctHashes.size();
           m2 = 100 * m2 / count;
           s = (int) m2;
           s = s <= 0 ? 1 : s > 100 ? 100 : s;
         }
         v = ValueInt.get(s);
         break;
       }
     case Aggregate.COUNT:
     case Aggregate.COUNT_ALL:
       v = ValueLong.get(count);
       break;
     case Aggregate.SUM:
     case Aggregate.MIN:
     case Aggregate.MAX:
     case Aggregate.BOOL_OR:
     case Aggregate.BOOL_AND:
       v = value;
       break;
     case Aggregate.AVG:
       if (value != null) {
         v = divide(value, count);
       }
       break;
     case Aggregate.GROUP_CONCAT:
       return null;
     case Aggregate.STDDEV_POP:
       {
         if (count < 1) {
           return ValueNull.INSTANCE;
         }
         v = ValueDouble.get(Math.sqrt(m2 / count));
         break;
       }
     case Aggregate.STDDEV_SAMP:
       {
         if (count < 2) {
           return ValueNull.INSTANCE;
         }
         v = ValueDouble.get(Math.sqrt(m2 / (count - 1)));
         break;
       }
     case Aggregate.VAR_POP:
       {
         if (count < 1) {
           return ValueNull.INSTANCE;
         }
         v = ValueDouble.get(m2 / count);
         break;
       }
     case Aggregate.VAR_SAMP:
       {
         if (count < 2) {
           return ValueNull.INSTANCE;
         }
         v = ValueDouble.get(m2 / (count - 1));
         break;
       }
     case Aggregate.HISTOGRAM:
       ValueArray[] values = new ValueArray[distinctValues.size()];
       int i = 0;
       for (Value dv : distinctValues.keys()) {
         AggregateData d = distinctValues.get(dv);
         values[i] = ValueArray.get(new Value[] {dv, ValueLong.get(d.count)});
         i++;
       }
       final CompareMode compareMode = database.getCompareMode();
       Arrays.sort(
           values,
           new Comparator<ValueArray>() {
             public int compare(ValueArray v1, ValueArray v2) {
               Value a1 = v1.getList()[0];
               Value a2 = v2.getList()[0];
               return a1.compareTo(a2, compareMode);
             }
           });
       v = ValueArray.get(values);
       break;
     default:
       DbException.throwInternalError("type=" + aggregateType);
   }
   return v == null ? ValueNull.INSTANCE : v.convertTo(dataType);
 }