private static SimpleResultSet getSimpleResultSet(ResultInterface rs, int maxrows) {
int columnCount = rs.getVisibleColumnCount();
SimpleResultSet simple = new SimpleResultSet();
for (int i = 0; i < columnCount; i++) {
String name = rs.getColumnName(i);
int sqlType = DataType.convertTypeToSQLType(rs.getColumnType(i));
int precision = MathUtils.convertLongToInt(rs.getColumnPrecision(i));
int scale = rs.getColumnScale(i);
simple.addColumn(name, sqlType, precision, scale);
}
rs.reset();
for (int i = 0; i < maxrows && rs.next(); i++) {
Object[] list = new Object[columnCount];
for (int j = 0; j < columnCount; j++) {
list[j] = rs.currentRow()[j].getObject();
}
simple.addRow(list);
}
return simple;
}
/**
* 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);
}
}
void merge(Database database, boolean distinct, Value v) {
if (aggregateType == Aggregate.COUNT || aggregateType == Aggregate.COUNT_ALL) {
count += v.getLong();
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:
case Aggregate.SELECTIVITY:
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 {
// AVG聚合函数merge的次数不会超过1
DbException.throwInternalError("type=" + aggregateType);
}
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:
{
v = v.convertTo(Value.DOUBLE);
if (value == null) {
value = v;
} else {
// 这4种聚合函数merge的次数不会超过1
DbException.throwInternalError("type=" + aggregateType);
}
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);
}
}