// The output table's column names always follow the left table,
// where the output type is chosen based on DRILL's implicit casting rules
private void inferOutputFields() {
outputFields = Lists.newArrayList();
leftSchema = leftSide.getRecordBatch().getSchema();
rightSchema = rightSide.getRecordBatch().getSchema();
Iterator<MaterializedField> leftIter = leftSchema.iterator();
Iterator<MaterializedField> rightIter = rightSchema.iterator();
int index = 1;
while (leftIter.hasNext() && rightIter.hasNext()) {
MaterializedField leftField = leftIter.next();
MaterializedField rightField = rightIter.next();
if (hasSameTypeAndMode(leftField, rightField)) {
outputFields.add(MaterializedField.create(leftField.getPath(), leftField.getType()));
} else {
// If the output type is not the same,
// cast the column of one of the table to a data type which is the Least Restrictive
MinorType outputMinorType;
if (leftField.getType().getMinorType() == rightField.getType().getMinorType()) {
outputMinorType = leftField.getType().getMinorType();
} else {
List<MinorType> types = Lists.newLinkedList();
types.add(leftField.getType().getMinorType());
types.add(rightField.getType().getMinorType());
outputMinorType = TypeCastRules.getLeastRestrictiveType(types);
if (outputMinorType == null) {
throw new DrillRuntimeException(
"Type mismatch between "
+ leftField.getType().getMinorType().toString()
+ " on the left side and "
+ rightField.getType().getMinorType().toString()
+ " on the right side in column "
+ index
+ " of UNION ALL");
}
}
// The output data mode should be as flexible as the more flexible one from the two input
// tables
List<DataMode> dataModes = Lists.newLinkedList();
dataModes.add(leftField.getType().getMode());
dataModes.add(rightField.getType().getMode());
DataMode dataMode = TypeCastRules.getLeastRestrictiveDataMode(dataModes);
MajorType.Builder builder = MajorType.newBuilder();
builder.setMinorType(outputMinorType);
builder.setMode(dataMode);
outputFields.add(MaterializedField.create(leftField.getPath(), builder.build()));
}
++index;
}
assert !leftIter.hasNext() && !rightIter.hasNext()
: "Mis-match of column count should have been detected when validating sqlNode at planning";
}
public void updateColumnMetaData(
String catalogName,
String schemaName,
String tableName,
BatchSchema schema,
List<Class<?>> getObjectClasses) {
final List<ColumnMetaData> newColumns = new ArrayList<>(schema.getFieldCount());
for (int colOffset = 0; colOffset < schema.getFieldCount(); colOffset++) {
final MaterializedField field = schema.getColumn(colOffset);
Class<?> objectClass = getObjectClasses.get(colOffset);
final String columnName = field.getPath();
final MajorType rpcDataType = field.getType();
final AvaticaType bundledSqlDataType = getAvaticaType(rpcDataType);
final String columnClassName = objectClass.getName();
final int nullability;
switch (field.getDataMode()) {
case OPTIONAL:
nullability = ResultSetMetaData.columnNullable;
break;
case REQUIRED:
nullability = ResultSetMetaData.columnNoNulls;
break;
// Should REPEATED still map to columnNoNulls? or to columnNullable?
case REPEATED:
nullability = ResultSetMetaData.columnNoNulls;
break;
default:
throw new AssertionError(
"Unexpected new DataMode value '" + field.getDataMode().name() + "'");
}
final boolean isSigned = Types.isJdbcSignedType(rpcDataType);
// TODO(DRILL-3355): TODO(DRILL-3356): When string lengths, precisions,
// interval kinds, etc., are available from RPC-level data, implement:
// - precision for ResultSetMetadata.getPrecision(...) (like
// getColumns()'s COLUMN_SIZE)
// - scale for getScale(...), and
// - and displaySize for getColumnDisplaySize(...).
final int precision = rpcDataType.hasPrecision() ? rpcDataType.getPrecision() : 0;
final int scale = rpcDataType.hasScale() ? rpcDataType.getScale() : 0;
final int displaySize = 10;
ColumnMetaData col =
new ColumnMetaData(
colOffset, // (zero-based ordinal (for Java arrays/lists).)
false, /* autoIncrement */
false, /* caseSensitive */
true, /* searchable */
false, /* currency */
nullability,
isSigned,
displaySize,
columnName, /* label */
columnName, /* columnName */
schemaName,
precision,
scale,
tableName,
catalogName,
bundledSqlDataType,
true, /* readOnly */
false, /* writable */
false, /* definitelyWritable */
columnClassName);
newColumns.add(col);
}
columns = newColumns;
}
