/**
* Returns the index of the first field in <code>rel</code> which comes from its <code>ordinal
* </code>th input.
*
* <p>For example, if rel joins T0(A,B,C) to T1(D,E), then countFields(0,rel) yields 0, and
* countFields(1,rel) yields 3.
*/
private int computeFieldOffset(RelNode rel, int ordinal) {
if (ordinal == 0) {
// short-circuit for the common case
return 0;
}
int fieldOffset = 0;
final List<RelNode> inputs = rel.getInputs();
for (int i = 0; i < ordinal; i++) {
RelNode input = inputs.get(i);
fieldOffset += input.getRowType().getFieldList().size();
}
return fieldOffset;
}
/**
* Returns the variable which, in the generated program, will hold the current row of a given
* relational expression. This method is only applicable if the relational expression is the
* current one or an input; if it is an ancestor, there is no current value, and this method
* returns null.
*/
public Variable findInputVariable(RelNode rel) {
while (true) {
JavaFrame frame = (JavaFrame) mapRel2Frame.get(rel);
if ((frame != null) && frame.hasVariable()) {
return frame.getVariable();
}
List<RelNode> inputs = rel.getInputs();
if (inputs.size() == 1) {
rel = inputs.get(0);
} else {
return null;
}
}
}
private JavaFrame findFrame() {
RelNode previous = rel;
while (true) {
JavaFrame frame = (JavaFrame) mapRel2Frame.get(previous);
if (frame.bind != null) {
tracer.log(
Level.FINE,
"Bind " + rel.toString() + " to " + previous.toString() + "(" + frame.bind + ")");
return frame;
}
// go deeper
List<RelNode> inputs = previous.getInputs();
assert (inputs.size() == 1) : "input is not bound";
previous = inputs.get(0);
}
}
protected void explain_(RelNode rel, List<Pair<String, Object>> values) {
final Map<String, Object> map = jsonBuilder.map();
map.put("id", null); // ensure that id is the first attribute
map.put("relOp", relJson.classToTypeName(rel.getClass()));
for (Pair<String, Object> value : values) {
if (value.right instanceof RelNode) {
continue;
}
put(map, value.left, value.right);
}
// omit 'inputs: ["3"]' if "3" is the preceding rel
final List<Object> list = explainInputs(rel.getInputs());
if (list.size() != 1 || !list.get(0).equals(previousId)) {
map.put("inputs", list);
}
final String id = Integer.toString(relIdMap.size());
relIdMap.put(rel, id);
map.put("id", id);
relList.add(map);
previousId = id;
}