public boolean matches(RelOptRuleCall call) {
JoinRel join = (JoinRel) call.rels[0];
switch (join.getJoinType()) {
case INNER:
case LEFT:
return true;
case FULL:
case RIGHT:
return false;
default:
throw Util.unexpected(join.getJoinType());
}
}
public void onMatch(RelOptRuleCall call) {
assert matches(call);
final JoinRel join = (JoinRel) call.rels[0];
final List<Integer> leftKeys = new ArrayList<Integer>();
final List<Integer> rightKeys = new ArrayList<Integer>();
RelNode right = join.getRight();
final RelNode left = join.getLeft();
RexNode remainingCondition =
RelOptUtil.splitJoinCondition(left, right, join.getCondition(), leftKeys, rightKeys);
assert leftKeys.size() == rightKeys.size();
final List<CorrelatorRel.Correlation> correlationList =
new ArrayList<CorrelatorRel.Correlation>();
if (leftKeys.size() > 0) {
final RelOptCluster cluster = join.getCluster();
final RexBuilder rexBuilder = cluster.getRexBuilder();
int k = 0;
RexNode condition = null;
for (Integer leftKey : leftKeys) {
Integer rightKey = rightKeys.get(k++);
final String dyn_inIdStr = cluster.getQuery().createCorrel();
final int dyn_inId = RelOptQuery.getCorrelOrdinal(dyn_inIdStr);
// Create correlation to say 'each row, set variable #id
// to the value of column #leftKey'.
correlationList.add(new CorrelatorRel.Correlation(dyn_inId, leftKey));
condition =
RelOptUtil.andJoinFilters(
rexBuilder,
condition,
rexBuilder.makeCall(
SqlStdOperatorTable.equalsOperator,
rexBuilder.makeInputRef(
right.getRowType().getFieldList().get(rightKey).getType(), rightKey),
rexBuilder.makeCorrel(
left.getRowType().getFieldList().get(leftKey).getType(), dyn_inIdStr)));
}
right = CalcRel.createFilter(right, condition);
}
RelNode newRel =
new CorrelatorRel(
join.getCluster(),
left,
right,
remainingCondition,
correlationList,
join.getJoinType());
call.transformTo(newRel);
}
public void onMatch(RelOptRuleCall call) {
JoinRel join = (JoinRel) call.rels[0];
List<RexNode> expList = new ArrayList<RexNode>(Arrays.asList(join.getChildExps()));
if (reduceExpressions(join, expList)) {
call.transformTo(
new JoinRel(
join.getCluster(),
join.getLeft(),
join.getRight(),
expList.get(0),
join.getJoinType(),
join.getVariablesStopped()));
// New plan is absolutely better than old plan.
call.getPlanner().setImportance(join, 0.0);
}
}