* The Node Processor for Column Pruning on Reduce Sink Operators.
*/
public static class ColumnPrunerReduceSinkProc implements NodeProcessor {
public Object process(Node nd, Stack<Node> stack, NodeProcessorCtx ctx,
Object... nodeOutputs) throws SemanticException {
ReduceSinkOperator op = (ReduceSinkOperator) nd;
ColumnPrunerProcCtx cppCtx = (ColumnPrunerProcCtx) ctx;
HashMap<Operator<? extends OperatorDesc>, OpParseContext> opToParseCtxMap = cppCtx
.getOpToParseCtxMap();
RowResolver redSinkRR = opToParseCtxMap.get(op).getRowResolver();
ReduceSinkDesc conf = op.getConf();
List<Operator<? extends OperatorDesc>> childOperators = op
.getChildOperators();
List<Operator<? extends OperatorDesc>> parentOperators = op
.getParentOperators();
List<String> colLists = new ArrayList<String>();
ArrayList<ExprNodeDesc> keys = conf.getKeyCols();
for (ExprNodeDesc key : keys) {
colLists = Utilities.mergeUniqElems(colLists, key.getCols());
}
if ((childOperators.size() == 1)
&& (childOperators.get(0) instanceof JoinOperator)) {
assert parentOperators.size() == 1;
Operator<? extends OperatorDesc> par = parentOperators.get(0);
JoinOperator childJoin = (JoinOperator) childOperators.get(0);
RowResolver parRR = opToParseCtxMap.get(par).getRowResolver();
List<String> childJoinCols = cppCtx.getJoinPrunedColLists().get(
childJoin).get((byte) conf.getTag());
boolean[] flags = new boolean[conf.getValueCols().size()];
for (int i = 0; i < flags.length; i++) {
flags[i] = false;
}
if (childJoinCols != null && childJoinCols.size() > 0) {
Map<String, ExprNodeDesc> exprMap = op.getColumnExprMap();
for (String childCol : childJoinCols) {
ExprNodeDesc desc = exprMap.get(childCol);
int index = conf.getValueCols().indexOf(desc);
flags[index] = true;
String[] nm = redSinkRR.reverseLookup(childCol);