Examples with UnionProcContext org.apache.hadoop.hive.ql.optimizer.unionproc.UnionProcContext used on opensource projects

Example 1 with UnionProcContext

use of org.apache.hadoop.hive.ql.optimizer.unionproc.UnionProcContext in project hive by apache.

the class GenMRUnion1 method process.

/**
   * Union Operator encountered . Currently, the algorithm is pretty simple: If
   * all the sub-queries are map-only, don't do anything. Otherwise, insert a
   * FileSink on top of all the sub-queries.
   *
   * This can be optimized later on.
   *
   * @param nd
   *          the file sink operator encountered
   * @param opProcCtx
   *          context
   */
@Override
public Object process(Node nd, Stack<Node> stack, NodeProcessorCtx opProcCtx, Object... nodeOutputs) throws SemanticException {
    UnionOperator union = (UnionOperator) nd;
    GenMRProcContext ctx = (GenMRProcContext) opProcCtx;
    ParseContext parseCtx = ctx.getParseCtx();
    UnionProcContext uCtx = parseCtx.getUCtx();
    // Map-only subqueries can be optimized in future to not write to a file in
    // future
    Map<Operator<? extends OperatorDesc>, GenMapRedCtx> mapCurrCtx = ctx.getMapCurrCtx();
    if (union.getConf().isAllInputsInSameReducer()) {
        // All inputs of this UnionOperator are in the same Reducer.
        // We do not need to break the operator tree.
        mapCurrCtx.put((Operator<? extends OperatorDesc>) nd, new GenMapRedCtx(ctx.getCurrTask(), ctx.getCurrAliasId()));
        return null;
    }
    UnionParseContext uPrsCtx = uCtx.getUnionParseContext(union);
    ctx.setCurrUnionOp(union);
    // map-reduce job
    if (uPrsCtx.allMapOnlySubQ()) {
        return processMapOnlyUnion(union, stack, ctx, uCtx);
    }
    assert uPrsCtx != null;
    Task<? extends Serializable> currTask = ctx.getCurrTask();
    int pos = UnionProcFactory.getPositionParent(union, stack);
    Task<? extends Serializable> uTask = null;
    MapredWork uPlan = null;
    // union is encountered for the first time
    GenMRUnionCtx uCtxTask = ctx.getUnionTask(union);
    if (uCtxTask == null) {
        uPlan = GenMapRedUtils.getMapRedWork(parseCtx);
        uTask = TaskFactory.get(uPlan, parseCtx.getConf());
        uCtxTask = new GenMRUnionCtx(uTask);
        ctx.setUnionTask(union, uCtxTask);
    } else {
        uTask = uCtxTask.getUTask();
    }
    // Copy into the current union task plan if
    if (uPrsCtx.getMapOnlySubq(pos) && uPrsCtx.getRootTask(pos)) {
        processSubQueryUnionMerge(ctx, uCtxTask, union, stack);
        if (ctx.getRootTasks().contains(currTask)) {
            ctx.getRootTasks().remove(currTask);
        }
    } else // If it a map-reduce job, create a temporary file
    {
        // is the current task a root task
        if (shouldBeRootTask(currTask) && !ctx.getRootTasks().contains(currTask) && (currTask.getParentTasks() == null || currTask.getParentTasks().isEmpty())) {
            ctx.getRootTasks().add(currTask);
        }
        processSubQueryUnionCreateIntermediate(union.getParentOperators().get(pos), union, uTask, ctx, uCtxTask);
        // the currAliasId and CurrTopOp is not valid any more
        ctx.setCurrAliasId(null);
        ctx.setCurrTopOp(null);
        ctx.getOpTaskMap().put(null, uTask);
    }
    ctx.setCurrTask(uTask);
    mapCurrCtx.put((Operator<? extends OperatorDesc>) nd, new GenMapRedCtx(ctx.getCurrTask(), null));
    return true;
}