Examples with RewriteProjectToFlatten org.apache.drill.exec.planner.physical.visitor.RewriteProjectToFlatten used on opensource projects

Example 1 with RewriteProjectToFlatten

use of org.apache.drill.exec.planner.physical.visitor.RewriteProjectToFlatten in project drill by apache.

the class DefaultSqlHandler method convertToPrel.

protected Prel convertToPrel(RelNode drel) throws RelConversionException, SqlUnsupportedException {
    Preconditions.checkArgument(drel.getConvention() == DrillRel.DRILL_LOGICAL);
    final RelTraitSet traits = drel.getTraitSet().plus(Prel.DRILL_PHYSICAL).plus(DrillDistributionTrait.SINGLETON);
    Prel phyRelNode;
    try {
        final Stopwatch watch = Stopwatch.createStarted();
        final RelNode relNode = transform(PlannerType.VOLCANO, PlannerPhase.PHYSICAL, drel, traits, false);
        phyRelNode = (Prel) relNode.accept(new PrelFinalizer());
        // log externally as we need to finalize before traversing the tree.
        log(PlannerType.VOLCANO, PlannerPhase.PHYSICAL, phyRelNode, logger, watch);
    } catch (RelOptPlanner.CannotPlanException ex) {
        logger.error(ex.getMessage());
        if (JoinUtils.checkCartesianJoin(drel, new ArrayList<Integer>(), new ArrayList<Integer>(), new ArrayList<Boolean>())) {
            throw new UnsupportedRelOperatorException("This query cannot be planned possibly due to either a cartesian join or an inequality join");
        } else {
            throw ex;
        }
    }
    OptionManager queryOptions = context.getOptions();
    if (context.getPlannerSettings().isMemoryEstimationEnabled() && !MemoryEstimationVisitor.enoughMemory(phyRelNode, queryOptions, context.getActiveEndpoints().size())) {
        log("Not enough memory for this plan", phyRelNode, logger, null);
        logger.debug("Re-planning without hash operations.");
        queryOptions.setOption(OptionValue.createBoolean(OptionValue.OptionType.QUERY, PlannerSettings.HASHJOIN.getOptionName(), false));
        queryOptions.setOption(OptionValue.createBoolean(OptionValue.OptionType.QUERY, PlannerSettings.HASHAGG.getOptionName(), false));
        try {
            final RelNode relNode = transform(PlannerType.VOLCANO, PlannerPhase.PHYSICAL, drel, traits);
            phyRelNode = (Prel) relNode.accept(new PrelFinalizer());
        } catch (RelOptPlanner.CannotPlanException ex) {
            logger.error(ex.getMessage());
            if (JoinUtils.checkCartesianJoin(drel, new ArrayList<Integer>(), new ArrayList<Integer>(), new ArrayList<Boolean>())) {
                throw new UnsupportedRelOperatorException("This query cannot be planned possibly due to either a cartesian join or an inequality join");
            } else {
                throw ex;
            }
        }
    }
    /* The order of the following transformations is important */
    /*
     * 0.) For select * from join query, we need insert project on top of scan and a top project just
     * under screen operator. The project on top of scan will rename from * to T1*, while the top project
     * will rename T1* to *, before it output the final result. Only the top project will allow
     * duplicate columns, since user could "explicitly" ask for duplicate columns ( select *, col, *).
     * The rest of projects will remove the duplicate column when we generate POP in json format.
     */
    phyRelNode = StarColumnConverter.insertRenameProject(phyRelNode);
    /*
     * 1.)
     * Join might cause naming conflicts from its left and right child.
     * In such case, we have to insert Project to rename the conflicting names.
     */
    phyRelNode = JoinPrelRenameVisitor.insertRenameProject(phyRelNode);
    /*
     * 1.1) Swap left / right for INNER hash join, if left's row count is < (1 + margin) right's row count.
     * We want to have smaller dataset on the right side, since hash table builds on right side.
     */
    if (context.getPlannerSettings().isHashJoinSwapEnabled()) {
        phyRelNode = SwapHashJoinVisitor.swapHashJoin(phyRelNode, new Double(context.getPlannerSettings().getHashJoinSwapMarginFactor()));
    }
    if (context.getPlannerSettings().isParquetRowGroupFilterPushdownPlanningEnabled()) {
        phyRelNode = (Prel) transform(PlannerType.HEP_BOTTOM_UP, PlannerPhase.PHYSICAL_PARTITION_PRUNING, phyRelNode);
    }
    /*
     * 1.2) Break up all expressions with complex outputs into their own project operations
     */
    phyRelNode = phyRelNode.accept(new SplitUpComplexExpressions(config.getConverter().getTypeFactory(), context.getDrillOperatorTable(), context.getPlannerSettings().functionImplementationRegistry), null);
    /*
     * 1.3) Projections that contain reference to flatten are rewritten as Flatten operators followed by Project
     */
    phyRelNode = phyRelNode.accept(new RewriteProjectToFlatten(config.getConverter().getTypeFactory(), context.getDrillOperatorTable()), null);
    /*
     * 2.)
     * Since our operators work via names rather than indices, we have to make to reorder any
     * output before we return data to the user as we may have accidentally shuffled things.
     * This adds a trivial project to reorder columns prior to output.
     */
    phyRelNode = FinalColumnReorderer.addFinalColumnOrdering(phyRelNode);
    /*
     * 3.)
     * If two fragments are both estimated to be parallelization one, remove the exchange
     * separating them
     */
    phyRelNode = ExcessiveExchangeIdentifier.removeExcessiveEchanges(phyRelNode, targetSliceSize);
    /* 5.)
     * if the client does not support complex types (Map, Repeated)
     * insert a project which which would convert
     */
    if (!context.getSession().isSupportComplexTypes()) {
        logger.debug("Client does not support complex types, add ComplexToJson operator.");
        phyRelNode = ComplexToJsonPrelVisitor.addComplexToJsonPrel(phyRelNode);
    }
    /* 6.)
     * Insert LocalExchange (mux and/or demux) nodes
     */
    phyRelNode = InsertLocalExchangeVisitor.insertLocalExchanges(phyRelNode, queryOptions);
    /* 7.)
     * Next, we add any required selection vector removers given the supported encodings of each
     * operator. This will ultimately move to a new trait but we're managing here for now to avoid
     * introducing new issues in planning before the next release
     */
    phyRelNode = SelectionVectorPrelVisitor.addSelectionRemoversWhereNecessary(phyRelNode);
    /* 8.)
     * Finally, Make sure that the no rels are repeats.
     * This could happen in the case of querying the same table twice as Optiq may canonicalize these.
     */
    phyRelNode = RelUniqifier.uniqifyGraph(phyRelNode);
    return phyRelNode;
}