Examples with DbGroupScan org.apache.drill.exec.physical.base.DbGroupScan used on opensource projects

Example 6 with DbGroupScan

use of org.apache.drill.exec.physical.base.DbGroupScan in project drill by apache.

the class IndexIntersectPlanGenerator method buildRestrictedDBScan.

private Pair<RelNode, DbGroupScan> buildRestrictedDBScan(RexNode remnant, boolean isAnyIndexAsync) {
    DbGroupScan origDbGroupScan = (DbGroupScan) IndexPlanUtils.getGroupScan(origScan);
    List<SchemaPath> cols = new ArrayList<SchemaPath>(origDbGroupScan.getColumns());
    if (!checkRowKey(cols)) {
        cols.add(origDbGroupScan.getRowKeyPath());
    }
    // Create a restricted groupscan from the primary table's groupscan
    DbGroupScan restrictedGroupScan = origDbGroupScan.getRestrictedScan(cols);
    if (restrictedGroupScan == null) {
        logger.error("Null restricted groupscan in IndexIntersectPlanGenerator.convertChild");
        return null;
    }
    DrillDistributionTrait partition = IndexPlanUtils.scanIsPartition(IndexPlanUtils.getGroupScan(origScan)) ? DrillDistributionTrait.RANDOM_DISTRIBUTED : DrillDistributionTrait.SINGLETON;
    RelNode lastRelNode;
    RelDataType dbscanRowType = convertRowType(origScan.getRowType(), origScan.getCluster().getTypeFactory());
    ScanPrel dbScan = new ScanPrel(origScan.getCluster(), origScan.getTraitSet().plus(Prel.DRILL_PHYSICAL).plus(partition), restrictedGroupScan, dbscanRowType, origScan.getTable());
    lastRelNode = dbScan;
    // build the row type for the left Project
    List<RexNode> leftProjectExprs = Lists.newArrayList();
    int leftRowKeyIndex = getRowKeyIndex(dbScan.getRowType(), origScan);
    final RelDataTypeField leftRowKeyField = dbScan.getRowType().getFieldList().get(leftRowKeyIndex);
    final RelDataTypeFactory.FieldInfoBuilder leftFieldTypeBuilder = dbScan.getCluster().getTypeFactory().builder();
    FilterPrel leftIndexFilterPrel = null;
    // full original condition.
    if (isAnyIndexAsync) {
        new FilterPrel(dbScan.getCluster(), dbScan.getTraitSet(), dbScan, indexContext.getOrigCondition());
        lastRelNode = leftIndexFilterPrel;
    }
    // new Project's rowtype is original Project's rowtype [plus rowkey if rowkey is not in original rowtype]
    ProjectPrel leftIndexProjectPrel = null;
    if (origProject != null) {
        RelDataType origRowType = origProject.getRowType();
        List<RelDataTypeField> origProjFields = origRowType.getFieldList();
        leftFieldTypeBuilder.addAll(origProjFields);
        // get the exprs from the original Project IFF there is a project
        leftProjectExprs.addAll(IndexPlanUtils.getProjects(origProject));
        // add the rowkey IFF rowkey is not in orig scan
        if (getRowKeyIndex(origRowType, origScan) < 0) {
            leftFieldTypeBuilder.add(leftRowKeyField);
            leftProjectExprs.add(RexInputRef.of(leftRowKeyIndex, dbScan.getRowType()));
        }
        final RelDataType leftProjectRowType = leftFieldTypeBuilder.build();
        leftIndexProjectPrel = new ProjectPrel(dbScan.getCluster(), dbScan.getTraitSet(), leftIndexFilterPrel == null ? dbScan : leftIndexFilterPrel, leftProjectExprs, leftProjectRowType);
        lastRelNode = leftIndexProjectPrel;
    }
    final RelTraitSet leftTraits = dbScan.getTraitSet().plus(Prel.DRILL_PHYSICAL);
    // final RelNode convertedLeft = convert(leftIndexProjectPrel, leftTraits);
    final RelNode convertedLeft = Prule.convert(lastRelNode, leftTraits);
    return new Pair<>(convertedLeft, restrictedGroupScan);
}

Example 7 with DbGroupScan

use of org.apache.drill.exec.physical.base.DbGroupScan in project drill by apache.

the class IndexIntersectPlanGenerator method convertChild.

@Override
public RelNode convertChild(final RelNode filter, final RelNode input) throws InvalidRelException {
    Map<IndexDescriptor, RexNode> idxConditionMap = Maps.newLinkedHashMap();
    boolean isAnyIndexAsync = false;
    for (IndexDescriptor idx : indexInfoMap.keySet()) {
        idxConditionMap.put(idx, indexInfoMap.get(idx).indexCondition);
        if (!isAnyIndexAsync && idx.isAsyncIndex()) {
            isAnyIndexAsync = true;
        }
    }
    RelNode indexPlan = null;
    boolean generateDistribution;
    int curIdx = 0;
    RexNode remnant = indexContext.getFilterCondition();
    for (Map.Entry<IndexDescriptor, RexNode> pair : idxConditionMap.entrySet()) {
        // For the last index, the generated join is distributed using createRangeDistRight instead!
        generateDistribution = (idxConditionMap.entrySet().size() - 1 - curIdx) > 0;
        indexPlan = buildIntersectPlan(pair, indexPlan, generateDistribution);
        remnant = indexInfoMap.get(pair.getKey()).remainderCondition;
        ++curIdx;
    }
    final RelDataTypeField rightRowKeyField = indexPlan.getRowType().getFieldList().get(0);
    final RelNode rangeDistRight = createRangeDistRight(indexPlan, rightRowKeyField, (DbGroupScan) IndexPlanUtils.getGroupScan(origScan));
    // now with index plan constructed, build plan of left(probe) side to use restricted db scan
    Pair<RelNode, DbGroupScan> leftRelAndScan = buildRestrictedDBScan(remnant, isAnyIndexAsync);
    RelNode finalRel = buildRowKeyJoin(leftRelAndScan.left, rangeDistRight, true, JoinControl.DEFAULT);
    if (upperProject != null) {
        ProjectPrel cap = new ProjectPrel(finalRel.getCluster(), finalRel.getTraitSet(), finalRel, IndexPlanUtils.getProjects(upperProject), upperProject.getRowType());
        finalRel = cap;
    }
    return finalRel;
}

Example 8 with DbGroupScan

use of org.apache.drill.exec.physical.base.DbGroupScan in project drill by apache.

the class IndexPlanUtils method isCoveringIndex.

/**
 * For a particular table scan for table T1 and an index on that table, find out if it is a covering index
 * @return true if it is a covering index, otherwise false
 */
public static boolean isCoveringIndex(IndexCallContext indexContext, FunctionalIndexInfo functionInfo) {
    if (functionInfo.hasFunctional()) {
        // need info from full query
        return queryCoveredByIndex(indexContext, functionInfo);
    }
    DbGroupScan groupScan = (DbGroupScan) getGroupScan(indexContext.getScan());
    List<LogicalExpression> tableCols = Lists.newArrayList();
    tableCols.addAll(groupScan.getColumns());
    return functionInfo.getIndexDesc().isCoveringIndex(tableCols);
}

Example 9 with DbGroupScan

use of org.apache.drill.exec.physical.base.DbGroupScan in project drill by apache.

the class NonCoveringIndexPlanGenerator method convertChild.

@Override
public RelNode convertChild(final RelNode topRel, final RelNode input) throws InvalidRelException {
    if (indexGroupScan == null) {
        logger.error("Null indexgroupScan in NonCoveringIndexPlanGenerator.convertChild");
        return null;
    }
    RelDataType dbscanRowType = convertRowType(origScan.getRowType(), origScan.getCluster().getTypeFactory());
    RelDataType indexScanRowType = FunctionalIndexHelper.convertRowTypeForIndexScan(origScan, indexContext.getOrigMarker(), indexGroupScan, functionInfo);
    DrillDistributionTrait partition = IndexPlanUtils.scanIsPartition(IndexPlanUtils.getGroupScan(origScan)) ? DrillDistributionTrait.RANDOM_DISTRIBUTED : DrillDistributionTrait.SINGLETON;
    ScanPrel indexScanPrel = new ScanPrel(origScan.getCluster(), origScan.getTraitSet().plus(Prel.DRILL_PHYSICAL).plus(partition), indexGroupScan, indexScanRowType, origScan.getTable());
    DbGroupScan origDbGroupScan = (DbGroupScan) IndexPlanUtils.getGroupScan(origScan);
    // right (build) side of the rowkey join: do a distribution of project-filter-indexscan subplan
    RexNode convertedIndexCondition = FunctionalIndexHelper.convertConditionForIndexScan(indexCondition, origScan, indexScanRowType, builder, functionInfo);
    FilterPrel rightIndexFilterPrel = new FilterPrel(indexScanPrel.getCluster(), indexScanPrel.getTraitSet(), indexScanPrel, convertedIndexCondition);
    double finalRowCount = indexGroupScan.getRowCount(indexContext.getOrigCondition(), origScan);
    // project the rowkey column from the index scan
    List<RexNode> rightProjectExprs = Lists.newArrayList();
    // indexGroupScan.getRowKeyOrdinal();
    int rightRowKeyIndex = getRowKeyIndex(indexScanPrel.getRowType(), origScan);
    assert rightRowKeyIndex >= 0;
    rightProjectExprs.add(RexInputRef.of(rightRowKeyIndex, indexScanPrel.getRowType()));
    final List<RelDataTypeField> indexScanFields = indexScanPrel.getRowType().getFieldList();
    final RelDataTypeFactory.FieldInfoBuilder rightFieldTypeBuilder = indexScanPrel.getCluster().getTypeFactory().builder();
    // build the row type for the right Project
    final RelDataTypeField rightRowKeyField = indexScanFields.get(rightRowKeyIndex);
    rightFieldTypeBuilder.add(rightRowKeyField);
    final RelDataType rightProjectRowType = rightFieldTypeBuilder.build();
    final ProjectPrel rightIndexProjectPrel = new ProjectPrel(indexScanPrel.getCluster(), indexScanPrel.getTraitSet(), rightIndexFilterPrel, rightProjectExprs, rightProjectRowType);
    // create a RANGE PARTITION on the right side (this could be removed later during ExcessiveExchangeIdentifier phase
    // if the estimated row count is smaller than slice_target
    final RelNode rangeDistRight = createRangeDistRight(rightIndexProjectPrel, rightRowKeyField, origDbGroupScan);
    // the range partitioning adds an extra column for the partition id but in the final plan we already have a
    // renaming Project for the _id field inserted as part of the JoinPrelRenameVisitor. Thus, we are not inserting
    // a separate Project here.
    final RelNode convertedRight = rangeDistRight;
    // left (probe) side of the rowkey join
    List<SchemaPath> cols = new ArrayList<SchemaPath>(origDbGroupScan.getColumns());
    if (!checkRowKey(cols)) {
        cols.add(origDbGroupScan.getRowKeyPath());
    }
    // Create a restricted groupscan from the primary table's groupscan
    DbGroupScan restrictedGroupScan = (DbGroupScan) origDbGroupScan.getRestrictedScan(cols);
    if (restrictedGroupScan == null) {
        logger.error("Null restricted groupscan in NonCoveringIndexPlanGenerator.convertChild");
        return null;
    }
    // Set left side (restricted scan) row count as rows returned from right side (index scan)
    DrillScanRel rightIdxRel = new DrillScanRel(origScan.getCluster(), origScan.getTraitSet(), origScan.getTable(), origScan.getRowType(), indexContext.getScanColumns());
    double rightIdxRowCount = indexGroupScan.getRowCount(indexCondition, rightIdxRel);
    restrictedGroupScan.setRowCount(null, rightIdxRowCount, rightIdxRowCount);
    RelTraitSet origScanTraitSet = origScan.getTraitSet();
    RelTraitSet restrictedScanTraitSet = origScanTraitSet.plus(Prel.DRILL_PHYSICAL);
    // Create the collation traits for restricted scan based on the index columns under the
    // conditions that (a) the index actually has collation property (e.g hash indexes don't)
    // and (b) if an explicit sort operation is not enforced
    RelCollation collation = null;
    if (indexDesc.getCollation() != null && !settings.isIndexForceSortNonCovering()) {
        collation = IndexPlanUtils.buildCollationNonCoveringIndexScan(indexDesc, indexScanRowType, dbscanRowType, indexContext);
        if (restrictedScanTraitSet.contains(RelCollationTraitDef.INSTANCE)) {
            // replace existing trait
            restrictedScanTraitSet = restrictedScanTraitSet.plus(partition).replace(collation);
        } else {
            // add new one
            restrictedScanTraitSet = restrictedScanTraitSet.plus(partition).plus(collation);
        }
    }
    ScanPrel dbScan = new ScanPrel(origScan.getCluster(), restrictedScanTraitSet, restrictedGroupScan, dbscanRowType, origScan.getTable());
    RelNode lastLeft = dbScan;
    // build the row type for the left Project
    List<RexNode> leftProjectExprs = Lists.newArrayList();
    int leftRowKeyIndex = getRowKeyIndex(dbScan.getRowType(), origScan);
    final RelDataTypeField leftRowKeyField = dbScan.getRowType().getFieldList().get(leftRowKeyIndex);
    final RelDataTypeFactory.FieldInfoBuilder leftFieldTypeBuilder = dbScan.getCluster().getTypeFactory().builder();
    // We are applying the same index condition to primary table's restricted scan. The reason is, the index may be an async
    // index .. i.e it is not synchronously updated along with the primary table update as part of a single transaction, so it
    // is possible that after or during index scan, the primary table rows may have been updated and no longer satisfy the index
    // condition. By re-applying the index condition here, we will ensure non-qualifying records are filtered out.
    // The remainder condition will be applied on top of RowKeyJoin.
    FilterPrel leftIndexFilterPrel = null;
    if (indexDesc.isAsyncIndex()) {
        leftIndexFilterPrel = new FilterPrel(dbScan.getCluster(), dbScan.getTraitSet(), dbScan, indexContext.getOrigCondition());
        lastLeft = leftIndexFilterPrel;
    }
    RelDataType origRowType = origProject == null ? origScan.getRowType() : origProject.getRowType();
    if (origProject != null) {
        // then we also  don't need a project
        // new Project's rowtype is original Project's rowtype [plus rowkey if rowkey is not in original rowtype]
        List<RelDataTypeField> origProjFields = origRowType.getFieldList();
        leftFieldTypeBuilder.addAll(origProjFields);
        // get the exprs from the original Project
        leftProjectExprs.addAll(IndexPlanUtils.getProjects(origProject));
        // add the rowkey IFF rowkey is not in orig scan
        if (getRowKeyIndex(origRowType, origScan) < 0) {
            leftFieldTypeBuilder.add(leftRowKeyField);
            leftProjectExprs.add(RexInputRef.of(leftRowKeyIndex, dbScan.getRowType()));
        }
        final RelDataType leftProjectRowType = leftFieldTypeBuilder.build();
        // build collation in project
        if (!settings.isIndexForceSortNonCovering()) {
            collation = IndexPlanUtils.buildCollationProject(leftProjectExprs, null, dbScan, functionInfo, indexContext);
        }
        final ProjectPrel leftIndexProjectPrel = new ProjectPrel(dbScan.getCluster(), collation != null ? dbScan.getTraitSet().plus(collation) : dbScan.getTraitSet(), leftIndexFilterPrel == null ? dbScan : leftIndexFilterPrel, leftProjectExprs, leftProjectRowType);
        lastLeft = leftIndexProjectPrel;
    }
    final RelTraitSet leftTraits = dbScan.getTraitSet().plus(Prel.DRILL_PHYSICAL);
    // final RelNode convertedLeft = convert(leftIndexProjectPrel, leftTraits);
    final RelNode convertedLeft = Prule.convert(lastLeft, leftTraits);
    // find the rowkey column on the left side of join
    final int leftRowKeyIdx = getRowKeyIndex(convertedLeft.getRowType(), origScan);
    // only rowkey field is being projected from right side
    final int rightRowKeyIdx = 0;
    assert leftRowKeyIdx >= 0;
    List<Integer> leftJoinKeys = ImmutableList.of(leftRowKeyIdx);
    List<Integer> rightJoinKeys = ImmutableList.of(rightRowKeyIdx);
    RexNode joinCondition = RelOptUtil.createEquiJoinCondition(convertedLeft, leftJoinKeys, convertedRight, rightJoinKeys, builder);
    RelNode newRel;
    if (settings.isIndexUseHashJoinNonCovering()) {
        // for hash join, collation will be cleared
        HashJoinPrel hjPrel = new HashJoinPrel(topRel.getCluster(), leftTraits, convertedLeft, convertedRight, joinCondition, JoinRelType.INNER, false, /* no swap */
        null, /* no runtime filter */
        true, /* useful for join-restricted scans */
        JoinControl.DEFAULT);
        newRel = hjPrel;
    } else {
        // if there is collation, add to rowkey join
        RowKeyJoinPrel rjPrel = new RowKeyJoinPrel(topRel.getCluster(), collation != null ? leftTraits.plus(collation) : leftTraits, convertedLeft, convertedRight, joinCondition, JoinRelType.INNER);
        rjPrel.setEstimatedRowCount(finalRowCount);
        newRel = rjPrel;
    }
    final RelDataTypeFactory.FieldInfoBuilder finalFieldTypeBuilder = origScan.getCluster().getTypeFactory().builder();
    List<RelDataTypeField> rjRowFields = newRel.getRowType().getFieldList();
    int toRemoveRowKeyCount = 1;
    if (getRowKeyIndex(origRowType, origScan) < 0) {
        toRemoveRowKeyCount = 2;
    }
    finalFieldTypeBuilder.addAll(rjRowFields.subList(0, rjRowFields.size() - toRemoveRowKeyCount));
    final RelDataType finalProjectRowType = finalFieldTypeBuilder.build();
    List<RexNode> resetExprs = Lists.newArrayList();
    for (int idx = 0; idx < rjRowFields.size() - toRemoveRowKeyCount; ++idx) {
        resetExprs.add(RexInputRef.of(idx, newRel.getRowType()));
    }
    // rewrite the collation for this projectPrel
    final ProjectPrel resetProjectPrel = new ProjectPrel(newRel.getCluster(), newRel.getTraitSet(), newRel, resetExprs, finalProjectRowType);
    newRel = resetProjectPrel;
    if (upperProject != null) {
        RelCollation newCollation = RelCollations.of(RelCollations.EMPTY.getFieldCollations());
        DrillDistributionTrait newDist = null;
        newDist = upperProject.getInput().getTraitSet().getTrait(DrillDistributionTraitDef.INSTANCE);
        if (!settings.isIndexForceSortNonCovering()) {
            newCollation = IndexPlanUtils.buildCollationProject(IndexPlanUtils.getProjects(upperProject), origProject, origScan, functionInfo, indexContext);
        }
        RelTraitSet newProjectTraits = newTraitSet(Prel.DRILL_PHYSICAL, newDist, newCollation);
        ProjectPrel cap = new ProjectPrel(upperProject.getCluster(), newProjectTraits, newRel, IndexPlanUtils.getProjects(upperProject), upperProject.getRowType());
        newRel = cap;
    }
    // whether to remove sort
    if (indexContext.getSort() != null) {
        // unsorted input because ordering is not guaranteed across different parallel inputs.
        if (toRemoveSort(indexContext.getCollation(), newRel.getTraitSet().getTrait(RelCollationTraitDef.INSTANCE))) {
            ((IndexGroupScan) indexScanPrel.getGroupScan()).setParallelizationWidth(1);
        }
        newRel = getSortNode(indexContext, newRel, false, true, true);
        Preconditions.checkArgument(newRel != null);
    }
    RelNode finalRel = Prule.convert(newRel, newRel.getTraitSet());
    logger.debug("NonCoveringIndexPlanGenerator got finalRel {} from origScan {}", finalRel.toString(), origScan.toString());
    return finalRel;
}

Example 10 with DbGroupScan

use of org.apache.drill.exec.physical.base.DbGroupScan in project drill by apache.

the class DbScanToIndexScanPrule method processWithIndexSelection.

private void processWithIndexSelection(IndexLogicalPlanCallContext indexContext, PlannerSettings settings, RexNode condition, IndexCollection collection, RexBuilder builder) {
    double totalRows = 0;
    double filterRows = totalRows;
    DrillScanRel scan = indexContext.scan;
    if (!(indexContext.scan.getGroupScan() instanceof DbGroupScan)) {
        return;
    }
    IndexConditionInfo.Builder infoBuilder = IndexConditionInfo.newBuilder(condition, collection, builder, indexContext.scan);
    IndexConditionInfo cInfo = infoBuilder.getCollectiveInfo(indexContext);
    boolean isValidIndexHint = infoBuilder.isValidIndexHint(indexContext);
    if (!cInfo.hasIndexCol) {
        logger.info("index_plan_info: No index columns are projected from the scan..continue.");
        return;
    }
    if (cInfo.indexCondition == null) {
        logger.info("index_plan_info: No conditions were found eligible for applying index lookup.");
        return;
    }
    if (!indexContext.indexHint.equals("") && !isValidIndexHint) {
        logger.warn("index_plan_info: Index Hint {} is not useful as index with that name is not available", indexContext.indexHint);
    }
    RexNode indexCondition = cInfo.indexCondition;
    RexNode remainderCondition = cInfo.remainderCondition;
    if (remainderCondition.isAlwaysTrue()) {
        remainderCondition = null;
    }
    logger.debug("index_plan_info: condition split into indexcondition: {} and remaindercondition: {}", indexCondition, remainderCondition);
    IndexableExprMarker indexableExprMarker = new IndexableExprMarker(indexContext.scan);
    indexCondition.accept(indexableExprMarker);
    indexContext.origMarker = indexableExprMarker;
    if (scan.getGroupScan() instanceof DbGroupScan) {
        // Initialize statistics
        DbGroupScan dbScan = ((DbGroupScan) scan.getGroupScan());
        if (settings.isStatisticsEnabled()) {
            dbScan.getStatistics().initialize(condition, scan, indexContext);
        }
        totalRows = dbScan.getRowCount(null, scan);
        filterRows = dbScan.getRowCount(condition, scan);
        double sel = filterRows / totalRows;
        if (totalRows != Statistics.ROWCOUNT_UNKNOWN && filterRows != Statistics.ROWCOUNT_UNKNOWN && !settings.isDisableFullTableScan() && !isValidIndexHint && sel > Math.max(settings.getIndexCoveringSelThreshold(), settings.getIndexNonCoveringSelThreshold())) {
            // If full table scan is not disabled, generate full table scan only plans if selectivity
            // is greater than covering and non-covering selectivity thresholds
            logger.info("index_plan_info: Skip index planning because filter selectivity: {} is greater than thresholds {}, {}", sel, settings.getIndexCoveringSelThreshold(), settings.getIndexNonCoveringSelThreshold());
            return;
        }
    }
    if (totalRows == Statistics.ROWCOUNT_UNKNOWN || totalRows == 0 || filterRows == Statistics.ROWCOUNT_UNKNOWN) {
        logger.warn("index_plan_info: Total row count is UNKNOWN or 0, or filterRows UNKNOWN; skip index planning");
        return;
    }
    List<IndexGroup> coveringIndexes = Lists.newArrayList();
    List<IndexGroup> nonCoveringIndexes = Lists.newArrayList();
    List<IndexGroup> intersectIndexes = Lists.newArrayList();
    // update sort expressions in context, it is needed for computing collation, so do it before IndexSelector
    IndexPlanUtils.updateSortExpression(indexContext, indexContext.sort != null ? indexContext.sort.collation.getFieldCollations() : null);
    IndexSelector selector = new IndexSelector(indexCondition, remainderCondition, indexContext, collection, builder, totalRows);
    for (IndexDescriptor indexDesc : collection) {
        logger.info("index_plan_info indexDescriptor: {}", indexDesc.toString());
        // check if any of the indexed fields of the index are present in the filter condition
        if (IndexPlanUtils.conditionIndexed(indexableExprMarker, indexDesc) != IndexPlanUtils.ConditionIndexed.NONE) {
            if (isValidIndexHint && !indexContext.indexHint.equals(indexDesc.getIndexName())) {
                logger.info("index_plan_info: Index {} is being discarded due to index Hint", indexDesc.getIndexName());
                continue;
            }
            FunctionalIndexInfo functionInfo = indexDesc.getFunctionalInfo();
            selector.addIndex(indexDesc, IndexPlanUtils.isCoveringIndex(indexContext, functionInfo), indexContext.lowerProject != null ? indexContext.lowerProject.getRowType().getFieldCount() : scan.getRowType().getFieldCount());
        }
    }
    // get the candidate indexes based on selection
    selector.getCandidateIndexes(infoBuilder, coveringIndexes, nonCoveringIndexes, intersectIndexes);
    if (logger.isDebugEnabled()) {
        StringBuilder strb = new StringBuilder();
        if (coveringIndexes.size() > 0) {
            strb.append("Covering indexes:");
            for (IndexGroup index : coveringIndexes) {
                strb.append(index.getIndexProps().get(0).getIndexDesc().getIndexName()).append(", ");
            }
        }
        if (nonCoveringIndexes.size() > 0) {
            strb.append("Non-covering indexes:");
            for (IndexGroup index : nonCoveringIndexes) {
                strb.append(index.getIndexProps().get(0).getIndexDesc().getIndexName()).append(", ");
            }
        }
        logger.debug("index_plan_info: IndexSelector return: {}", strb.toString());
    }
    GroupScan primaryTableScan = indexContext.scan.getGroupScan();
    // TODO: this logic for intersect should eventually be migrated to the IndexSelector
    if (coveringIndexes.size() == 0 && nonCoveringIndexes.size() > 1) {
        List<IndexDescriptor> indexList = Lists.newArrayList();
        for (IndexGroup index : nonCoveringIndexes) {
            IndexDescriptor indexDesc = index.getIndexProps().get(0).getIndexDesc();
            IndexGroupScan idxScan = indexDesc.getIndexGroupScan();
            // Copy primary table statistics to index table
            idxScan.setStatistics(((DbGroupScan) primaryTableScan).getStatistics());
            indexList.add(index.getIndexProps().get(0).getIndexDesc());
        }
        Map<IndexDescriptor, IndexConditionInfo> indexInfoMap = infoBuilder.getIndexConditionMap(indexList);
        // no usable index
        if (indexInfoMap == null || indexInfoMap.size() == 0) {
            logger.info("index_plan_info: skipping intersect plan generation as there is no usable index");
            return;
        }
        // some part of filter condition needs to apply on primary table.
        if (indexInfoMap.size() > 1) {
            logger.info("index_plan_info: intersect plan is generated");
            if (logger.isDebugEnabled()) {
                List<String> indices = new ArrayList<>(nonCoveringIndexes.size());
                for (IndexGroup index : nonCoveringIndexes) {
                    indices.add(index.getIndexProps().get(0).getIndexDesc().getIndexName());
                }
                logger.debug("index_plan_info: intersect plan is generated on index list {}", indices);
            }
            boolean intersectPlanGenerated = false;
            // TODO: make sure the smallest selectivity of these indexes times rowcount smaller than broadcast threshold
            for (IndexGroup index : intersectIndexes) {
                List<IndexDescriptor> candidateDesc = Lists.newArrayList();
                for (IndexProperties candProp : index.getIndexProps()) {
                    candidateDesc.add(candProp.getIndexDesc());
                }
                Map<IndexDescriptor, IndexConditionInfo> intersectIdxInfoMap = infoBuilder.getIndexConditionMap(candidateDesc);
                IndexIntersectPlanGenerator planGen = new IndexIntersectPlanGenerator(indexContext, intersectIdxInfoMap, builder, settings);
                try {
                    planGen.go();
                    intersectPlanGenerated = true;
                } catch (Exception e) {
                    // If error while generating intersect plans, continue onto generating non-covering plans
                    logger.warn("index_plan_info: Exception while trying to generate intersect index plan", e);
                }
            }
            // If intersect plans are forced do not generate further non-covering plans
            if (intersectPlanGenerated && settings.isIndexIntersectPlanPreferred()) {
                return;
            }
        }
    }
    try {
        for (IndexGroup index : coveringIndexes) {
            IndexProperties indexProps = index.getIndexProps().get(0);
            IndexDescriptor indexDesc = indexProps.getIndexDesc();
            IndexGroupScan idxScan = indexDesc.getIndexGroupScan();
            FunctionalIndexInfo indexInfo = indexDesc.getFunctionalInfo();
            indexCondition = indexProps.getLeadingColumnsFilter();
            remainderCondition = indexProps.getTotalRemainderFilter();
            // Copy primary table statistics to index table
            idxScan.setStatistics(((DbGroupScan) scan.getGroupScan()).getStatistics());
            logger.info("index_plan_info: Generating covering index plan for index: {}, query condition {}", indexDesc.getIndexName(), indexCondition.toString());
            CoveringIndexPlanGenerator planGen = new CoveringIndexPlanGenerator(indexContext, indexInfo, idxScan, indexCondition, remainderCondition, builder, settings);
            planGen.go();
        }
    } catch (Exception e) {
        logger.warn("Exception while trying to generate covering index plan", e);
    }
    // First, check if the primary table scan supports creating a restricted scan
    if (primaryTableScan instanceof DbGroupScan && (((DbGroupScan) primaryTableScan).supportsRestrictedScan())) {
        try {
            for (IndexGroup index : nonCoveringIndexes) {
                IndexProperties indexProps = index.getIndexProps().get(0);
                IndexDescriptor indexDesc = indexProps.getIndexDesc();
                IndexGroupScan idxScan = indexDesc.getIndexGroupScan();
                indexCondition = indexProps.getLeadingColumnsFilter();
                remainderCondition = indexProps.getTotalRemainderFilter();
                // Copy primary table statistics to index table
                idxScan.setStatistics(((DbGroupScan) primaryTableScan).getStatistics());
                logger.info("index_plan_info: Generating non-covering index plan for index: {}, query condition {}", indexDesc.getIndexName(), indexCondition.toString());
                NonCoveringIndexPlanGenerator planGen = new NonCoveringIndexPlanGenerator(indexContext, indexDesc, idxScan, indexCondition, remainderCondition, builder, settings);
                planGen.go();
            }
        } catch (Exception e) {
            logger.warn("Exception while trying to generate non-covering index access plan", e);
        }
    }
}