Examples with AbstractScanPlanNode org.voltdb.plannodes.AbstractScanPlanNode used on opensource projects

Example 1 with AbstractScanPlanNode

use of org.voltdb.plannodes.AbstractScanPlanNode in project voltdb by VoltDB.

the class ReplaceWithIndexLimit method recursivelyApply.

@Override
protected AbstractPlanNode recursivelyApply(AbstractPlanNode plan) {
    assert (plan != null);
    // depth first:
    //     Find AggregatePlanNode with exactly one child
    //     where that child is an AbstractScanPlanNode.
    //     Replace qualifying SeqScanPlanNode with an
    //     IndexScanPlanNode with an inlined LimitPlanNode;
    //     or appending the LimitPlanNode to the existing
    //     qualified IndexScanPlanNode.
    ArrayList<AbstractPlanNode> children = new ArrayList<AbstractPlanNode>();
    for (int i = 0; i < plan.getChildCount(); i++) children.add(plan.getChild(i));
    for (AbstractPlanNode child : children) {
        // TODO this will break when children feed multiple parents
        AbstractPlanNode newChild = recursivelyApply(child);
        // Do a graft into the (parent) plan only if a replacement for a child was found.
        if (newChild == child) {
            continue;
        }
        child.removeFromGraph();
        plan.addAndLinkChild(newChild);
    }
    // check for an aggregation of the right form
    if ((plan instanceof AggregatePlanNode) == false)
        return plan;
    assert (plan.getChildCount() == 1);
    AggregatePlanNode aggplan = (AggregatePlanNode) plan;
    // handle one single min() / max() now
    // TODO: combination of [min(), max(), count()]
    SortDirectionType sortDirection = SortDirectionType.INVALID;
    if (aggplan.isTableMin()) {
        sortDirection = SortDirectionType.ASC;
    } else if (aggplan.isTableMax()) {
        sortDirection = SortDirectionType.DESC;
    } else {
        return plan;
    }
    AbstractPlanNode child = plan.getChild(0);
    AbstractExpression aggExpr = aggplan.getFirstAggregateExpression();
    // for a SEQSCAN, replace it with a INDEXSCAN node with an inline LIMIT plan node
    if (child instanceof SeqScanPlanNode) {
        // should have other index access plan if any qualified index found for the predicate
        if (((SeqScanPlanNode) child).getPredicate() != null) {
            return plan;
        }
        if (((AbstractScanPlanNode) child).isSubQuery()) {
            return plan;
        }
        // create an empty bindingExprs list, used for store (possible) bindings for adHoc query
        ArrayList<AbstractExpression> bindings = new ArrayList<AbstractExpression>();
        Index ret = findQualifiedIndex(((SeqScanPlanNode) child), aggExpr, bindings);
        if (ret == null) {
            return plan;
        } else {
            // 1. create one INDEXSCAN plan node with inlined LIMIT
            // and replace the SEQSCAN node with it
            // 2. we know which end row we want to fetch, so it's safe to
            // specify sorting direction here
            IndexScanPlanNode ispn = new IndexScanPlanNode((SeqScanPlanNode) child, aggplan, ret, sortDirection);
            ispn.setBindings(bindings);
            assert (ispn.getSearchKeyExpressions().size() == 0);
            if (sortDirection == SortDirectionType.ASC) {
                assert (aggplan.isTableMin());
                ispn.setSkipNullPredicate(0);
            }
            LimitPlanNode lpn = new LimitPlanNode();
            lpn.setLimit(1);
            lpn.setOffset(0);
            ispn.addInlinePlanNode(lpn);
            // remove old SeqScan node and link the new generated IndexScan node
            plan.clearChildren();
            plan.addAndLinkChild(ispn);
            return plan;
        }
    }
    if ((child instanceof IndexScanPlanNode) == false) {
        return plan;
    }
    // already have the IndexScanPlanNode
    IndexScanPlanNode ispn = (IndexScanPlanNode) child;
    // we added for reverse scan purpose only
    if (((IndexScanPlanNode) child).getPredicate() != null && !((IndexScanPlanNode) child).isPredicatesOptimizableForAggregate()) {
        return plan;
    }
    // Guard against (possible future?) cases of indexable subquery.
    if (((AbstractScanPlanNode) child).isSubQuery()) {
        return plan;
    }
    // 2. Handle equality filters and one other comparison operator (<, <=, >, >=), see comments below
    if (ispn.getLookupType() != IndexLookupType.EQ && Math.abs(ispn.getSearchKeyExpressions().size() - ExpressionUtil.uncombinePredicate(ispn.getEndExpression()).size()) > 1) {
        return plan;
    }
    // exprs will be used as filterExprs to check the index
    // For forward scan, the initial value is endExprs and might be changed in different values in variant cases
    // For reverse scan, the initial value is initialExprs which is the "old" endExprs
    List<AbstractExpression> exprs;
    int numOfSearchKeys = ispn.getSearchKeyExpressions().size();
    if (ispn.getLookupType() == IndexLookupType.LT || ispn.getLookupType() == IndexLookupType.LTE) {
        exprs = ExpressionUtil.uncombinePredicate(ispn.getInitialExpression());
        numOfSearchKeys -= 1;
    } else {
        exprs = ExpressionUtil.uncombinePredicate(ispn.getEndExpression());
    }
    int numberOfExprs = exprs.size();
    /* Retrieve the index expressions from the target index. (ENG-8819, Ethan)
         * This is because we found that for the following two queries:
         *     #1: explain select max(c2/2) from t where c1=1 and c2/2<=3;
         *     #2: explain select max(c2/2) from t where c1=1 and c2/2<=?;
         * We can get an inline limit 1 for #2 but not for #1. This is because all constants in #1 got parameterized.
         * The result is that the query cannot pass the bindingToIndexedExpression() tests below
         * because we lost all the constant value expressions (cannot attempt to bind a pve to a pve!).
         * Those constant values expressions can only be accessed from the idnex.
         * We will not add those bindings to the ispn.getBindings() here because they will be added anyway in checkIndex().
         * PS: For this case (i.e. index on expressions), checkIndex() will call checkExpressionIndex(),
         * where bindings will be added.
         */
    Index indexToUse = ispn.getCatalogIndex();
    String tableAlias = ispn.getTargetTableAlias();
    List<AbstractExpression> indexedExprs = null;
    if (!indexToUse.getExpressionsjson().isEmpty()) {
        StmtTableScan tableScan = m_parsedStmt.getStmtTableScanByAlias(tableAlias);
        try {
            indexedExprs = AbstractExpression.fromJSONArrayString(indexToUse.getExpressionsjson(), tableScan);
        } catch (JSONException e) {
            e.printStackTrace();
            assert (false);
            return plan;
        }
    }
    /* If there is only 1 difference between searchkeyExprs and endExprs,
         * 1. trivial filters can be discarded, 2 possibilities:
         *      a. SELECT MIN(X) FROM T WHERE [other prefix filters] X < / <= ?
         *         <=> SELECT MIN(X) FROM T WHERE [other prefix filters] && the X < / <= ? filter
         *      b. SELECT MAX(X) FROM T WHERE X > / >= ?
         *         <=> SELECT MAX(X) FROM T with post-filter
         * 2. filter should act as equality filter, 2 possibilities
         *      SELECT MIN(X) FROM T WHERE [other prefix filters] X > / >= ?
         *      SELECT MAX(X) FROM T WHERE [other prefix filters] X < / <= ?

         * check if there is other filters for SELECT MAX(X) FROM T WHERE [other prefix filter AND ] X > / >= ?
         * but we should allow SELECT MAX(X) FROM T WHERE X = ?

         * This is for queries having MAX() but no ORDER BY. (ENG-8819, Ethan)
         * sortDirection == DESC if max, ASC if min. ispn.getSortDirection() == INVALID if no ORDER BY. */
    if (sortDirection == SortDirectionType.DESC && ispn.getSortDirection() == SortDirectionType.INVALID) {
        /* numberOfExprs = exprs.size(), exprs are initial expressions for reversed index scans (lookupType LT, LTE),
             * are end expressions for forward index scans (lookupType GT, GTE, EQ).
             * Note, lookupType doesn't decide the scan direction for sure. MIN(X) where X < ? is still a forward scan.
             * X < ? will be a post filter for the scan rather than an initial expression. */
        if (numberOfExprs == 1) {
            // e.g.: explain select max(c2/2) from t where c2/2<=3;
            // In this case, as long as the where condition (exprs.get(0)) matches the aggregation argument, continue.
            AbstractExpression exprToBind = indexedExprs == null ? exprs.get(0).getLeft() : indexedExprs.get(0);
            if (aggExpr.bindingToIndexedExpression(exprToBind) == null) {
                return plan;
            }
        } else if (numberOfExprs > 1) {
            // ENG-4016: Optimization for query SELECT MAX(X) FROM T WHERE [other prefix filters] X < / <= ?
            // Just keep trying, don't return early.
            boolean earlyReturn = true;
            for (int i = 0; i < numberOfExprs; ++i) {
                AbstractExpression expr = exprs.get(i);
                AbstractExpression indexedExpr = indexedExprs == null ? expr.getLeft() : indexedExprs.get(i);
                if (aggExpr.bindingToIndexedExpression(indexedExpr) != null && (expr.getExpressionType() == ExpressionType.COMPARE_LESSTHANOREQUALTO || expr.getExpressionType() == ExpressionType.COMPARE_LESSTHAN || expr.getExpressionType() == ExpressionType.COMPARE_EQUAL)) {
                    earlyReturn = false;
                    break;
                }
            }
            if (earlyReturn) {
                return plan;
            }
        }
    }
    // have an upper bound: # of endingExpr is more than # of searchExpr
    if (numberOfExprs > numOfSearchKeys) {
        AbstractExpression lastEndExpr = exprs.get(numberOfExprs - 1);
        // check last ending condition, see whether it is
        //      SELECT MIN(X) FROM T WHERE [other prefix filters] X < / <= ? or
        // other filters will be checked later
        AbstractExpression exprToBind = indexedExprs == null ? lastEndExpr.getLeft() : indexedExprs.get(numberOfExprs - 1);
        if ((lastEndExpr.getExpressionType() == ExpressionType.COMPARE_LESSTHAN || lastEndExpr.getExpressionType() == ExpressionType.COMPARE_LESSTHANOREQUALTO) && aggExpr.bindingToIndexedExpression(exprToBind) != null) {
            exprs.remove(lastEndExpr);
        }
    }
    // and we can take advantage of that
    if (checkIndex(ispn.getCatalogIndex(), aggExpr, exprs, ispn.getBindings(), tableAlias)) {
        // we know which end we want to fetch, set the sort direction
        ispn.setSortDirection(sortDirection);
        // for SELECT MIN(X) FROM T WHERE [prefix filters] = ?
        if (numberOfExprs == numOfSearchKeys && sortDirection == SortDirectionType.ASC) {
            if (ispn.getLookupType() == IndexLookupType.GTE) {
                assert (aggplan.isTableMin());
                ispn.setSkipNullPredicate(numOfSearchKeys);
            }
        }
        // reset the IndexLookupType, remove "added" searchKey, add back to endExpression, and clear "added" predicate
        if (sortDirection == SortDirectionType.ASC && (ispn.getLookupType() == IndexLookupType.LT || ispn.getLookupType() == IndexLookupType.LTE)) {
            ispn.setLookupType(IndexLookupType.GTE);
            ispn.removeLastSearchKey();
            ispn.addEndExpression(ExpressionUtil.uncombinePredicate(ispn.getInitialExpression()).get(numberOfExprs - 1));
            ispn.setSkipNullPredicate(numOfSearchKeys);
            ispn.resetPredicate();
        }
        // add an inline LIMIT plan node to this index scan plan node
        LimitPlanNode lpn = new LimitPlanNode();
        lpn.setLimit(1);
        lpn.setOffset(0);
        ispn.addInlinePlanNode(lpn);
        //                                              |__LimitPlanNode
        if (sortDirection == SortDirectionType.DESC && !ispn.getSearchKeyExpressions().isEmpty() && exprs.isEmpty() && ExpressionUtil.uncombinePredicate(ispn.getInitialExpression()).isEmpty()) {
            AbstractExpression newPredicate = new ComparisonExpression();
            if (ispn.getLookupType() == IndexLookupType.GT)
                newPredicate.setExpressionType(ExpressionType.COMPARE_GREATERTHAN);
            if (ispn.getLookupType() == IndexLookupType.GTE)
                newPredicate.setExpressionType(ExpressionType.COMPARE_GREATERTHANOREQUALTO);
            newPredicate.setRight(ispn.getSearchKeyExpressions().get(0));
            newPredicate.setLeft(aggExpr);
            newPredicate.setValueType(aggExpr.getValueType());
            ispn.clearSearchKeyExpression();
            aggplan.setPrePredicate(newPredicate);
        }
    }
    return plan;
}

Example 2 with AbstractScanPlanNode

use of org.voltdb.plannodes.AbstractScanPlanNode in project voltdb by VoltDB.

the class InlineOrderByIntoMergeReceive method applyOptimization.

/**
     * For MP queries, the coordinator's OrderBy node can be replaced with
     * a specialized Receive node that merges individual partitions results
     * into a final result set if the partitions result set is sorted
     * in the order matching the ORDER BY order
     *
     * @param orderbyNode - ORDER BY node to optimize
     * @return optimized plan
     */
AbstractPlanNode applyOptimization(OrderByPlanNode orderbyNode) {
    // Find all child RECEIVE nodes. We are not interested in the MERGERECEIVE nodes there
    // because they could only come from subqueries.
    List<AbstractPlanNode> receives = orderbyNode.findAllNodesOfType(PlanNodeType.RECEIVE);
    if (receives.isEmpty()) {
        return orderbyNode;
    }
    assert (receives.size() == 1);
    ReceivePlanNode receive = (ReceivePlanNode) receives.get(0);
    // Make sure that this receive node belongs to the same coordinator fragment that
    // the ORDER BY node does. Alternatively, it could belong to a distributed subquery.
    // Walk up the tree starting at the receive node until we hit either a scan node
    // (distributed subquery) or the original order by node (distributed order by)
    // Collect all nodes that are currently in between ORDER BY and RECEIVE nodes
    // If the optimization is possible, they will be converted to inline nodes of
    // the MERGE RECEIVE node. The expected node types are:
    //      LIMIT, AGGREGATE/PARTIALAGGREGATE/HASHAGGREGATE
    // The HASHAGGREGATE must be convertible to AGGREGATE or PARTIALAGGREGATE for optimization
    // to be applicable.
    // LIMIT can be already inline with ORDER BY node
    AbstractPlanNode limitNode = orderbyNode.getInlinePlanNode(PlanNodeType.LIMIT);
    AbstractPlanNode aggregateNode = null;
    AbstractPlanNode inlineCandidate = receive.getParent(0);
    while (orderbyNode != inlineCandidate) {
        if (inlineCandidate instanceof AbstractScanPlanNode) {
            // it's a subquery
            return orderbyNode;
        }
        PlanNodeType nodeType = inlineCandidate.getPlanNodeType();
        if (nodeType == PlanNodeType.LIMIT && limitNode == null) {
            limitNode = inlineCandidate;
        } else if ((nodeType == PlanNodeType.AGGREGATE || nodeType == PlanNodeType.PARTIALAGGREGATE) && aggregateNode == null) {
            aggregateNode = inlineCandidate;
        } else if (nodeType == PlanNodeType.HASHAGGREGATE && aggregateNode == null) {
            aggregateNode = convertToSerialAggregation(inlineCandidate, orderbyNode);
            if (PlanNodeType.HASHAGGREGATE == aggregateNode.getPlanNodeType()) {
                return orderbyNode;
            }
        } else {
            // Don't know how to handle this node or there is already a node of this type
            return orderbyNode;
        }
        // move up one node
        assert (inlineCandidate.getParentCount() == 1);
        inlineCandidate = inlineCandidate.getParent(0);
    }
    assert (receive.getChildCount() == 1);
    AbstractPlanNode partitionRoot = receive.getChild(0);
    if (!partitionRoot.isOutputOrdered(orderbyNode.getSortExpressions(), orderbyNode.getSortDirections())) {
        // Partition results are not ordered
        return orderbyNode;
    }
    // the new MERGERECIEVE node.. All in-between nodes will be inlined
    assert (orderbyNode.getParentCount() <= 1);
    AbstractPlanNode rootNode = (orderbyNode.getParentCount() == 1) ? orderbyNode.getParent(0) : null;
    MergeReceivePlanNode mergeReceive = new MergeReceivePlanNode();
    assert (receive.getChildCount() == 1);
    mergeReceive.addAndLinkChild(receive.getChild(0));
    receive.removeFromGraph();
    if (rootNode == null) {
        rootNode = mergeReceive;
    } else {
        rootNode.clearChildren();
        rootNode.addAndLinkChild(mergeReceive);
    }
    // Add inline ORDER BY node and remove inline LIMIT node if any
    mergeReceive.addInlinePlanNode(orderbyNode);
    if (limitNode != null) {
        orderbyNode.removeInlinePlanNode(PlanNodeType.LIMIT);
    }
    // Add inline aggregate
    if (aggregateNode != null) {
        if (limitNode != null) {
            // Inline LIMIT with aggregate
            aggregateNode.addInlinePlanNode(limitNode);
        }
        mergeReceive.addInlinePlanNode(aggregateNode);
    }
    // Add LIMIT if it is exist and wasn't inline with aggregate node
    if (limitNode != null && aggregateNode == null) {
        mergeReceive.addInlinePlanNode(limitNode);
    }
    // return the new root
    return rootNode;
}

Example 3 with AbstractScanPlanNode

use of org.voltdb.plannodes.AbstractScanPlanNode in project voltdb by VoltDB.

the class PushdownLimits method recursivelyApply.

@Override
protected AbstractPlanNode recursivelyApply(AbstractPlanNode plan) {
    assert (plan != null);
    // depth first:
    //     find LimitPlanNodes with exactly one child
    //     where that child is an AbstractScanPlanNode
    //     disconnect the LimitPlanNode
    //     and inline the LimitPlanNode in to the AbstractScanPlanNode
    ArrayList<AbstractPlanNode> children = new ArrayList<AbstractPlanNode>();
    for (int i = 0; i < plan.getChildCount(); i++) children.add(plan.getChild(i));
    plan.clearChildren();
    for (AbstractPlanNode child : children) {
        // TODO this will break when children feed multiple parents
        child = recursivelyApply(child);
        child.clearParents();
        plan.addAndLinkChild(child);
    }
    if (!(plan instanceof LimitPlanNode)) {
        return plan;
    }
    if (plan.getChildCount() != 1) {
        assert (plan.getChildCount() == 1);
        return plan;
    }
    AbstractPlanNode child = plan.getChild(0);
    // push into Scans
    if (child instanceof AbstractScanPlanNode) {
        // in future, this limit can be aggregate inline node.
        if (AggregatePlanNode.getInlineAggregationNode(child) != null) {
            return plan;
        }
        plan.clearChildren();
        child.clearParents();
        child.addInlinePlanNode(plan);
        return child;
    }
    // == child/projection . recursivelyApply(plan/limit . leaf/whatever)
    if (child instanceof ProjectionPlanNode) {
        assert (child.getChildCount() == 1);
        AbstractPlanNode leaf = child.getChild(0);
        leaf.clearParents();
        plan.clearChildren();
        plan.addAndLinkChild(leaf);
        child.clearChildren();
        child.clearParents();
        child.addAndLinkChild(plan);
        return recursivelyApply(child);
    }
    // push into JOINs
    if (child instanceof AbstractJoinPlanNode) {
        plan.clearChildren();
        child.clearParents();
        child.addInlinePlanNode(plan);
        // }
        return child;
    }
    return plan;
}

Example 4 with AbstractScanPlanNode

use of org.voltdb.plannodes.AbstractScanPlanNode in project voltdb by VoltDB.

the class TestPlansGroupBy method testDistinctA1_Subquery.

public void testDistinctA1_Subquery() {
    AbstractPlanNode p;
    List<AbstractPlanNode> pns;
    // Distinct rewrote with group by
    pns = compileToFragments("select * from (SELECT DISTINCT A1 FROM T1) temp");
    p = pns.get(0).getChild(0);
    assertTrue(p instanceof SeqScanPlanNode);
    assertTrue(p.getChild(0) instanceof HashAggregatePlanNode);
    assertTrue(p.getChild(0).getChild(0) instanceof ReceivePlanNode);
    p = pns.get(1).getChild(0);
    assertTrue(p instanceof AbstractScanPlanNode);
    assertNotNull(p.getInlinePlanNode(PlanNodeType.HASHAGGREGATE));
}

Example 5 with AbstractScanPlanNode

use of org.voltdb.plannodes.AbstractScanPlanNode in project voltdb by VoltDB.

the class TestPlansGroupBy method testComplexGroupBy.

public void testComplexGroupBy() {
    List<AbstractPlanNode> pns;
    pns = compileToFragments("SELECT A1, ABS(A1), ABS(A1)+1, sum(B1) FROM P1 GROUP BY A1, ABS(A1)");
    checkHasComplexAgg(pns);
    // Check it can compile
    pns = compileToFragments("SELECT ABS(A1), sum(B1) FROM P1 GROUP BY ABS(A1)");
    AbstractPlanNode p = pns.get(0).getChild(0);
    assertTrue(p instanceof AggregatePlanNode);
    p = pns.get(1).getChild(0);
    // inline aggregate
    assertTrue(p instanceof AbstractScanPlanNode);
    assertNotNull(p.getInlinePlanNode(PlanNodeType.HASHAGGREGATE));
    pns = compileToFragments("SELECT A1+PKEY, avg(B1) as tag FROM P1 GROUP BY A1+PKEY ORDER BY ABS(tag), A1+PKEY");
    checkHasComplexAgg(pns);
}