Examples with NestedLoopJoin io.crate.planner.operators.NestedLoopJoin used on opensource projects

Example 1 with NestedLoopJoin

use of io.crate.planner.operators.NestedLoopJoin in project crate by crate.

the class RewriteFilterOnOuterJoinToInnerJoin method apply.

@Override
public LogicalPlan apply(Filter filter, Captures captures, TableStats tableStats, TransactionContext txnCtx, NodeContext nodeCtx) {
    var symbolEvaluator = new SymbolEvaluator(txnCtx, nodeCtx, SubQueryResults.EMPTY);
    NestedLoopJoin nl = captures.get(nlCapture);
    Symbol query = filter.query();
    Map<Set<RelationName>, Symbol> splitQueries = QuerySplitter.split(query);
    if (splitQueries.size() == 1 && splitQueries.keySet().iterator().next().size() > 1) {
        return null;
    }
    LogicalPlan lhs = nl.sources().get(0);
    LogicalPlan rhs = nl.sources().get(1);
    Set<RelationName> leftName = lhs.getRelationNames();
    Set<RelationName> rightName = rhs.getRelationNames();
    Symbol leftQuery = splitQueries.remove(leftName);
    Symbol rightQuery = splitQueries.remove(rightName);
    final LogicalPlan newLhs;
    final LogicalPlan newRhs;
    final boolean newJoinIsInnerJoin;
    switch(nl.joinType()) {
        case LEFT:
            /* LEFT OUTER JOIN -> NULL rows are generated for the RHS if the join-condition doesn't match
                 *
                 * cr> select t1.x as t1x, t2.x as t2x from t1 left join t2 on t1.x = t2.x;
                 * +-----+------+
                 * | t1x |  t2x |
                 * +-----+------+
                 * |   3 |    3 |
                 * |   2 |    2 |
                 * |   1 | NULL |
                 * +-----+------+
                 */
            newLhs = getNewSource(leftQuery, lhs);
            if (rightQuery == null) {
                newRhs = rhs;
                newJoinIsInnerJoin = false;
            } else if (couldMatchOnNull(rightQuery, symbolEvaluator)) {
                newRhs = rhs;
                newJoinIsInnerJoin = false;
                splitQueries.put(rightName, rightQuery);
            } else {
                newRhs = getNewSource(rightQuery, rhs);
                newJoinIsInnerJoin = true;
            }
            break;
        case RIGHT:
            /* RIGHT OUTER JOIN -> NULL rows are generated for the LHS if the join-condition doesn't match

                 * cr> select t1.x as t1x, t2.x as t2x from t1 right join t2 on t1.x = t2.x;
                 * +------+-----+
                 * |  t1x | t2x |
                 * +------+-----+
                 * |    3 |   3 |
                 * |    2 |   2 |
                 * | NULL |   4 |
                 * +------+-----+
                 */
            if (leftQuery == null) {
                newLhs = lhs;
                newJoinIsInnerJoin = false;
            } else if (couldMatchOnNull(leftQuery, symbolEvaluator)) {
                newLhs = lhs;
                newJoinIsInnerJoin = false;
                splitQueries.put(leftName, leftQuery);
            } else {
                newLhs = getNewSource(leftQuery, lhs);
                newJoinIsInnerJoin = true;
            }
            newRhs = getNewSource(rightQuery, rhs);
            break;
        case FULL:
            if (couldMatchOnNull(leftQuery, symbolEvaluator)) {
                newLhs = lhs;
            } else {
                newLhs = getNewSource(leftQuery, lhs);
                if (leftQuery != null) {
                    splitQueries.put(leftName, leftQuery);
                }
            }
            if (couldMatchOnNull(rightQuery, symbolEvaluator)) {
                newRhs = rhs;
            } else {
                newRhs = getNewSource(rightQuery, rhs);
            }
            /*
                 * Filters on each side must be put back into the Filter as each side can generate NULL's on outer joins
                 * which must be filtered out AFTER the join operation.
                 * In case the filter is only on one side, the join could be rewritten to a LEFT/RIGHT OUTER.
                 * TODO: Create a dedicated rule RewriteFilterOnOuterJoinToLeftOrRight
                 *
                 * cr> select t1.x as t1x, t2.x as t2x, t2.y as t2y from t1 full outer join t2 on t1.x = t2.x where t2y = 1;
                 * +------+------+------+
                 * |  t1x |  t2x |  t2y |
                 * +------+------+------+
                 * |    3 |    3 |    1 |
                 * |    2 |    2 |    1 |
                 * | NULL |    4 |    1 |
                 * +------+------+------+
                 */
            if (leftQuery != null) {
                splitQueries.put(leftName, leftQuery);
            }
            if (rightQuery != null) {
                splitQueries.put(rightName, rightQuery);
            }
            newJoinIsInnerJoin = newLhs != lhs && newRhs != rhs;
            break;
        default:
            throw new UnsupportedOperationException("The Rule to rewrite filter+outer-joins to inner joins must not be run on joins of type=" + nl.joinType());
    }
    if (newLhs == lhs && newRhs == rhs) {
        return null;
    }
    NestedLoopJoin newJoin = new NestedLoopJoin(newLhs, newRhs, newJoinIsInnerJoin ? JoinType.INNER : nl.joinType(), nl.joinCondition(), nl.isFiltered(), nl.topMostLeftRelation(), nl.orderByWasPushedDown(), true);
    assert newJoin.outputs().equals(nl.outputs()) : "Outputs after rewrite must be the same as before";
    return splitQueries.isEmpty() ? newJoin : new Filter(newJoin, AndOperator.join(splitQueries.values()));
}

Example 2 with NestedLoopJoin

use of io.crate.planner.operators.NestedLoopJoin in project crate by crate.

the class MoveOrderBeneathNestedLoop method apply.

@Override
public LogicalPlan apply(Order order, Captures captures, TableStats tableStats, TransactionContext txnCtx, NodeContext nodeCtx) {
    NestedLoopJoin nestedLoop = captures.get(nlCapture);
    Set<RelationName> relationsInOrderBy = Collections.newSetFromMap(new IdentityHashMap<>());
    Consumer<ScopedSymbol> gatherRelationsFromField = f -> relationsInOrderBy.add(f.relation());
    Consumer<Reference> gatherRelationsFromRef = r -> relationsInOrderBy.add(r.ident().tableIdent());
    OrderBy orderBy = order.orderBy();
    for (Symbol orderExpr : orderBy.orderBySymbols()) {
        FieldsVisitor.visitFields(orderExpr, gatherRelationsFromField);
        RefVisitor.visitRefs(orderExpr, gatherRelationsFromRef);
    }
    if (relationsInOrderBy.size() == 1) {
        RelationName relationInOrderBy = relationsInOrderBy.iterator().next();
        if (relationInOrderBy == nestedLoop.topMostLeftRelation().relationName()) {
            LogicalPlan lhs = nestedLoop.sources().get(0);
            LogicalPlan newLhs = order.replaceSources(List.of(lhs));
            return new NestedLoopJoin(newLhs, nestedLoop.sources().get(1), nestedLoop.joinType(), nestedLoop.joinCondition(), nestedLoop.isFiltered(), nestedLoop.topMostLeftRelation(), true, nestedLoop.isRewriteFilterOnOuterJoinToInnerJoinDone());
        }
    }
    return null;
}