Ejemplo n.º 1
0
    // static
    bool QueryPlannerIXSelect::compatible(const BSONElement& elt,
                                          const IndexEntry& index,
                                          MatchExpression* node) {
        // Historically one could create indices with any particular value for the index spec,
        // including values that now indicate a special index.  As such we have to make sure the
        // index type wasn't overridden before we pay attention to the string in the index key
        // pattern element.
        //
        // e.g. long ago we could have created an index {a: "2dsphere"} and it would
        // be treated as a btree index by an ancient version of MongoDB.  To try to run
        // 2dsphere queries over it would be folly.
        string indexedFieldType;
        if (String != elt.type() || (INDEX_BTREE == index.type)) {
            indexedFieldType = "";
        }
        else {
            indexedFieldType = elt.String();
        }

        // We know elt.fieldname() == node->path().
        MatchExpression::MatchType exprtype = node->matchType();

        if (indexedFieldType.empty()) {
            // Can't check for null w/a sparse index.
            if (exprtype == MatchExpression::EQ && index.sparse) {
                const EqualityMatchExpression* expr
                    = static_cast<const EqualityMatchExpression*>(node);
                if (expr->getData().isNull()) {
                    return false;
                }
            }

            // We can't use a btree-indexed field for geo expressions.
            if (exprtype == MatchExpression::GEO || exprtype == MatchExpression::GEO_NEAR) {
                return false;
            }

            // There are restrictions on when we can use the index if
            // the expression is a NOT.
            if (exprtype == MatchExpression::NOT) {
                // Prevent negated preds from using sparse or
                // multikey indices. We do so for sparse indices because
                // we will fail to return the documents which do not contain
                // the indexed fields.
                //
                // We avoid multikey indices because of the semantics of
                // negations on multikey fields. For example, with multikey
                // index {a:1}, the document {a: [1,2,3]} does *not* match
                // the query {a: {$ne: 3}}. We'd mess this up if we used
                // an index scan over [MinKey, 3) and (3, MaxKey] without
                // a filter.
                if (index.sparse || index.multikey) {
                    return false;
                }
                // Can't index negations of MOD or REGEX
                MatchExpression::MatchType childtype = node->getChild(0)->matchType();
                if (MatchExpression::REGEX == childtype ||
                    MatchExpression::MOD == childtype) {
                    return false;
                }
            }

            // We can only index EQ using text indices.  This is an artificial limitation imposed by
            // FTSSpec::getIndexPrefix() which will fail if there is not an EQ predicate on each
            // index prefix field of the text index.
            //
            // Example for key pattern {a: 1, b: "text"}:
            // - Allowed: node = {a: 7}
            // - Not allowed: node = {a: {$gt: 7}}

            if (INDEX_TEXT != index.type) {
                return true;
            }

            // If we're here we know it's a text index.  Equalities are OK anywhere in a text index.
            if (MatchExpression::EQ == exprtype) {
                return true;
            }

            // Not-equalities can only go in a suffix field of an index kp.  We look through the key
            // pattern to see if the field we're looking at now appears as a prefix.  If so, we
            // can't use this index for it.
            BSONObjIterator specIt(index.keyPattern);
            while (specIt.more()) {
                BSONElement elt = specIt.next();
                // We hit the dividing mark between prefix and suffix, so whatever field we're
                // looking at is a suffix, since it appears *after* the dividing mark between the
                // two.  As such, we can use the index.
                if (String == elt.type()) {
                    return true;
                }

                // If we're here, we're still looking at prefix elements.  We know that exprtype
                // isn't EQ so we can't use this index.
                if (node->path() == elt.fieldNameStringData()) {
                    return false;
                }
            }

            // NOTE: This shouldn't be reached.  Text index implies there is a separator implies we
            // will always hit the 'return true' above.
            invariant(0);
            return true;
        }
        else if (IndexNames::HASHED == indexedFieldType) {
            return exprtype == MatchExpression::MATCH_IN || exprtype == MatchExpression::EQ;
        }
        else if (IndexNames::GEO_2DSPHERE == indexedFieldType) {
            if (exprtype == MatchExpression::GEO) {
                // within or intersect.
                GeoMatchExpression* gme = static_cast<GeoMatchExpression*>(node);
                const GeoQuery& gq = gme->getGeoQuery();
                const GeometryContainer& gc = gq.getGeometry();
                return gc.hasS2Region();
            }
            else if (exprtype == MatchExpression::GEO_NEAR) {
                GeoNearMatchExpression* gnme = static_cast<GeoNearMatchExpression*>(node);
                // Make sure the near query is compatible with 2dsphere.
                if (gnme->getData().centroid.crs == SPHERE || gnme->getData().isNearSphere) {
                    return true;
                }
            }
            return false;
        }
        else if (IndexNames::GEO_2D == indexedFieldType) {
            if (exprtype == MatchExpression::GEO_NEAR) {
                GeoNearMatchExpression* gnme = static_cast<GeoNearMatchExpression*>(node);
                return gnme->getData().centroid.crs == FLAT;
            }
            else if (exprtype == MatchExpression::GEO) {
                // 2d only supports within.
                GeoMatchExpression* gme = static_cast<GeoMatchExpression*>(node);
                const GeoQuery& gq = gme->getGeoQuery();
                if (GeoQuery::WITHIN != gq.getPred()) {
                    return false;
                }

                const GeometryContainer& gc = gq.getGeometry();

                // 2d indices answer flat queries.
                if (gc.hasFlatRegion()) {
                    return true;
                }

                // 2d indices can answer centerSphere queries.
                if (NULL == gc._cap.get()) {
                    return false;
                }

                verify(SPHERE == gc._cap->crs);
                const Circle& circle = gc._cap->circle;

                // No wrapping around the edge of the world is allowed in 2d centerSphere.
                return twoDWontWrap(circle, index);
            }
            return false;
        }
        else if (IndexNames::TEXT == indexedFieldType) {
            return (exprtype == MatchExpression::TEXT);
        }
        else if (IndexNames::GEO_HAYSTACK == indexedFieldType) {
            return false;
        }
        else {
            warning() << "Unknown indexing for node " << node->toString()
                      << " and field " << elt.toString() << endl;
            verify(0);
        }
    }
Ejemplo n.º 2
0
    // static
    bool QueryPlannerIXSelect::compatible(const BSONElement& elt,
                                          const IndexEntry& index,
                                          MatchExpression* node) {
        // XXX: CatalogHack::getAccessMethodName: do we have to worry about this?  when?
        string ixtype;
        if (String != elt.type()) {
            ixtype = "";
        }
        else {
            ixtype = elt.String();
        }

        // We know elt.fieldname() == node->path().
        MatchExpression::MatchType exprtype = node->matchType();

        // TODO: use indexnames
        if ("" == ixtype) {
            if (index.sparse && exprtype == MatchExpression::EQ) {
                // Can't check for null w/a sparse index.
                const EqualityMatchExpression* expr
                    = static_cast<const EqualityMatchExpression*>(node);
                return !expr->getData().isNull();
            }
            return exprtype != MatchExpression::GEO && exprtype != MatchExpression::GEO_NEAR;
        }
        else if ("hashed" == ixtype) {
            return exprtype == MatchExpression::MATCH_IN || exprtype == MatchExpression::EQ;
        }
        else if ("2dsphere" == ixtype) {
            if (exprtype == MatchExpression::GEO) {
                // within or intersect.
                GeoMatchExpression* gme = static_cast<GeoMatchExpression*>(node);
                const GeoQuery& gq = gme->getGeoQuery();
                const GeometryContainer& gc = gq.getGeometry();
                return gc.hasS2Region();
            }
            else if (exprtype == MatchExpression::GEO_NEAR) {
                GeoNearMatchExpression* gnme = static_cast<GeoNearMatchExpression*>(node);
                // Make sure the near query is compatible with 2dsphere.
                if (gnme->getData().centroid.crs == SPHERE || gnme->getData().isNearSphere) {
                    return true;
                }
            }
            return false;
        }
        else if ("2d" == ixtype) {
            if (exprtype == MatchExpression::GEO_NEAR) {
                GeoNearMatchExpression* gnme = static_cast<GeoNearMatchExpression*>(node);
                return gnme->getData().centroid.crs == FLAT;
            }
            else if (exprtype == MatchExpression::GEO) {
                // 2d only supports within.
                GeoMatchExpression* gme = static_cast<GeoMatchExpression*>(node);
                const GeoQuery& gq = gme->getGeoQuery();
                if (GeoQuery::WITHIN != gq.getPred()) {
                    return false;
                }

                const GeometryContainer& gc = gq.getGeometry();

                // 2d indices answer flat queries.
                if (gc.hasFlatRegion()) {
                    return true;
                }

                // 2d indices can answer centerSphere queries.
                if (NULL == gc._cap.get()) {
                    return false;
                }

                verify(SPHERE == gc._cap->crs);
                const Circle& circle = gc._cap->circle;

                // No wrapping around the edge of the world is allowed in 2d centerSphere.
                return twoDWontWrap(circle, index);
            }
            return false;
        }
        else if ("text" == ixtype) {
            return (exprtype == MatchExpression::TEXT);
        }
        else if ("geoHaystack" == ixtype) {
            return false;
        }
        else {
            warning() << "Unknown indexing for node " << node->toString()
                      << " and field " << elt.toString() << endl;
            verify(0);
        }
    }