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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/db/query/expression_index.h"
#include <iostream>
#include <third_party/s2/s2cellid.h>
#include <third_party/s2/s2region.h>
#include <third_party/s2/s2regioncoverer.h>
#include <unordered_set>
#include "mongo/db/geo/geoconstants.h"
#include "mongo/db/geo/r2_region_coverer.h"
#include "mongo/db/hasher.h"
#include "mongo/db/index/expression_params.h"
#include "mongo/db/query/expression_index_knobs_gen.h"
#include "mongo/logv2/log.h"
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kQuery
namespace mongo {
using std::set;
BSONObj ExpressionMapping::hash(const BSONElement& value) {
BSONObjBuilder bob;
bob.append("", BSONElementHasher::hash64(value, BSONElementHasher::DEFAULT_HASH_SEED));
return bob.obj();
}
// For debugging only
static std::string toCoveringString(const GeoHashConverter& hashConverter,
const set<GeoHash>& covering) {
string result = "[";
for (set<GeoHash>::const_iterator it = covering.begin(); it != covering.end(); ++it) {
if (it != covering.begin())
result += ", ";
const GeoHash& geoHash = *it;
result += hashConverter.unhashToBoxCovering(geoHash).toString();
result += " (" + geoHash.toStringHex1() + ")";
}
return result + "]";
}
std::vector<GeoHash> ExpressionMapping::get2dCovering(const R2Region& region,
const BSONObj& indexInfoObj,
int maxCoveringCells) {
auto result = GeoHashConverter::createFromDoc(indexInfoObj);
verify(result.isOK()); // We validated the parameters when creating the index.
const auto bits = result.getValue()->getBits();
R2RegionCoverer coverer(std::move(result.getValue()));
coverer.setMaxLevel(bits);
coverer.setMaxCells(maxCoveringCells);
// TODO: Maybe slightly optimize by returning results in order
std::vector<GeoHash> unorderedCovering;
coverer.getCovering(region, &unorderedCovering);
return unorderedCovering;
}
void ExpressionMapping::GeoHashsToIntervalsWithParents(
const std::vector<GeoHash>& unorderedCovering, OrderedIntervalList* oilOut) {
set<GeoHash> covering(unorderedCovering.begin(), unorderedCovering.end());
for (set<GeoHash>::const_iterator it = covering.begin(); it != covering.end(); ++it) {
const GeoHash& geoHash = *it;
BSONObjBuilder builder;
geoHash.appendHashMin(&builder, "");
geoHash.appendHashMax(&builder, "");
oilOut->intervals.push_back(IndexBoundsBuilder::makeRangeInterval(
builder.obj(), BoundInclusion::kIncludeBothStartAndEndKeys));
}
}
void ExpressionMapping::cover2d(const R2Region& region,
const BSONObj& indexInfoObj,
int maxCoveringCells,
OrderedIntervalList* oilOut) {
std::vector<GeoHash> unorderedCovering = get2dCovering(region, indexInfoObj, maxCoveringCells);
GeoHashsToIntervalsWithParents(unorderedCovering, oilOut);
}
std::vector<S2CellId> ExpressionMapping::get2dsphereCovering(const S2Region& region) {
auto minLevel = gInternalQueryS2GeoCoarsestLevel.load();
auto maxLevel = gInternalQueryS2GeoFinestLevel.load();
uassert(28739, "Geo coarsest level must be in range [0,30]", 0 <= minLevel && minLevel <= 30);
uassert(28740, "Geo finest level must be in range [0,30]", 0 <= maxLevel && maxLevel <= 30);
uassert(28741, "Geo coarsest level must be less than or equal to finest", minLevel <= maxLevel);
S2RegionCoverer coverer;
coverer.set_min_level(minLevel);
coverer.set_max_level(maxLevel);
coverer.set_max_cells(gInternalQueryS2GeoMaxCells.load());
std::vector<S2CellId> cover;
coverer.GetCovering(region, &cover);
return cover;
}
void ExpressionMapping::cover2dsphere(const S2Region& region,
const S2IndexingParams& indexingParams,
OrderedIntervalList* oilOut) {
std::vector<S2CellId> cover = get2dsphereCovering(region);
S2CellIdsToIntervalsWithParents(cover, indexingParams, oilOut);
}
namespace {
bool compareIntervals(const Interval& a, const Interval& b) {
return a.precedes(b);
}
void S2CellIdsToIntervalsUnsorted(const std::vector<S2CellId>& intervalSet,
const S2IndexVersion indexVersion,
OrderedIntervalList* oilOut) {
for (const S2CellId& interval : intervalSet) {
BSONObjBuilder b;
if (indexVersion >= S2_INDEX_VERSION_3) {
long long start = static_cast<long long>(interval.range_min().id());
long long end = static_cast<long long>(interval.range_max().id());
b.append("start", start);
b.append("end", end);
invariant(start <= end);
oilOut->intervals.push_back(IndexBoundsBuilder::makeRangeInterval(
b.obj(), BoundInclusion::kIncludeBothStartAndEndKeys));
} else {
// for backwards compatibility, use strings
std::string start = interval.toString();
std::string end = start;
end[start.size() - 1]++;
b.append("start", start);
b.append("end", end);
oilOut->intervals.push_back(IndexBoundsBuilder::makeRangeInterval(
b.obj(), BoundInclusion::kIncludeStartKeyOnly));
}
}
}
} // namespace
void ExpressionMapping::S2CellIdsToIntervals(const std::vector<S2CellId>& intervalSet,
const S2IndexVersion indexVersion,
OrderedIntervalList* oilOut) {
// Order is not preserved in changing from numeric to string
// form of index key. Therefore, sorting is deferred to after
// intervals are made
S2CellIdsToIntervalsUnsorted(intervalSet, indexVersion, oilOut);
std::sort(oilOut->intervals.begin(), oilOut->intervals.end(), compareIntervals);
// Make sure that our intervals don't overlap each other and are ordered correctly.
// This perhaps should only be done in debug mode.
if (!oilOut->isValidFor(1)) {
LOGV2(6029801,
"invalid OrderedIntervalList",
"orderedIntervalList"_attr = oilOut->toString(false));
MONGO_UNREACHABLE;
}
}
void ExpressionMapping::S2CellIdsToIntervalsWithParents(const std::vector<S2CellId>& intervalSet,
const S2IndexingParams& indexParams,
OrderedIntervalList* oilOut) {
// There may be duplicates when going up parent cells if two cells share a parent
std::unordered_set<S2CellId> exactSet; // NOLINT
for (const S2CellId& interval : intervalSet) {
S2CellId coveredCell = interval;
// Look at the cells that cover us. We want to look at every cell that contains the
// covering we would index on if we were to insert the query geometry. We generate
// the would-index-with-this-covering and find all the cells strictly containing the
// cells in that set, until we hit the coarsest indexed cell. We use equality, not
// a prefix match. Why not prefix? Because we've already looked at everything
// finer or as fine as our initial covering.
//
// Say we have a fine point with cell id 212121, we go up one, get 21212, we don't
// want to look at cells 21212[not-1] because we know they're not going to intersect
// with 212121, but entries inserted with cell value 21212 (no trailing digits) may.
// And we've already looked at points with the cell id 211111 from the regex search
// created above, so we only want things where the value of the last digit is not
// stored (and therefore could be 1).
while (coveredCell.level() > indexParams.coarsestIndexedLevel) {
// Add the parent cell of the currently covered cell since we aren't at the
// coarsest level yet
// NOTE: Be careful not to generate cells strictly less than the
// coarsestIndexedLevel - this can result in S2 failures when level < 0.
coveredCell = coveredCell.parent();
exactSet.insert(coveredCell);
}
}
for (const S2CellId& exact : exactSet) {
BSONObj exactBSON = S2CellIdToIndexKey(exact, indexParams.indexVersion);
oilOut->intervals.push_back(IndexBoundsBuilder::makePointInterval(exactBSON));
}
S2CellIdsToIntervalsUnsorted(intervalSet, indexParams.indexVersion, oilOut);
std::sort(oilOut->intervals.begin(), oilOut->intervals.end(), compareIntervals);
// Make sure that our intervals don't overlap each other and are ordered correctly.
// This perhaps should only be done in debug mode.
if (!oilOut->isValidFor(1)) {
LOGV2(6029802,
"invalid OrderedIntervalList",
"orderedIntervalList"_attr = oilOut->toString(false));
MONGO_UNREACHABLE;
}
}
} // namespace mongo
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