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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.
*/
#pragma once
#include <set>
#include <string>
#include "mongo/db/exec/projection_exec_agg.h"
#include "mongo/db/field_ref.h"
#include "mongo/db/index/multikey_paths.h"
#include "mongo/db/index_names.h"
#include "mongo/db/jsobj.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
class CollatorInterface;
class MatchExpression;
/**
* A CoreIndexInfo is a representation of an index in the catalog with parsed information which is
* used for updating indexability discriminators. Its lifetime is not tied to the underlying
* collection. It is a subset of IndexEntry and is missing fields that are expensive or unavailable.
*/
struct CoreIndexInfo {
struct Identifier;
CoreIndexInfo(const BSONObj& kp,
IndexType type,
bool sp,
Identifier ident,
const MatchExpression* fe = nullptr,
const CollatorInterface* ci = nullptr,
const ProjectionExecAgg* projExec = nullptr)
: identifier(std::move(ident)),
keyPattern(kp),
filterExpr(fe),
type(type),
sparse(sp),
collator(ci),
wildcardProjection(projExec) {
// We always expect a projection executor for $** indexes, and none otherwise.
invariant((type == IndexType::INDEX_WILDCARD) == (projExec != nullptr));
}
/**
* This struct is used to uniquely identify an index. The index "Identifier" has two
* components: catalog name, and "disambiguator". The catalog name is just the name of the
* index in the catalog. The disambiguator is used by the planner when multiple IndexEntries
* may refer to the same underlying index in the catalog. This can only happen with $**
* indices. Otherwise, the disambiguator should be empty.
*
* Has the same comparison and equality semantics as std::pair<string, string>.
*
*/
struct Identifier {
explicit Identifier(std::string aCatalogName) : catalogName(std::move(aCatalogName)) {}
Identifier(std::string aCatalogName, std::string nameDisambiguator)
: catalogName(std::move(aCatalogName)), disambiguator(std::move(nameDisambiguator)) {}
bool operator==(const Identifier& other) const {
return other.catalogName == catalogName && other.disambiguator == disambiguator;
}
bool operator!=(const Identifier& other) const {
return !(*this == other);
}
bool operator<(const Identifier& other) const {
const auto cmpRes = catalogName.compare(other.catalogName);
if (cmpRes != 0) {
return cmpRes < 0;
}
return disambiguator < other.disambiguator;
}
std::string toString() const {
return "(" + catalogName + ", " + disambiguator + ")";
}
// The name of the index in the catalog.
std::string catalogName;
// A string used for disambiguating multiple IndexEntries with the same catalogName (such
// as in the case with a wildcard index).
std::string disambiguator;
} identifier;
BSONObj keyPattern;
const MatchExpression* filterExpr;
// What type of index is this? (What access method can we use on the index described by the
// keyPattern?)
IndexType type;
bool sparse;
// Null if this index orders strings according to the simple binary compare. If non-null,
// represents the collator used to generate index keys for indexed strings.
const CollatorInterface* collator = nullptr;
// For $** indexes, a pointer to the projection executor owned by the index access method. Null
// unless this IndexEntry represents a wildcard index, in which case this is always non-null.
const ProjectionExecAgg* wildcardProjection = nullptr;
};
/**
* An IndexEntry is a representation of an index in the catalog with parsed information which is
* helpful for query planning. Its lifetime is not tied to the underlying collection. In contrast
* to CoreIndexInfo, it includes information such as 'multikeyPaths' which can require resources to
* compute (i.e. for wildcard indexes, this requires reading the index) and so may not always be
* available.
*/
struct IndexEntry : CoreIndexInfo {
IndexEntry(const BSONObj& kp,
IndexType type,
bool mk,
const MultikeyPaths& mkp,
std::set<FieldRef> multikeyPathSet,
bool sp,
bool unq,
Identifier ident,
const MatchExpression* fe,
const BSONObj& io,
const CollatorInterface* ci,
const ProjectionExecAgg* projExec)
: CoreIndexInfo(kp, type, sp, std::move(ident), fe, ci, projExec),
multikey(mk),
multikeyPaths(mkp),
multikeyPathSet(std::move(multikeyPathSet)),
unique(unq),
infoObj(io) {
// The caller must not supply multikey metadata in two different formats.
invariant(multikeyPaths.empty() || multikeyPathSet.empty());
}
~IndexEntry() {
// An IndexEntry should never have both formats of multikey metadata simultaneously.
invariant(multikeyPaths.empty() || multikeyPathSet.empty());
}
/**
* Returns true if 'indexedField' has any multikey components. For example, returns true if this
* index has a multikey component "a", and 'indexedField' is "a.b". Illegal to call unless
* 'indexedField' is present in this index's key pattern.
*
* For indexes created on older versions we may not have path-level multikey information. In
* these cases we only have a single boolean to track whether any path in the index is multikey.
* If this is the case we defensively return true for any path.
*/
bool pathHasMultikeyComponent(StringData indexedField) const;
bool operator==(const IndexEntry& rhs) const {
// Indexes are logically equal when names are equal.
return this->identifier == rhs.identifier;
}
std::string toString() const;
bool multikey;
// If non-empty, 'multikeyPaths' is a vector with size equal to the number of elements in the
// index key pattern. Each element in the vector is an ordered set of positions (starting at 0)
// into the corresponding indexed field that represent what prefixes of the indexed field cause
// the index to be multikey.
//
// An IndexEntry may either represent multikey metadata as a fixed-size MultikeyPaths vector, or
// as an arbitrarily large set of field refs, but not both. That is, either 'multikeyPaths' or
// 'multikeyPathSet' must be empty.
MultikeyPaths multikeyPaths;
// A set of multikey paths. Used instead of 'multikeyPaths' when there could be arbitrarily many
// multikey paths associated with this index entry.
//
// An IndexEntry may either represent multikey metadata as a fixed-size MultikeyPaths vector, or
// as an arbitrarily large set of field refs, but not both. That is, either 'multikeyPaths' or
// 'multikeyPathSet' must be empty.
std::set<FieldRef> multikeyPathSet;
bool unique;
// Geo indices have extra parameters. We need those available to plan correctly.
BSONObj infoObj;
};
std::ostream& operator<<(std::ostream& stream, const IndexEntry::Identifier& ident);
StringBuilder& operator<<(StringBuilder& builder, const IndexEntry::Identifier& ident);
} // namespace mongo
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