Files
scylladb/keys.hh
Tomasz Grabiec 0330568977 db: Handle range queries on clustering key
That also includes prefix range queries (partially constrained keys).
2015-03-20 19:20:59 +01:00

327 lines
11 KiB
C++

/*
* Copyright (C) 2015 Cloudius Systems, Ltd.
*/
#pragma once
#include "schema.hh"
#include "bytes.hh"
#include "types.hh"
//
// This header defines type system for primary key holders.
//
// We distinguish partition keys and clustering keys. API-wise they are almost
// the same, but they're separate type hierarchies.
//
// Clustering keys are further divided into prefixed and non-prefixed (full).
// Non-prefixed keys always have full component set, as defined by schema.
// Prefixed ones can have any number of trailing components missing. They may
// differ in underlying representation.
//
// The main classes are:
//
// partition_key - full partition key
// clustering_key - full clustering key
// clustering_key_prefix - clustering key prefix
//
// These classes wrap only the minimum information required to store the key
// (the key value itself). Any information which can be inferred from schema
// is not stored. Therefore accessors need to be provided with a pointer to
// schema, from which information about structure is extracted.
class partition_key;
class clustering_key;
class clustering_key_prefix;
// Abstracts serialized tuple, managed by tuple_type.
template <typename TopLevel>
class tuple_wrapper {
protected:
bytes _bytes;
protected:
tuple_wrapper(bytes&& b) : _bytes(std::move(b)) {}
static inline auto get_tuple_type(const schema& s) {
return TopLevel::get_tuple_type(s);
}
public:
static TopLevel make_empty(const schema& s) {
std::vector<bytes> v;
v.resize(get_tuple_type(s)->types().size());
return from_exploded(s, v);
}
static TopLevel from_exploded(const schema& s, const std::vector<bytes>& v) {
return TopLevel::from_bytes(get_tuple_type(s)->serialize_value(v));
}
// We don't allow optional values, but provide this method as an efficient adaptor
static TopLevel from_optional_exploded(const schema& s, const std::vector<bytes_opt>& v) {
return TopLevel::from_bytes(get_tuple_type(s)->serialize_optionals(v));
}
static TopLevel from_deeply_exploded(const schema& s, const std::vector<boost::any>& v) {
return TopLevel::from_bytes(get_tuple_type(s)->serialize_value_deep(v));
}
static TopLevel from_single_value(const schema& s, bytes v) {
// FIXME: optimize
std::vector<bytes> values;
values.emplace_back(std::move(v));
return from_exploded(s, values);
}
// FIXME: return views
std::vector<bytes> explode(const schema& s) const {
return get_tuple_type(s)->deserialize_value(_bytes);
}
struct less_compare {
typename TopLevel::tuple _t;
less_compare(const schema& s) : _t(get_tuple_type(s)) {}
bool operator()(const TopLevel& k1, const TopLevel& k2) const {
return _t->less(k1, k2);
}
};
struct hashing {
typename TopLevel::tuple _t;
hashing(const schema& s) : _t(get_tuple_type(s)) {}
size_t operator()(const TopLevel& o) const {
return _t->hash(o);
}
};
struct equality {
typename TopLevel::tuple _t;
equality(const schema& s) : _t(get_tuple_type(s)) {}
bool operator()(const TopLevel& o1, const TopLevel& o2) const {
return _t->equal(o1, o2);
}
};
bool equal(const schema& s, const TopLevel& other) const {
return get_tuple_type(s)->equal(*this, other);
}
operator bytes_view() const {
return _bytes;
}
};
template <typename TopLevel, typename PrefixTopLevel>
class prefix_view_on_full_tuple {
public:
using iterator = typename tuple_type<false>::iterator;
private:
bytes_view _b;
unsigned _prefix_len;
iterator _begin;
iterator _end;
public:
prefix_view_on_full_tuple(const schema& s, bytes_view b, unsigned prefix_len)
: _b(b)
, _prefix_len(prefix_len)
, _begin(TopLevel::get_tuple_type(s)->begin(_b))
, _end(_begin)
{
std::advance(_end, prefix_len);
}
iterator begin() const { return _begin; }
iterator end() const { return _end; }
struct less_compare_with_prefix {
typename PrefixTopLevel::tuple prefix_type;
less_compare_with_prefix(const schema& s)
: prefix_type(PrefixTopLevel::get_tuple_type(s))
{ }
bool operator()(const prefix_view_on_full_tuple& k1, const PrefixTopLevel& k2) const {
return lexicographical_tri_compare(prefix_type->types().begin(),
k1.begin(), k1.end(),
prefix_type->begin(k2), prefix_type->end(k2),
tri_compare) < 0;
}
bool operator()(const PrefixTopLevel& k1, const prefix_view_on_full_tuple& k2) const {
return lexicographical_tri_compare(prefix_type->types().begin(),
prefix_type->begin(k1), prefix_type->end(k1),
k2.begin(), k2.end(),
tri_compare) < 0;
}
};
};
template <typename TopLevel, typename PrefixTopLevel>
class prefixable_full_tuple : public tuple_wrapper<TopLevel> {
using base = tuple_wrapper<TopLevel>;
protected:
prefixable_full_tuple(bytes&& b) : base(std::move(b)) {}
public:
using prefix_view_type = prefix_view_on_full_tuple<TopLevel, PrefixTopLevel>;
bool is_prefixed_by(const schema& s, const PrefixTopLevel& prefix) const {
auto t = base::get_tuple_type(s);
auto prefix_type = PrefixTopLevel::get_tuple_type(s);
return ::is_prefixed_by(t->types().begin(),
t->begin(*this), t->end(*this),
prefix_type->begin(prefix), prefix_type->end(prefix),
::equal);
}
struct less_compare_with_prefix {
typename PrefixTopLevel::tuple prefix_type;
typename TopLevel::tuple full_type;
less_compare_with_prefix(const schema& s)
: prefix_type(PrefixTopLevel::get_tuple_type(s))
, full_type(TopLevel::get_tuple_type(s))
{ }
bool operator()(const TopLevel& k1, const PrefixTopLevel& k2) const {
return lexicographical_tri_compare(prefix_type->types().begin(),
full_type->begin(k1), full_type->end(k1),
prefix_type->begin(k2), prefix_type->end(k2),
tri_compare) < 0;
}
bool operator()(const PrefixTopLevel& k1, const TopLevel& k2) const {
return lexicographical_tri_compare(prefix_type->types().begin(),
prefix_type->begin(k1), prefix_type->end(k1),
full_type->begin(k2), full_type->end(k2),
tri_compare) < 0;
}
};
// In prefix equality two sequences are equal if any of them is a prefix
// of the other. Otherwise lexicographical ordering is applied.
// Note: full tuples sorted according to lexicographical ordering are also
// sorted according to prefix equality ordering.
struct prefix_equality_less_compare {
typename PrefixTopLevel::tuple prefix_type;
typename TopLevel::tuple full_type;
prefix_equality_less_compare(const schema& s)
: prefix_type(PrefixTopLevel::get_tuple_type(s))
, full_type(TopLevel::get_tuple_type(s))
{ }
bool operator()(const TopLevel& k1, const PrefixTopLevel& k2) const {
return prefix_equality_tri_compare(prefix_type->types().begin(),
full_type->begin(k1), full_type->end(k1),
prefix_type->begin(k2), prefix_type->end(k2),
tri_compare) < 0;
}
bool operator()(const PrefixTopLevel& k1, const TopLevel& k2) const {
return prefix_equality_tri_compare(prefix_type->types().begin(),
prefix_type->begin(k1), prefix_type->end(k1),
full_type->begin(k2), full_type->end(k2),
tri_compare) < 0;
}
};
auto prefix_view(const schema& s, unsigned prefix_len) const {
return prefix_view_type(s, *this, prefix_len);
}
};
template <typename TopLevel, typename FullTopLevel>
class prefix_tuple_wrapper : public tuple_wrapper<TopLevel> {
using base = tuple_wrapper<TopLevel>;
protected:
prefix_tuple_wrapper(bytes&& b) : base(std::move(b)) {}
public:
bool is_full(const schema& s) const {
return TopLevel::get_tuple_type(s)->is_full(base::_bytes);
}
// Can be called only if is_full()
FullTopLevel to_full(const schema& s) const {
return FullTopLevel::from_exploded(s, base::explode(s));
}
bool is_prefixed_by(const schema& s, const TopLevel& prefix) const {
auto t = base::get_tuple_type(s);
return ::is_prefixed_by(t->types().begin(),
t->begin(*this), t->end(*this),
t->begin(prefix), t->end(prefix),
equal);
}
};
class partition_key : public tuple_wrapper<partition_key> {
public:
partition_key(bytes&& b) : tuple_wrapper<partition_key>(std::move(b)) {}
public:
using tuple = lw_shared_ptr<tuple_type<false>>;
static partition_key from_bytes(bytes b) { return partition_key(std::move(b)); }
static auto get_tuple_type(const schema& s) { return s.partition_key_type; }
};
class exploded_clustering_prefix {
std::vector<bytes> _v;
public:
exploded_clustering_prefix(std::vector<bytes>&& v) : _v(std::move(v)) {}
exploded_clustering_prefix() {}
size_t size() const {
return _v.size();
}
auto const& components() const {
return _v;
}
explicit operator bool() const {
return !_v.empty();
}
bool is_full(const schema& s) const {
return _v.size() == s.clustering_key_size();
}
};
class clustering_key : public prefixable_full_tuple<clustering_key, clustering_key_prefix> {
public:
clustering_key(bytes&& b) : prefixable_full_tuple<clustering_key, clustering_key_prefix>(std::move(b)) {}
public:
using tuple = lw_shared_ptr<tuple_type<false>>;
static clustering_key from_bytes(bytes b) { return clustering_key(std::move(b)); }
static auto get_tuple_type(const schema& s) { return s.clustering_key_type; }
static clustering_key from_clustering_prefix(const schema& s, const exploded_clustering_prefix& prefix) {
assert(prefix.is_full(s));
return from_exploded(s, prefix.components());
}
};
class clustering_key_prefix : public prefix_tuple_wrapper<clustering_key_prefix, clustering_key> {
clustering_key_prefix(bytes&& b) : prefix_tuple_wrapper<clustering_key_prefix, clustering_key>(std::move(b)) {}
public:
using tuple = lw_shared_ptr<tuple_type<true>>;
static clustering_key_prefix from_bytes(bytes b) { return clustering_key_prefix(std::move(b)); }
static auto get_tuple_type(const schema& s) { return s.clustering_key_prefix_type; }
static clustering_key_prefix from_clustering_prefix(const schema& s, const exploded_clustering_prefix& prefix) {
return from_exploded(s, prefix.components());
}
};
static inline
std::ostream& operator<<(std::ostream& out, const partition_key& pk) {
return out << "pk{" << to_hex(pk) << "}";
}
static inline
std::ostream& operator<<(std::ostream& out, const clustering_key& ck) {
return out << "ck{" << to_hex(ck) << "}";
}
static inline
std::ostream& operator<<(std::ostream& out, const clustering_key_prefix& ckp) {
return out << "ckp{" << to_hex(ckp) << "}";
}