d785364375
Our LSA cache is implemented as an auto_unlink Boost intrusive list, meaning that elements of the list unlink themselves from the list automatically on destruction. Some parts of the code rely on that, and don't unlink them manually. However, this precludes accurate bookkeeping about the cache. Elements only have access to themselves and their neighbours, not to any bookkeeping context. Therefore, a destructor cannot update the relevant metadata. In this patch, we fix this by adding explicit unlink calls to places where it would be done by a destructor. In a following patch, we will add an assert to the destructor to check that every element is unlinked before destruction.
954 lines
42 KiB
C++
954 lines
42 KiB
C++
/*
|
|
* Copyright (C) 2017-present ScyllaDB
|
|
*/
|
|
|
|
/*
|
|
* SPDX-License-Identifier: AGPL-3.0-or-later
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <vector>
|
|
#include "row_cache.hh"
|
|
#include "mutation_fragment.hh"
|
|
#include "query-request.hh"
|
|
#include "partition_snapshot_row_cursor.hh"
|
|
#include "range_tombstone_assembler.hh"
|
|
#include "read_context.hh"
|
|
#include "readers/delegating_v2.hh"
|
|
#include "clustering_key_filter.hh"
|
|
|
|
namespace cache {
|
|
|
|
extern logging::logger clogger;
|
|
|
|
class cache_flat_mutation_reader final : public flat_mutation_reader_v2::impl {
|
|
enum class state {
|
|
before_static_row,
|
|
|
|
// Invariants:
|
|
// - position_range(_lower_bound, _upper_bound) covers all not yet emitted positions from current range
|
|
// - if _next_row has valid iterators:
|
|
// - _next_row points to the nearest row in cache >= _lower_bound
|
|
// - _next_row_in_range = _next.position() < _upper_bound
|
|
// - if _next_row doesn't have valid iterators, it has no meaning.
|
|
reading_from_cache,
|
|
|
|
// Starts reading from underlying reader.
|
|
// The range to read is position_range(_lower_bound, min(_next_row.position(), _upper_bound)).
|
|
// Invariants:
|
|
// - _next_row_in_range = _next.position() < _upper_bound
|
|
move_to_underlying,
|
|
|
|
// Invariants:
|
|
// - Upper bound of the read is min(_next_row.position(), _upper_bound)
|
|
// - _next_row_in_range = _next.position() < _upper_bound
|
|
// - _last_row points at a direct predecessor of the next row which is going to be read.
|
|
// Used for populating continuity.
|
|
// - _population_range_starts_before_all_rows is set accordingly
|
|
// - _underlying is engaged and fast-forwarded
|
|
reading_from_underlying,
|
|
|
|
end_of_stream
|
|
};
|
|
enum class source {
|
|
cache = 0,
|
|
underlying = 1,
|
|
};
|
|
// Merges range tombstone change streams coming from underlying and the cache.
|
|
// Ensures no range tombstone change fragment is emitted when there is no
|
|
// actual change in the effective tombstone.
|
|
class range_tombstone_change_merger {
|
|
const schema& _schema;
|
|
position_in_partition _pos;
|
|
tombstone _current_tombstone;
|
|
std::array<tombstone, 2> _tombstones;
|
|
private:
|
|
std::optional<range_tombstone_change> do_flush(position_in_partition pos, bool end_of_range) {
|
|
std::optional<range_tombstone_change> ret;
|
|
position_in_partition::tri_compare cmp(_schema);
|
|
const auto res = cmp(_pos, pos);
|
|
const auto should_flush = end_of_range ? res <= 0 : res < 0;
|
|
if (should_flush) {
|
|
auto merged_tomb = std::max(_tombstones.front(), _tombstones.back());
|
|
if (merged_tomb != _current_tombstone) {
|
|
_current_tombstone = merged_tomb;
|
|
ret.emplace(_pos, _current_tombstone);
|
|
}
|
|
_pos = std::move(pos);
|
|
}
|
|
return ret;
|
|
}
|
|
public:
|
|
range_tombstone_change_merger(const schema& s) : _schema(s), _pos(position_in_partition::before_all_clustered_rows()), _tombstones{}
|
|
{ }
|
|
std::optional<range_tombstone_change> apply(source src, range_tombstone_change&& rtc) {
|
|
auto ret = do_flush(rtc.position(), false);
|
|
_tombstones[static_cast<size_t>(src)] = rtc.tombstone();
|
|
return ret;
|
|
}
|
|
std::optional<range_tombstone_change> flush(position_in_partition_view pos, bool end_of_range) {
|
|
return do_flush(position_in_partition(pos), end_of_range);
|
|
}
|
|
};
|
|
partition_snapshot_ptr _snp;
|
|
|
|
query::clustering_key_filter_ranges _ck_ranges; // Query schema domain, reversed reads use native order
|
|
query::clustering_row_ranges::const_iterator _ck_ranges_curr; // Query schema domain
|
|
query::clustering_row_ranges::const_iterator _ck_ranges_end; // Query schema domain
|
|
|
|
lsa_manager _lsa_manager;
|
|
|
|
partition_snapshot_row_weakref _last_row; // Table schema domain
|
|
|
|
// Holds the lower bound of a position range which hasn't been processed yet.
|
|
// Only rows with positions < _lower_bound have been emitted, and only
|
|
// range_tombstones with positions <= _lower_bound.
|
|
position_in_partition _lower_bound; // Query schema domain
|
|
position_in_partition_view _upper_bound; // Query schema domain
|
|
std::optional<position_in_partition> _underlying_upper_bound; // Query schema domain
|
|
|
|
// cache_flat_mutation_reader may be constructed either
|
|
// with a read_context&, where it knows that the read_context
|
|
// is owned externally, by the caller. In this case
|
|
// _read_context_holder would be disengaged.
|
|
// Or, it could be constructed with a std::unique_ptr<read_context>,
|
|
// in which case it assumes ownership of the read_context
|
|
// and it is now responsible for closing it.
|
|
// In this case, _read_context_holder would be engaged
|
|
// and _read_context will reference its content.
|
|
std::unique_ptr<read_context> _read_context_holder;
|
|
read_context& _read_context;
|
|
partition_snapshot_row_cursor _next_row;
|
|
|
|
range_tombstone_change_generator _rt_gen; // cache -> reader
|
|
range_tombstone_assembler _rt_assembler; // underlying -> cache
|
|
range_tombstone_change_merger _rt_merger; // {cache, underlying} -> reader
|
|
|
|
// When the read moves to the underlying, the read range will be
|
|
// (_lower_bound, x], where x is either _next_row.position() or _upper_bound.
|
|
// In the former case (x is _next_row.position()), underlying can emit
|
|
// a range tombstone change for after_key(x), which is outside the range.
|
|
// We can't push this fragment into the buffer straight away, the cache may
|
|
// have fragments with smaller position. So we save it here and flush it when
|
|
// a fragment with a larger position is seen.
|
|
std::optional<mutation_fragment_v2> _queued_underlying_fragment;
|
|
|
|
state _state = state::before_static_row;
|
|
|
|
bool _next_row_in_range = false;
|
|
|
|
// True iff current population interval, since the previous clustering row, starts before all clustered rows.
|
|
// We cannot just look at _lower_bound, because emission of range tombstones changes _lower_bound and
|
|
// because we mark clustering intervals as continuous when consuming a clustering_row, it would prevent
|
|
// us from marking the interval as continuous.
|
|
// Valid when _state == reading_from_underlying.
|
|
bool _population_range_starts_before_all_rows;
|
|
|
|
// Whether _lower_bound was changed within current fill_buffer().
|
|
// If it did not then we cannot break out of it (e.g. on preemption) because
|
|
// forward progress is not guaranteed in case iterators are getting constantly invalidated.
|
|
bool _lower_bound_changed = false;
|
|
|
|
// Points to the underlying reader conforming to _schema,
|
|
// either to *_underlying_holder or _read_context.underlying().underlying().
|
|
flat_mutation_reader_v2* _underlying = nullptr;
|
|
flat_mutation_reader_v2_opt _underlying_holder;
|
|
|
|
future<> do_fill_buffer();
|
|
future<> ensure_underlying();
|
|
void copy_from_cache_to_buffer();
|
|
future<> process_static_row();
|
|
void move_to_end();
|
|
void move_to_next_range();
|
|
void move_to_range(query::clustering_row_ranges::const_iterator);
|
|
void move_to_next_entry();
|
|
void maybe_drop_last_entry() noexcept;
|
|
void flush_tombstones(position_in_partition_view, bool end_of_range = false);
|
|
void add_to_buffer(const partition_snapshot_row_cursor&);
|
|
void add_clustering_row_to_buffer(mutation_fragment_v2&&);
|
|
void add_to_buffer(range_tombstone_change&&, source);
|
|
void do_add_to_buffer(range_tombstone_change&&);
|
|
void add_range_tombstone_to_buffer(range_tombstone&&);
|
|
void add_to_buffer(mutation_fragment_v2&&);
|
|
future<> read_from_underlying();
|
|
void start_reading_from_underlying();
|
|
bool after_current_range(position_in_partition_view position);
|
|
bool can_populate() const;
|
|
// Marks the range between _last_row (exclusive) and _next_row (exclusive) as continuous,
|
|
// provided that the underlying reader still matches the latest version of the partition.
|
|
// Invalidates _last_row.
|
|
void maybe_update_continuity();
|
|
// Tries to ensure that the lower bound of the current population range exists.
|
|
// Returns false if it failed and range cannot be populated.
|
|
// Assumes can_populate().
|
|
// If returns true then _last_row is refreshed and points to the population lower bound.
|
|
// if _read_context.is_reversed() then _last_row is always valid after this.
|
|
// if !_read_context.is_reversed() then _last_row is valid after this or the population lower bound
|
|
// is before all rows (so _last_row doesn't point at any entry).
|
|
bool ensure_population_lower_bound();
|
|
void maybe_add_to_cache(const mutation_fragment_v2& mf);
|
|
void maybe_add_to_cache(const clustering_row& cr);
|
|
void maybe_add_to_cache(const range_tombstone_change& rtc);
|
|
void maybe_add_to_cache(const static_row& sr);
|
|
void maybe_set_static_row_continuous();
|
|
void finish_reader() {
|
|
push_mutation_fragment(*_schema, _permit, partition_end());
|
|
_end_of_stream = true;
|
|
_state = state::end_of_stream;
|
|
}
|
|
const schema_ptr& snp_schema() const {
|
|
return _snp->schema();
|
|
}
|
|
void touch_partition();
|
|
|
|
position_in_partition_view to_table_domain(position_in_partition_view query_domain_pos) {
|
|
if (!_read_context.is_reversed()) [[likely]] {
|
|
return query_domain_pos;
|
|
}
|
|
return query_domain_pos.reversed();
|
|
}
|
|
|
|
range_tombstone to_table_domain(range_tombstone query_domain_rt) {
|
|
if (_read_context.is_reversed()) [[unlikely]] {
|
|
query_domain_rt.reverse();
|
|
}
|
|
return query_domain_rt;
|
|
}
|
|
|
|
position_in_partition_view to_query_domain(position_in_partition_view table_domain_pos) {
|
|
if (!_read_context.is_reversed()) [[likely]] {
|
|
return table_domain_pos;
|
|
}
|
|
return table_domain_pos.reversed();
|
|
}
|
|
|
|
const schema& table_schema() {
|
|
return *_snp->schema();
|
|
}
|
|
public:
|
|
cache_flat_mutation_reader(schema_ptr s,
|
|
dht::decorated_key dk,
|
|
query::clustering_key_filter_ranges&& crr,
|
|
read_context& ctx,
|
|
partition_snapshot_ptr snp,
|
|
row_cache& cache)
|
|
: flat_mutation_reader_v2::impl(std::move(s), ctx.permit())
|
|
, _snp(std::move(snp))
|
|
, _ck_ranges(std::move(crr))
|
|
, _ck_ranges_curr(_ck_ranges.begin())
|
|
, _ck_ranges_end(_ck_ranges.end())
|
|
, _lsa_manager(cache)
|
|
, _lower_bound(position_in_partition::before_all_clustered_rows())
|
|
, _upper_bound(position_in_partition_view::before_all_clustered_rows())
|
|
, _read_context_holder()
|
|
, _read_context(ctx) // ctx is owned by the caller, who's responsible for closing it.
|
|
, _next_row(*_schema, *_snp, false, _read_context.is_reversed())
|
|
, _rt_gen(*_schema)
|
|
, _rt_merger(*_schema)
|
|
{
|
|
clogger.trace("csm {}: table={}.{}, reversed={}, snap={}", fmt::ptr(this), _schema->ks_name(), _schema->cf_name(), _read_context.is_reversed(),
|
|
fmt::ptr(&*_snp));
|
|
push_mutation_fragment(*_schema, _permit, partition_start(std::move(dk), _snp->partition_tombstone()));
|
|
}
|
|
cache_flat_mutation_reader(schema_ptr s,
|
|
dht::decorated_key dk,
|
|
query::clustering_key_filter_ranges&& crr,
|
|
std::unique_ptr<read_context> unique_ctx,
|
|
partition_snapshot_ptr snp,
|
|
row_cache& cache)
|
|
: cache_flat_mutation_reader(s, std::move(dk), std::move(crr), *unique_ctx, std::move(snp), cache)
|
|
{
|
|
// Assume ownership of the read_context.
|
|
// It is our responsibility to close it now.
|
|
_read_context_holder = std::move(unique_ctx);
|
|
}
|
|
cache_flat_mutation_reader(const cache_flat_mutation_reader&) = delete;
|
|
cache_flat_mutation_reader(cache_flat_mutation_reader&&) = delete;
|
|
virtual future<> fill_buffer() override;
|
|
virtual future<> next_partition() override {
|
|
clear_buffer_to_next_partition();
|
|
if (is_buffer_empty()) {
|
|
_end_of_stream = true;
|
|
}
|
|
return make_ready_future<>();
|
|
}
|
|
virtual future<> fast_forward_to(const dht::partition_range&) override {
|
|
clear_buffer();
|
|
_end_of_stream = true;
|
|
return make_ready_future<>();
|
|
}
|
|
virtual future<> fast_forward_to(position_range pr) override {
|
|
return make_exception_future<>(make_backtraced_exception_ptr<std::bad_function_call>());
|
|
}
|
|
virtual future<> close() noexcept override {
|
|
auto close_read_context = _read_context_holder ? _read_context_holder->close() : make_ready_future<>();
|
|
auto close_underlying = _underlying_holder ? _underlying_holder->close() : make_ready_future<>();
|
|
return when_all_succeed(std::move(close_read_context), std::move(close_underlying)).discard_result();
|
|
}
|
|
};
|
|
|
|
inline
|
|
future<> cache_flat_mutation_reader::process_static_row() {
|
|
if (_snp->static_row_continuous()) {
|
|
_read_context.cache().on_row_hit();
|
|
static_row sr = _lsa_manager.run_in_read_section([this] {
|
|
return _snp->static_row(_read_context.digest_requested());
|
|
});
|
|
if (!sr.empty()) {
|
|
push_mutation_fragment(*_schema, _permit, std::move(sr));
|
|
}
|
|
return make_ready_future<>();
|
|
} else {
|
|
_read_context.cache().on_row_miss();
|
|
return ensure_underlying().then([this] {
|
|
return (*_underlying)().then([this] (mutation_fragment_v2_opt&& sr) {
|
|
if (sr) {
|
|
assert(sr->is_static_row());
|
|
maybe_add_to_cache(sr->as_static_row());
|
|
push_mutation_fragment(std::move(*sr));
|
|
}
|
|
maybe_set_static_row_continuous();
|
|
});
|
|
});
|
|
}
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::touch_partition() {
|
|
_snp->touch();
|
|
}
|
|
|
|
inline
|
|
future<> cache_flat_mutation_reader::fill_buffer() {
|
|
if (_state == state::before_static_row) {
|
|
touch_partition();
|
|
auto after_static_row = [this] {
|
|
if (_ck_ranges_curr == _ck_ranges_end) {
|
|
finish_reader();
|
|
return make_ready_future<>();
|
|
}
|
|
_state = state::reading_from_cache;
|
|
_lsa_manager.run_in_read_section([this] {
|
|
move_to_range(_ck_ranges_curr);
|
|
});
|
|
return fill_buffer();
|
|
};
|
|
if (_schema->has_static_columns()) {
|
|
return process_static_row().then(std::move(after_static_row));
|
|
} else {
|
|
return after_static_row();
|
|
}
|
|
}
|
|
clogger.trace("csm {}: fill_buffer(), range={}, lb={}", fmt::ptr(this), *_ck_ranges_curr, _lower_bound);
|
|
return do_until([this] { return _end_of_stream || is_buffer_full(); }, [this] {
|
|
return do_fill_buffer();
|
|
});
|
|
}
|
|
|
|
inline
|
|
future<> cache_flat_mutation_reader::ensure_underlying() {
|
|
if (_underlying) {
|
|
return make_ready_future<>();
|
|
}
|
|
return _read_context.ensure_underlying().then([this] {
|
|
flat_mutation_reader_v2& ctx_underlying = _read_context.underlying().underlying();
|
|
if (ctx_underlying.schema() != _schema) {
|
|
_underlying_holder = make_delegating_reader(ctx_underlying);
|
|
_underlying_holder->upgrade_schema(_schema);
|
|
_underlying = &*_underlying_holder;
|
|
} else {
|
|
_underlying = &ctx_underlying;
|
|
}
|
|
});
|
|
}
|
|
|
|
inline
|
|
future<> cache_flat_mutation_reader::do_fill_buffer() {
|
|
if (_state == state::move_to_underlying) {
|
|
if (!_underlying) {
|
|
return ensure_underlying().then([this] {
|
|
return do_fill_buffer();
|
|
});
|
|
}
|
|
_state = state::reading_from_underlying;
|
|
_population_range_starts_before_all_rows = _lower_bound.is_before_all_clustered_rows(*_schema) && !_read_context.is_reversed();
|
|
if (!_read_context.partition_exists()) {
|
|
return read_from_underlying();
|
|
}
|
|
_underlying_upper_bound = _next_row_in_range ? position_in_partition(_next_row.position())
|
|
: position_in_partition(_upper_bound);
|
|
return _underlying->fast_forward_to(position_range{_lower_bound, *_underlying_upper_bound}).then([this] {
|
|
return read_from_underlying();
|
|
});
|
|
}
|
|
if (_state == state::reading_from_underlying) {
|
|
return read_from_underlying();
|
|
}
|
|
// assert(_state == state::reading_from_cache)
|
|
return _lsa_manager.run_in_read_section([this] {
|
|
auto next_valid = _next_row.iterators_valid();
|
|
clogger.trace("csm {}: reading_from_cache, range=[{}, {}), next={}, valid={}", fmt::ptr(this), _lower_bound,
|
|
_upper_bound, _next_row.position(), next_valid);
|
|
// We assume that if there was eviction, and thus the range may
|
|
// no longer be continuous, the cursor was invalidated.
|
|
if (!next_valid) {
|
|
auto adjacent = _next_row.advance_to(_lower_bound);
|
|
_next_row_in_range = !after_current_range(_next_row.position());
|
|
if (!adjacent && !_next_row.continuous()) {
|
|
_last_row = nullptr; // We could insert a dummy here, but this path is unlikely.
|
|
start_reading_from_underlying();
|
|
return make_ready_future<>();
|
|
}
|
|
}
|
|
_next_row.maybe_refresh();
|
|
clogger.trace("csm {}: next={}", fmt::ptr(this), _next_row);
|
|
_lower_bound_changed = false;
|
|
while (_state == state::reading_from_cache) {
|
|
copy_from_cache_to_buffer();
|
|
// We need to check _lower_bound_changed even if is_buffer_full() because
|
|
// we may have emitted only a range tombstone which overlapped with _lower_bound
|
|
// and thus didn't cause _lower_bound to change.
|
|
if ((need_preempt() || is_buffer_full()) && _lower_bound_changed) {
|
|
break;
|
|
}
|
|
}
|
|
return make_ready_future<>();
|
|
});
|
|
}
|
|
|
|
inline
|
|
future<> cache_flat_mutation_reader::read_from_underlying() {
|
|
return consume_mutation_fragments_until(*_underlying,
|
|
[this] { return _state != state::reading_from_underlying || is_buffer_full(); },
|
|
[this] (mutation_fragment_v2 mf) {
|
|
_read_context.cache().on_row_miss();
|
|
maybe_add_to_cache(mf);
|
|
add_to_buffer(std::move(mf));
|
|
},
|
|
[this] {
|
|
_underlying_upper_bound.reset();
|
|
_state = state::reading_from_cache;
|
|
_lsa_manager.run_in_update_section([this] {
|
|
auto same_pos = _next_row.maybe_refresh();
|
|
if (!same_pos) {
|
|
_read_context.cache().on_mispopulate(); // FIXME: Insert dummy entry at _upper_bound.
|
|
_next_row_in_range = !after_current_range(_next_row.position());
|
|
if (!_next_row.continuous()) {
|
|
start_reading_from_underlying();
|
|
}
|
|
return;
|
|
}
|
|
if (_next_row_in_range) {
|
|
maybe_update_continuity();
|
|
if (!_next_row.dummy()) {
|
|
_lower_bound = position_in_partition::before_key(_next_row.key());
|
|
} else {
|
|
_lower_bound = _next_row.position();
|
|
}
|
|
} else {
|
|
if (no_clustering_row_between(*_schema, _upper_bound, _next_row.position())) {
|
|
this->maybe_update_continuity();
|
|
} else if (can_populate()) {
|
|
const schema& table_s = table_schema();
|
|
rows_entry::tri_compare cmp(table_s);
|
|
auto& rows = _snp->version()->partition().mutable_clustered_rows();
|
|
if (query::is_single_row(*_schema, *_ck_ranges_curr)) {
|
|
with_allocator(_snp->region().allocator(), [&] {
|
|
auto e = alloc_strategy_unique_ptr<rows_entry>(
|
|
current_allocator().construct<rows_entry>(_ck_ranges_curr->start()->value()));
|
|
// Use _next_row iterator only as a hint, because there could be insertions after _upper_bound.
|
|
auto insert_result = rows.insert_before_hint(_next_row.get_iterator_in_latest_version(), std::move(e), cmp);
|
|
if (insert_result.second) {
|
|
auto it = insert_result.first;
|
|
_snp->tracker()->insert(*it);
|
|
auto next = std::next(it);
|
|
// Also works in reverse read mode.
|
|
// It preserves the continuity of the range the entry falls into.
|
|
it->set_continuous(next->continuous());
|
|
clogger.trace("csm {}: inserted empty row at {}, cont={}", fmt::ptr(this), it->position(), it->continuous());
|
|
}
|
|
});
|
|
} else if (ensure_population_lower_bound()) {
|
|
with_allocator(_snp->region().allocator(), [&] {
|
|
auto e = alloc_strategy_unique_ptr<rows_entry>(
|
|
current_allocator().construct<rows_entry>(table_s, to_table_domain(_upper_bound), is_dummy::yes, is_continuous::no));
|
|
// Use _next_row iterator only as a hint, because there could be insertions after _upper_bound.
|
|
auto insert_result = rows.insert_before_hint(_next_row.get_iterator_in_latest_version(), std::move(e), cmp);
|
|
if (insert_result.second) {
|
|
clogger.trace("csm {}: inserted dummy at {}", fmt::ptr(this), _upper_bound);
|
|
_snp->tracker()->insert(*insert_result.first);
|
|
}
|
|
if (_read_context.is_reversed()) [[unlikely]] {
|
|
clogger.trace("csm {}: set_continuous({})", fmt::ptr(this), _last_row.position());
|
|
_last_row->set_continuous(true);
|
|
} else {
|
|
clogger.trace("csm {}: set_continuous({})", fmt::ptr(this), insert_result.first->position());
|
|
insert_result.first->set_continuous(true);
|
|
}
|
|
maybe_drop_last_entry();
|
|
});
|
|
}
|
|
} else {
|
|
_read_context.cache().on_mispopulate();
|
|
}
|
|
try {
|
|
move_to_next_range();
|
|
} catch (const std::bad_alloc&) {
|
|
// We cannot reenter the section, since we may have moved to the new range
|
|
_snp->region().allocator().invalidate_references(); // Invalidates _next_row
|
|
}
|
|
}
|
|
});
|
|
return make_ready_future<>();
|
|
});
|
|
}
|
|
|
|
inline
|
|
bool cache_flat_mutation_reader::ensure_population_lower_bound() {
|
|
if (_population_range_starts_before_all_rows) {
|
|
return true;
|
|
}
|
|
if (!_last_row.refresh(*_snp)) {
|
|
return false;
|
|
}
|
|
// Continuity flag we will later set for the upper bound extends to the previous row in the same version,
|
|
// so we need to ensure we have an entry in the latest version.
|
|
if (!_last_row.is_in_latest_version()) {
|
|
with_allocator(_snp->region().allocator(), [&] {
|
|
auto& rows = _snp->version()->partition().mutable_clustered_rows();
|
|
rows_entry::tri_compare cmp(table_schema());
|
|
// FIXME: Avoid the copy by inserting an incomplete clustering row
|
|
auto e = alloc_strategy_unique_ptr<rows_entry>(
|
|
current_allocator().construct<rows_entry>(table_schema(), *_last_row));
|
|
e->set_continuous(false);
|
|
auto insert_result = rows.insert_before_hint(rows.end(), std::move(e), cmp);
|
|
if (insert_result.second) {
|
|
auto it = insert_result.first;
|
|
clogger.trace("csm {}: inserted lower bound dummy at {}", fmt::ptr(this), it->position());
|
|
_snp->tracker()->insert(*it);
|
|
}
|
|
_last_row.set_latest(insert_result.first);
|
|
});
|
|
}
|
|
return true;
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::maybe_update_continuity() {
|
|
if (can_populate() && ensure_population_lower_bound()) {
|
|
with_allocator(_snp->region().allocator(), [&] {
|
|
rows_entry& e = _next_row.ensure_entry_in_latest().row;
|
|
if (_read_context.is_reversed()) [[unlikely]] {
|
|
clogger.trace("csm {}: set_continuous({})", fmt::ptr(this), _last_row.position());
|
|
_last_row->set_continuous(true);
|
|
} else {
|
|
clogger.trace("csm {}: set_continuous({})", fmt::ptr(this), e.position());
|
|
e.set_continuous(true);
|
|
}
|
|
maybe_drop_last_entry();
|
|
});
|
|
} else {
|
|
_read_context.cache().on_mispopulate();
|
|
}
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::maybe_add_to_cache(const mutation_fragment_v2& mf) {
|
|
if (mf.is_range_tombstone_change()) {
|
|
maybe_add_to_cache(mf.as_range_tombstone_change());
|
|
} else {
|
|
assert(mf.is_clustering_row());
|
|
const clustering_row& cr = mf.as_clustering_row();
|
|
maybe_add_to_cache(cr);
|
|
}
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::maybe_add_to_cache(const clustering_row& cr) {
|
|
if (!can_populate()) {
|
|
_last_row = nullptr;
|
|
_population_range_starts_before_all_rows = false;
|
|
_read_context.cache().on_mispopulate();
|
|
return;
|
|
}
|
|
auto rt_opt = _rt_assembler.flush(*_schema, position_in_partition::after_key(cr.key()));
|
|
clogger.trace("csm {}: populate({})", fmt::ptr(this), clustering_row::printer(*_schema, cr));
|
|
_lsa_manager.run_in_update_section_with_allocator([this, &cr, &rt_opt] {
|
|
mutation_partition& mp = _snp->version()->partition();
|
|
|
|
if (rt_opt) {
|
|
clogger.trace("csm {}: populate flushed rt({})", fmt::ptr(this), *rt_opt);
|
|
mp.mutable_row_tombstones().apply_monotonically(table_schema(), to_table_domain(range_tombstone(*rt_opt)));
|
|
}
|
|
|
|
rows_entry::tri_compare cmp(table_schema());
|
|
|
|
if (_read_context.digest_requested()) {
|
|
cr.cells().prepare_hash(*_schema, column_kind::regular_column);
|
|
}
|
|
auto new_entry = alloc_strategy_unique_ptr<rows_entry>(
|
|
current_allocator().construct<rows_entry>(table_schema(), cr.key(), cr.as_deletable_row()));
|
|
new_entry->set_continuous(false);
|
|
auto it = _next_row.iterators_valid() ? _next_row.get_iterator_in_latest_version()
|
|
: mp.clustered_rows().lower_bound(cr.key(), cmp);
|
|
auto insert_result = mp.mutable_clustered_rows().insert_before_hint(it, std::move(new_entry), cmp);
|
|
it = insert_result.first;
|
|
if (insert_result.second) {
|
|
_snp->tracker()->insert(*it);
|
|
}
|
|
|
|
rows_entry& e = *it;
|
|
if (ensure_population_lower_bound()) {
|
|
if (_read_context.is_reversed()) [[unlikely]] {
|
|
clogger.trace("csm {}: set_continuous({})", fmt::ptr(this), _last_row.position());
|
|
_last_row->set_continuous(true);
|
|
} else {
|
|
clogger.trace("csm {}: set_continuous({})", fmt::ptr(this), e.position());
|
|
e.set_continuous(true);
|
|
}
|
|
} else {
|
|
_read_context.cache().on_mispopulate();
|
|
}
|
|
with_allocator(standard_allocator(), [&] {
|
|
_last_row = partition_snapshot_row_weakref(*_snp, it, true);
|
|
});
|
|
_population_range_starts_before_all_rows = false;
|
|
});
|
|
}
|
|
|
|
inline
|
|
bool cache_flat_mutation_reader::after_current_range(position_in_partition_view p) {
|
|
position_in_partition::tri_compare cmp(*_schema);
|
|
return cmp(p, _upper_bound) >= 0;
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::start_reading_from_underlying() {
|
|
clogger.trace("csm {}: start_reading_from_underlying(), range=[{}, {})", fmt::ptr(this), _lower_bound, _next_row_in_range ? _next_row.position() : _upper_bound);
|
|
_state = state::move_to_underlying;
|
|
_next_row.touch();
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::copy_from_cache_to_buffer() {
|
|
clogger.trace("csm {}: copy_from_cache, next={}, next_row_in_range={}", fmt::ptr(this), _next_row.position(), _next_row_in_range);
|
|
_next_row.touch();
|
|
position_in_partition_view next_lower_bound = _next_row.dummy() ? _next_row.position() : position_in_partition_view::after_key(_next_row.key());
|
|
auto upper_bound = _next_row_in_range ? next_lower_bound : _upper_bound;
|
|
if (_snp->range_tombstones(_lower_bound, upper_bound, [&] (range_tombstone rts) {
|
|
add_range_tombstone_to_buffer(std::move(rts));
|
|
return stop_iteration(_lower_bound_changed && is_buffer_full());
|
|
}, _read_context.is_reversed()) == stop_iteration::no) {
|
|
return;
|
|
}
|
|
// We add the row to the buffer even when it's full.
|
|
// This simplifies the code. For more info see #3139.
|
|
if (_next_row_in_range) {
|
|
add_to_buffer(_next_row);
|
|
move_to_next_entry();
|
|
} else {
|
|
move_to_next_range();
|
|
}
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::move_to_end() {
|
|
finish_reader();
|
|
clogger.trace("csm {}: eos", fmt::ptr(this));
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::move_to_next_range() {
|
|
if (_queued_underlying_fragment) {
|
|
add_to_buffer(*std::exchange(_queued_underlying_fragment, {}));
|
|
}
|
|
flush_tombstones(position_in_partition::for_range_end(*_ck_ranges_curr), true);
|
|
auto next_it = std::next(_ck_ranges_curr);
|
|
if (next_it == _ck_ranges_end) {
|
|
move_to_end();
|
|
_ck_ranges_curr = next_it;
|
|
} else {
|
|
move_to_range(next_it);
|
|
}
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::move_to_range(query::clustering_row_ranges::const_iterator next_it) {
|
|
auto lb = position_in_partition::for_range_start(*next_it);
|
|
auto ub = position_in_partition_view::for_range_end(*next_it);
|
|
_last_row = nullptr;
|
|
_lower_bound = std::move(lb);
|
|
_upper_bound = std::move(ub);
|
|
_rt_gen.trim(_lower_bound);
|
|
_lower_bound_changed = true;
|
|
_ck_ranges_curr = next_it;
|
|
auto adjacent = _next_row.advance_to(_lower_bound);
|
|
_next_row_in_range = !after_current_range(_next_row.position());
|
|
clogger.trace("csm {}: move_to_range(), range={}, lb={}, ub={}, next={}", fmt::ptr(this), *_ck_ranges_curr, _lower_bound, _upper_bound, _next_row.position());
|
|
if (!adjacent && !_next_row.continuous()) {
|
|
// FIXME: We don't insert a dummy for singular range to avoid allocating 3 entries
|
|
// for a hit (before, at and after). If we supported the concept of an incomplete row,
|
|
// we could insert such a row for the lower bound if it's full instead, for both singular and
|
|
// non-singular ranges.
|
|
if (_ck_ranges_curr->start() && !query::is_single_row(*_schema, *_ck_ranges_curr)) {
|
|
// Insert dummy for lower bound
|
|
if (can_populate()) {
|
|
// FIXME: _lower_bound could be adjacent to the previous row, in which case we could skip this
|
|
clogger.trace("csm {}: insert dummy at {}", fmt::ptr(this), _lower_bound);
|
|
auto insert_result = with_allocator(_lsa_manager.region().allocator(), [&] {
|
|
rows_entry::tri_compare cmp(table_schema());
|
|
auto& rows = _snp->version()->partition().mutable_clustered_rows();
|
|
auto new_entry = alloc_strategy_unique_ptr<rows_entry>(current_allocator().construct<rows_entry>(table_schema(),
|
|
to_table_domain(_lower_bound), is_dummy::yes, is_continuous::no));
|
|
return rows.insert_before_hint(_next_row.get_iterator_in_latest_version(), std::move(new_entry), cmp);
|
|
});
|
|
auto it = insert_result.first;
|
|
if (insert_result.second) {
|
|
_snp->tracker()->insert(*it);
|
|
}
|
|
_last_row = partition_snapshot_row_weakref(*_snp, it, true);
|
|
} else {
|
|
_read_context.cache().on_mispopulate();
|
|
}
|
|
}
|
|
start_reading_from_underlying();
|
|
}
|
|
}
|
|
|
|
// Drops _last_row entry when possible without changing logical contents of the partition.
|
|
// Call only when _last_row and _next_row are valid.
|
|
// Calling after ensure_population_lower_bound() is ok.
|
|
// _next_row must have a greater position than _last_row.
|
|
// Invalidates references but keeps the _next_row valid.
|
|
inline
|
|
void cache_flat_mutation_reader::maybe_drop_last_entry() noexcept {
|
|
// Drop dummy entry if it falls inside a continuous range.
|
|
// This prevents unnecessary dummy entries from accumulating in cache and slowing down scans.
|
|
//
|
|
// Eviction can happen only from oldest versions to preserve the continuity non-overlapping rule
|
|
// (See docs/dev/row_cache.md)
|
|
//
|
|
if (_last_row
|
|
&& !_read_context.is_reversed() // FIXME
|
|
&& _last_row->dummy()
|
|
&& _last_row->continuous()
|
|
&& _snp->at_latest_version()
|
|
&& _snp->at_oldest_version()) {
|
|
|
|
with_allocator(_snp->region().allocator(), [&] {
|
|
cache_tracker& tracker = _read_context.cache()._tracker;
|
|
tracker.get_lru().remove(*_last_row);
|
|
_last_row->on_evicted(tracker);
|
|
});
|
|
_last_row = nullptr;
|
|
|
|
// There could be iterators pointing to _last_row, invalidate them
|
|
_snp->region().allocator().invalidate_references();
|
|
|
|
// Don't invalidate _next_row, move_to_next_entry() expects it to be still valid.
|
|
_next_row.force_valid();
|
|
}
|
|
}
|
|
|
|
// _next_row must be inside the range.
|
|
inline
|
|
void cache_flat_mutation_reader::move_to_next_entry() {
|
|
clogger.trace("csm {}: move_to_next_entry(), curr={}", fmt::ptr(this), _next_row.position());
|
|
if (no_clustering_row_between(*_schema, _next_row.position(), _upper_bound)) {
|
|
move_to_next_range();
|
|
} else {
|
|
auto new_last_row = partition_snapshot_row_weakref(_next_row);
|
|
// In reverse mode, the cursor may fall out of the entries because there is no dummy before all rows.
|
|
// Hence !next() doesn't mean we can end the read. The cursor will be positioned before all rows and
|
|
// not point at any row. continuous() is still correctly set.
|
|
_next_row.next();
|
|
_last_row = std::move(new_last_row);
|
|
_next_row_in_range = !after_current_range(_next_row.position());
|
|
clogger.trace("csm {}: next={}, cont={}, in_range={}", fmt::ptr(this), _next_row.position(), _next_row.continuous(), _next_row_in_range);
|
|
if (!_next_row.continuous()) {
|
|
start_reading_from_underlying();
|
|
} else {
|
|
maybe_drop_last_entry();
|
|
}
|
|
}
|
|
}
|
|
|
|
void cache_flat_mutation_reader::flush_tombstones(position_in_partition_view pos, bool end_of_range) {
|
|
// Ensure position is appropriate for range tombstone bound
|
|
pos = position_in_partition_view::after_key(pos);
|
|
clogger.trace("csm {}: flush_tombstones({}) end_of_range: {}", fmt::ptr(this), pos, end_of_range);
|
|
_rt_gen.flush(pos, [this] (range_tombstone_change&& rtc) {
|
|
add_to_buffer(std::move(rtc), source::cache);
|
|
}, end_of_range);
|
|
if (auto rtc_opt = _rt_merger.flush(pos, end_of_range)) {
|
|
do_add_to_buffer(std::move(*rtc_opt));
|
|
}
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::add_to_buffer(mutation_fragment_v2&& mf) {
|
|
clogger.trace("csm {}: add_to_buffer({})", fmt::ptr(this), mutation_fragment_v2::printer(*_schema, mf));
|
|
position_in_partition::less_compare less(*_schema);
|
|
if (_underlying_upper_bound && less(*_underlying_upper_bound, mf.position())) {
|
|
_queued_underlying_fragment = std::move(mf);
|
|
return;
|
|
}
|
|
flush_tombstones(mf.position());
|
|
if (mf.is_clustering_row()) {
|
|
add_clustering_row_to_buffer(std::move(mf));
|
|
} else {
|
|
assert(mf.is_range_tombstone_change());
|
|
add_to_buffer(std::move(mf).as_range_tombstone_change(), source::underlying);
|
|
}
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::add_to_buffer(const partition_snapshot_row_cursor& row) {
|
|
position_in_partition::less_compare less(*_schema);
|
|
if (_queued_underlying_fragment && less(_queued_underlying_fragment->position(), row.position())) {
|
|
add_to_buffer(*std::exchange(_queued_underlying_fragment, {}));
|
|
}
|
|
if (!row.dummy()) {
|
|
_read_context.cache().on_row_hit();
|
|
if (_read_context.digest_requested()) {
|
|
row.latest_row().cells().prepare_hash(table_schema(), column_kind::regular_column);
|
|
}
|
|
flush_tombstones(position_in_partition_view::for_key(row.key()));
|
|
add_clustering_row_to_buffer(mutation_fragment_v2(*_schema, _permit, row.row()));
|
|
} else {
|
|
if (less(_lower_bound, row.position())) {
|
|
_lower_bound = row.position();
|
|
_lower_bound_changed = true;
|
|
}
|
|
_read_context.cache()._tracker.on_dummy_row_hit();
|
|
}
|
|
}
|
|
|
|
// Maintains the following invariants, also in case of exception:
|
|
// (1) no fragment with position >= _lower_bound was pushed yet
|
|
// (2) If _lower_bound > mf.position(), mf was emitted
|
|
inline
|
|
void cache_flat_mutation_reader::add_clustering_row_to_buffer(mutation_fragment_v2&& mf) {
|
|
clogger.trace("csm {}: add_clustering_row_to_buffer({})", fmt::ptr(this), mutation_fragment_v2::printer(*_schema, mf));
|
|
auto& row = mf.as_clustering_row();
|
|
auto new_lower_bound = position_in_partition::after_key(row.key());
|
|
push_mutation_fragment(std::move(mf));
|
|
_lower_bound = std::move(new_lower_bound);
|
|
_lower_bound_changed = true;
|
|
if (row.tomb()) {
|
|
_read_context.cache()._tracker.on_row_tombstone_read();
|
|
}
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::add_to_buffer(range_tombstone_change&& rtc, source src) {
|
|
clogger.trace("csm {}: add_to_buffer({})", fmt::ptr(this), rtc);
|
|
if (auto rtc_opt = _rt_merger.apply(src, std::move(rtc))) {
|
|
do_add_to_buffer(std::move(*rtc_opt));
|
|
}
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::do_add_to_buffer(range_tombstone_change&& rtc) {
|
|
clogger.trace("csm {}: push({})", fmt::ptr(this), rtc);
|
|
position_in_partition::less_compare less(*_schema);
|
|
auto lower_bound_changed = less(_lower_bound, rtc.position());
|
|
_lower_bound = position_in_partition(rtc.position());
|
|
_lower_bound_changed = lower_bound_changed;
|
|
push_mutation_fragment(*_schema, _permit, std::move(rtc));
|
|
_read_context.cache()._tracker.on_range_tombstone_read();
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::add_range_tombstone_to_buffer(range_tombstone&& rt) {
|
|
position_in_partition::less_compare less(*_schema);
|
|
if (_queued_underlying_fragment && less(_queued_underlying_fragment->position(), rt.position())) {
|
|
add_to_buffer(*std::exchange(_queued_underlying_fragment, {}));
|
|
}
|
|
clogger.trace("csm {}: add_to_buffer({})", fmt::ptr(this), rt);
|
|
if (!less(_lower_bound, rt.position())) {
|
|
rt.set_start(_lower_bound);
|
|
}
|
|
flush_tombstones(rt.position());
|
|
_rt_gen.consume(std::move(rt));
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::maybe_add_to_cache(const range_tombstone_change& rtc) {
|
|
clogger.trace("csm {}: maybe_add_to_cache({})", fmt::ptr(this), rtc);
|
|
auto rt_opt = _rt_assembler.consume(*_schema, range_tombstone_change(rtc));
|
|
if (!rt_opt) {
|
|
return;
|
|
}
|
|
const auto& rt = *rt_opt;
|
|
if (can_populate()) {
|
|
clogger.trace("csm {}: maybe_add_to_cache({})", fmt::ptr(this), rt);
|
|
_lsa_manager.run_in_update_section_with_allocator([&] {
|
|
_snp->version()->partition().mutable_row_tombstones().apply_monotonically(
|
|
table_schema(), to_table_domain(rt));
|
|
});
|
|
} else {
|
|
_read_context.cache().on_mispopulate();
|
|
}
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::maybe_add_to_cache(const static_row& sr) {
|
|
if (can_populate()) {
|
|
clogger.trace("csm {}: populate({})", fmt::ptr(this), static_row::printer(*_schema, sr));
|
|
_read_context.cache().on_static_row_insert();
|
|
_lsa_manager.run_in_update_section_with_allocator([&] {
|
|
if (_read_context.digest_requested()) {
|
|
sr.cells().prepare_hash(*_schema, column_kind::static_column);
|
|
}
|
|
// Static row is the same under table and query schema
|
|
_snp->version()->partition().static_row().apply(table_schema(), column_kind::static_column, sr.cells());
|
|
});
|
|
} else {
|
|
_read_context.cache().on_mispopulate();
|
|
}
|
|
}
|
|
|
|
inline
|
|
void cache_flat_mutation_reader::maybe_set_static_row_continuous() {
|
|
if (can_populate()) {
|
|
clogger.trace("csm {}: set static row continuous", fmt::ptr(this));
|
|
_snp->version()->partition().set_static_row_continuous(true);
|
|
} else {
|
|
_read_context.cache().on_mispopulate();
|
|
}
|
|
}
|
|
|
|
inline
|
|
bool cache_flat_mutation_reader::can_populate() const {
|
|
return _snp->at_latest_version() && _read_context.cache().phase_of(_read_context.key()) == _read_context.phase();
|
|
}
|
|
|
|
} // namespace cache
|
|
|
|
// pass a reference to ctx to cache_flat_mutation_reader
|
|
// keeping its ownership at caller's.
|
|
inline flat_mutation_reader_v2 make_cache_flat_mutation_reader(schema_ptr s,
|
|
dht::decorated_key dk,
|
|
query::clustering_key_filter_ranges crr,
|
|
row_cache& cache,
|
|
cache::read_context& ctx,
|
|
partition_snapshot_ptr snp)
|
|
{
|
|
return make_flat_mutation_reader_v2<cache::cache_flat_mutation_reader>(
|
|
std::move(s), std::move(dk), std::move(crr), ctx, std::move(snp), cache);
|
|
}
|
|
|
|
// transfer ownership of ctx to cache_flat_mutation_reader
|
|
inline flat_mutation_reader_v2 make_cache_flat_mutation_reader(schema_ptr s,
|
|
dht::decorated_key dk,
|
|
query::clustering_key_filter_ranges crr,
|
|
row_cache& cache,
|
|
std::unique_ptr<cache::read_context> unique_ctx,
|
|
partition_snapshot_ptr snp)
|
|
{
|
|
return make_flat_mutation_reader_v2<cache::cache_flat_mutation_reader>(
|
|
std::move(s), std::move(dk), std::move(crr), std::move(unique_ctx), std::move(snp), cache);
|
|
}
|