Files
scylladb/cql3/statements/cas_request.cc
2025-10-09 12:28:10 +02:00

220 lines
9.5 KiB
C++

/*
* Copyright (C) 2019-present ScyllaDB
*
* Modified by ScyllaDB
*/
/*
* SPDX-License-Identifier: (LicenseRef-ScyllaDB-Source-Available-1.0 and Apache-2.0)
*/
#include "mutation/mutation.hh"
#include "modification_statement.hh"
#include "cas_request.hh"
#include <seastar/core/sleep.hh>
#include "cql3/result_set.hh"
#include "cql3/expr/evaluate.hh"
#include "cql3/expr/expr-utils.hh"
#include "transport/messages/result_message.hh"
#include "types/map.hh"
#include "service/storage_proxy.hh"
#include "cql3/query_processor.hh"
namespace cql3::statements {
using namespace std::chrono;
void cas_request::add_row_update(const modification_statement& stmt_arg,
std::vector<query::clustering_range> ranges_arg,
modification_statement::json_cache_opt json_cache_arg,
const query_options& options_arg) {
// TODO: reserve updates array for batches
_updates.emplace_back(cas_row_update{
.statement = stmt_arg,
.ranges = std::move(ranges_arg),
.json_cache = std::move(json_cache_arg),
.options = options_arg});
}
std::optional<mutation> cas_request::apply_updates(api::timestamp_type ts) const {
// We're working with a single partition, so there will be only one element
// in the vector. A vector is used since this is a conventional format
// to pass a mutation onward.
std::optional<mutation> mutation_set;
for (const cas_row_update& op: _updates) {
update_parameters params(_schema, op.options, ts, op.statement.get_time_to_live(op.options), _rows);
auto statement_mutations = op.statement.apply_updates(_key, op.ranges, params, op.json_cache);
// Append all mutations (in fact only one) to the consolidated one.
for (mutation& m : statement_mutations) {
if (mutation_set.has_value() == false) {
mutation_set.emplace(std::move(m));
} else {
mutation_set->apply(std::move(m));
}
}
}
return mutation_set;
}
lw_shared_ptr<query::read_command> cas_request::read_command(query_processor& qp) const {
column_set columns_to_read(_schema->all_columns_count());
std::vector<query::clustering_range> ranges;
for (const cas_row_update& op : _updates) {
if (op.statement.has_conditions() == false && op.statement.requires_read() == false) {
// No point in pre-fetching the old row if the statement doesn't check it in a CAS and
// doesn't use it to apply updates.
continue;
}
columns_to_read.union_with(op.statement.columns_to_read());
if (op.statement.has_only_static_column_conditions() && !op.statement.requires_read()) {
// If a statement has only static column conditions and doesn't have operations that
// require read, it doesn't matter what clustering key range to query - any partition
// row will do for the check.
continue;
}
ranges.reserve(op.ranges.size());
std::copy(op.ranges.begin(), op.ranges.end(), std::back_inserter(ranges));
}
uint64_t max_rows = query::partition_max_rows;
if (ranges.empty()) {
// With only a static condition, we still want to make the distinction between
// a non-existing partition and one that exists (has some live data) but has not
// static content. So we query the first live row of the partition.
ranges.emplace_back(query::clustering_range::make_open_ended_both_sides());
max_rows = 1;
} else {
// WARNING: clustering_range::deoverlap can return incorrect results - refer to scylladb#22817 and scylladb#21604
ranges = query::clustering_range::deoverlap(std::move(ranges), clustering_key::tri_compare(*_schema));
}
auto options = update_parameters::options;
options.set(query::partition_slice::option::always_return_static_content);
query::partition_slice ps(std::move(ranges), *_schema, columns_to_read, options);
ps.set_partition_row_limit(max_rows);
return make_lw_shared<query::read_command>(_schema->id(), _schema->version(), std::move(ps), qp.proxy().get_max_result_size(ps),
query::tombstone_limit(qp.proxy().get_tombstone_limit()));
}
bool cas_request::applies_to() const {
for (const cas_row_update& op: _updates) {
if (!op.statement.has_conditions()) {
continue;
}
// No need to check subsequent conditions as we have already failed the current one.
auto old_row = find_old_row(op).row;
if (!op.statement.applies_to(_rows.selection.get(), old_row, op.options)) {
return false;
}
}
return true;
}
std::optional<mutation> cas_request::apply(foreign_ptr<lw_shared_ptr<query::result>> qr,
const query::partition_slice& slice, api::timestamp_type ts, cdc::per_request_options&) {
_rows = update_parameters::build_prefetch_data(_schema, *qr, slice);
if (applies_to()) {
return apply_updates(ts);
} else {
return {};
}
}
cas_request::old_row cas_request::find_old_row(const cas_row_update& op) const {
static const clustering_key empty_ckey = clustering_key::make_empty();
if (_key.empty()) {
throw exceptions::invalid_request_exception("Empty partition key range");
}
const partition_key& pkey = _key.front().start()->value().key().value();
// We must ignore statement clustering column restriction when
// choosing a row to check the conditions. If there is no
// exact match, choose static row to check if the statement
// applies.
// For example, the following update must successfully apply (effectively
// turn into INSERT), because, although the table doesn't have any regular rows matching the
// statement clustering column restriction, the static row matches the statement condition:
// CREATE TABLE t(p int, c int, s int static, v int, PRIMARY KEY(p, c));
// INSERT INTO t(p, s) VALUES(1, 1);
// UPDATE t SET v=1 WHERE p=1 AND c=1 IF s=1;
if (op.ranges.empty()) {
throw exceptions::invalid_request_exception("Empty clustering range");
}
const clustering_key& ckey = op.ranges.front().start() ? op.ranges.front().start()->value() : empty_ckey;
auto row = _rows.find_row(pkey, ckey);
auto ckey_ptr = &ckey;
if (row == nullptr && !ckey.is_empty() &&
!op.statement.has_if_exist_condition() && !op.statement.has_if_not_exist_condition()) {
row = _rows.find_row(pkey, empty_ckey);
ckey_ptr = &empty_ckey;
}
if (!row) {
ckey_ptr = &empty_ckey;
}
return old_row{ckey_ptr, row};
}
seastar::shared_ptr<cql_transport::messages::result_message>
cas_request::build_cas_result_set(seastar::shared_ptr<cql3::metadata> metadata,
const column_set& columns,
bool is_applied) const {
const partition_key& pkey = _key.front().start()->value().key().value();
const clustering_key empty_ckey = clustering_key::make_empty();
auto result_set = std::make_unique<cql3::result_set>(metadata);
auto pkey_bytes = pkey.explode();
for (const cas_row_update& op: _updates) {
// Construct the result set row
std::vector<bytes_opt> rs_row;
rs_row.reserve(metadata->value_count());
rs_row.emplace_back(boolean_type->decompose(is_applied));
// Get old row from prefetched data for the row update
auto old_row = find_old_row(op);
if (!old_row.row) {
// In case there is no old row, leave all other columns null
// so that we can infer whether the update attempts to insert a
// non-existing row.
rs_row.resize(metadata->value_count());
result_set->add_row(std::move(rs_row));
continue;
}
auto ckey_bytes = old_row.ckey->explode();
auto eval_inputs = expr::evaluation_inputs{
.partition_key = pkey_bytes,
.clustering_key = ckey_bytes,
.static_and_regular_columns = old_row.row->cells,
.selection = _rows.selection.get(),
};
// Fill in the cells from prefetch data (old row) into the result set row
for (ordinal_column_id id = columns.find_first(); id != column_set::npos; id = columns.find_next(id)) {
auto& cdef = _schema->column_at(id);
auto val = expr::extract_column_value(&cdef, eval_inputs);
if (!val) {
rs_row.emplace_back(bytes_opt{});
continue;
}
const abstract_type& column_type = *cdef.type;
if (column_type.is_listlike() && column_type.is_multi_cell()) {
// List/sets are fetched as maps, but need to be stored as sets.
const listlike_collection_type_impl& list_type = static_cast<const listlike_collection_type_impl&>(column_type);
auto map_type_holder = map_type_impl::get_instance(list_type.name_comparator(), list_type.value_comparator(), list_type.is_multi_cell());
const map_type_impl& map_type = static_cast<const map_type_impl&>(*map_type_holder);
auto cell = map_type.deserialize(managed_bytes_view(*val));
rs_row.emplace_back(list_type.serialize_map(map_type, cell));
} else {
rs_row.emplace_back(to_bytes(*val));
}
}
result_set->add_row(std::move(rs_row));
}
cql3::result result(std::move(result_set));
return seastar::make_shared<cql_transport::messages::result_message::rows>(std::move(result));
}
} // end of namespace "cql3::statements"