Files
scylladb/cql3/selection/abstract_function_selector.cc
Michał Sala bb7edf3785 cql3: selection: detect if a selection represents count(*)
The way that this detection works is a bit clunky, but it does its job
given the simplest cases e.g. "SELECT COUNT(*) FROM ks.t". It fails when
there are multiple selectors, or when there is a column name specified
("SELECT COUNT(column_name) FROM ks.t").
2022-02-01 21:14:41 +01:00

94 lines
3.1 KiB
C++

/*
*/
/*
* Modified by ScyllaDB
* Copyright (C) 2015-present ScyllaDB
*/
/*
* SPDX-License-Identifier: (AGPL-3.0-or-later and Apache-2.0)
*/
#include "abstract_function_selector.hh"
#include "aggregate_function_selector.hh"
#include "scalar_function_selector.hh"
#include "to_string.hh"
#include "cql3/selection/selector_factories.hh"
#include "cql3/functions/abstract_function.hh"
namespace cql3 {
namespace selection {
bool abstract_function_selector::requires_thread() const {
return _requires_thread;
}
shared_ptr<selector::factory>
abstract_function_selector::new_factory(shared_ptr<functions::function> fun, shared_ptr<selector_factories> factories) {
if (fun->is_aggregate()) {
if (factories->does_aggregation()) {
throw exceptions::invalid_request_exception("aggregate functions cannot be used as arguments of aggregate functions");
}
} else {
if (factories->does_aggregation() && !factories->contains_only_aggregate_functions()) {
throw exceptions::invalid_request_exception(format("the {} function arguments must be either all aggregates or all none aggregates",
fun->name()));
}
}
struct fun_selector_factory : public factory {
shared_ptr<functions::function> _fun;
shared_ptr<selector_factories> _factories;
fun_selector_factory(shared_ptr<functions::function> fun,
shared_ptr<selector_factories> factories)
: _fun(std::move(fun)), _factories(std::move(factories)) {
}
virtual sstring column_name() const override {
return _fun->column_name(_factories->get_column_names());
}
virtual data_type get_return_type() const override {
return _fun->return_type();
}
virtual shared_ptr<selector> new_instance() const override {
using ret_type = shared_ptr<selector>;
return _fun->is_aggregate() ? ret_type(::make_shared<aggregate_function_selector>(_fun, _factories->new_instances()))
: ret_type(::make_shared<scalar_function_selector>(_fun, _factories->new_instances()));
}
virtual bool is_write_time_selector_factory() const override {
return _factories->contains_write_time_selector_factory();
}
virtual bool is_ttl_selector_factory() const override {
return _factories->contains_ttl_selector_factory();
}
virtual bool is_aggregate_selector_factory() const override {
return _fun->is_aggregate() || _factories->contains_only_aggregate_functions();
}
virtual bool is_count_selector_factory() const override {
auto p = dynamic_cast<functions::abstract_function*>(_fun.get());
if (!p) {
return false;
}
return p->name().name == "countRows";
}
};
return make_shared<fun_selector_factory>(std::move(fun), std::move(factories));
}
bool scalar_function_selector::requires_thread() const {
return fun()->requires_thread();
}
}
}