Files
scylladb/cql3/cql_statement.hh
Michał Jadwiszczak da82c5f0b0 cql3:statements: run service level statements on shard0 with raft guard
To migrate service levels to be raft managed, obtain `group0_guard` to
be able to pass it to service_level_controller's methods.

Using this mechanism also automatically provides retries in case of
concurrent group0 operation.
2024-03-21 23:14:57 +01:00

142 lines
4.2 KiB
C++

/*
* Copyright (C) 2014-present ScyllaDB
*
* Modified by ScyllaDB
*/
/*
* SPDX-License-Identifier: (AGPL-3.0-or-later and Apache-2.0)
*/
#pragma once
#include "timeout_config.hh"
#include "service/raft/raft_group0_client.hh"
namespace service {
class storage_proxy;
class query_state;
class client_state;
}
namespace cql_transport {
namespace messages {
class result_message;
}
}
namespace cql3 {
class query_processor;
class metadata;
seastar::shared_ptr<const metadata> make_empty_metadata();
class query_options;
// A vector of CQL warnings generated during execution of a statement.
using cql_warnings_vec = std::vector<sstring>;
class cql_statement {
timeout_config_selector _timeout_config_selector;
public:
// CQL statement text
seastar::sstring raw_cql_statement;
// Returns true for statements that needs guard to be taken before the execution
virtual bool needs_guard(query_processor& qp, service::query_state& state) const {
return false;
}
explicit cql_statement(timeout_config_selector timeout_selector) : _timeout_config_selector(timeout_selector) {}
virtual ~cql_statement()
{ }
timeout_config_selector get_timeout_config_selector() const { return _timeout_config_selector; }
virtual uint32_t get_bound_terms() const = 0;
/**
* Perform any access verification necessary for the statement.
*
* @param state the current client state
*/
virtual seastar::future<> check_access(query_processor& qp, const service::client_state& state) const = 0;
/**
* Perform additional validation required by the statement.
* To be overridden by subclasses if needed.
*
* @param state the current client state
*/
virtual void validate(query_processor& qp, const service::client_state& state) const {}
/**
* Execute the statement and return the resulting result or null if there is no result.
*
* In case of a failure, it must return an exceptional future. It must not use
* the result_message::exception to indicate failure.
*
* @param state the current query state
* @param options options for this query (consistency, variables, pageSize, ...)
*/
virtual seastar::future<seastar::shared_ptr<cql_transport::messages::result_message>>
execute(query_processor& qp, service::query_state& state, const query_options& options, std::optional<service::group0_guard> guard) const = 0;
/**
* Execute the statement and return the resulting result or null if there is no result.
*
* Unlike execute(), it is allowed to return a result_message::exception which contains
* an exception that needs to be explicitly handled.
*
* @param state the current query state
* @param options options for this query (consistency, variables, pageSize, ...)
*/
virtual seastar::future<seastar::shared_ptr<cql_transport::messages::result_message>>
execute_without_checking_exception_message(query_processor& qp, service::query_state& state, const query_options& options, std::optional<service::group0_guard> guard) const {
return execute(qp, state, options, std::move(guard));
}
virtual bool depends_on(std::string_view ks_name, std::optional<std::string_view> cf_name) const = 0;
virtual seastar::shared_ptr<const metadata> get_result_metadata() const = 0;
virtual bool is_conditional() const {
return false;
}
};
class cql_statement_no_metadata : public cql_statement {
public:
using cql_statement::cql_statement;
virtual seastar::shared_ptr<const metadata> get_result_metadata() const override {
return make_empty_metadata();
}
};
// Conditional modification statements and batches
// return a result set and have metadata, while same
// statements without conditions do not.
class cql_statement_opt_metadata : public cql_statement {
protected:
// Result set metadata, may be empty for simple updates and batches
seastar::shared_ptr<metadata> _metadata;
public:
using cql_statement::cql_statement;
virtual seastar::shared_ptr<const metadata> get_result_metadata() const override {
if (_metadata) {
return _metadata;
}
return make_empty_metadata();
}
};
}