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ff94dfd8a714a405aaba4da2c44a109feee956c5
wsrep-lib/src/client_state.cpp
Teemu Ollakka ff94dfd8a7 Handle the possibility of client command that cannot return results 
This patch adds the possibility to have client commands that do not
return results from DBMS. While processing such commands we must be
able to preserve errors until the next interaction with client.
Specifically if the transaction is bf aborted while processing such
a non-returning command, then we have to keep the deadlock error until
the client issues a command that may return the error.
To handle such cases, client_state::before_command() now takes
parameter keep_command_error. The DBMS is supposed set
keep_command_error true to instruct wsrep-lib to preserve errors (if
any) until the next command which sets keep_command_error false.

Dealing with a case where current client command does not return result.

Work in progress.

Fix typo and add assertions in keep_command_error()

Make keep_command_error a parameter to before_commit()

Fix comment about keep_command_error

Handle keep_command_error with s_must_abort in wsrep_before_command()

Fix unit test
2020-11-27 11:17:39 +01:00

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/*
* Copyright (C) 2018-2019 Codership Oy <info@codership.com>
*
* This file is part of wsrep-lib.
*
* Wsrep-lib is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* Wsrep-lib is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with wsrep-lib. If not, see <https://www.gnu.org/licenses/>.
*/
#include "wsrep/client_state.hpp"
#include "wsrep/compiler.hpp"
#include "wsrep/logger.hpp"
#include <unistd.h> // usleep()
#include <sstream>
#include <iostream>
wsrep::provider& wsrep::client_state::provider() const
{
return server_state_.provider();
}
void wsrep::client_state::open(wsrep::client_id id)
{
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
assert(state_ == s_none);
assert(keep_command_error_ == false);
debug_log_state("open: enter");
owning_thread_id_ = wsrep::this_thread::get_id();
rollbacker_active_ = false;
sync_wait_gtid_ = wsrep::gtid::undefined();
last_written_gtid_ = wsrep::gtid::undefined();
state(lock, s_idle);
id_ = id;
debug_log_state("open: leave");
}
void wsrep::client_state::close()
{
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
debug_log_state("close: enter");
state(lock, s_quitting);
keep_command_error_ = false;
lock.unlock();
if (transaction_.active() &&
(mode_ != m_local ||
transaction_.state() != wsrep::transaction::s_prepared))
{
client_service_.bf_rollback();
transaction_.after_statement();
}
if (mode_ == m_local)
{
disable_streaming();
}
debug_log_state("close: leave");
}
void wsrep::client_state::cleanup()
{
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
debug_log_state("cleanup: enter");
state(lock, s_none);
debug_log_state("cleanup: leave");
}
void wsrep::client_state::override_error(enum wsrep::client_error error,
enum wsrep::provider::status status)
{
assert(wsrep::this_thread::get_id() == owning_thread_id_);
// Error state should not be cleared with success code without
// explicit reset_error() call.
assert(current_error_ == wsrep::e_success ||
error != wsrep::e_success);
current_error_ = error;
current_error_status_ = status;
}
int wsrep::client_state::before_command(bool keep_command_error)
{
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
debug_log_state("before_command: enter");
// If the state is s_exec, the processing thread has already grabbed
// control with wait_rollback_complete_and_acquire_ownership()
if (state_ != s_exec)
{
assert(state_ == s_idle);
do_wait_rollback_complete_and_acquire_ownership(lock);
assert(state_ == s_exec);
client_service_.store_globals();
}
else
{
// This thread must have acquired control by other means,
// for example via wait_rollback_complete_and_acquire_ownership().
assert(wsrep::this_thread::get_id() == owning_thread_id_);
}
keep_command_error_ = keep_command_error;
// If the transaction is active, it must be either executing,
// aborted as rolled back by rollbacker, or must_abort if the
// client thread gained control via
// wait_rollback_complete_and_acquire_ownership()
// just before BF abort happened.
assert(transaction_.active() == false ||
(transaction_.state() == wsrep::transaction::s_executing ||
transaction_.state() == wsrep::transaction::s_prepared ||
transaction_.state() == wsrep::transaction::s_aborted ||
transaction_.state() == wsrep::transaction::s_must_abort));
if (transaction_.active())
{
if (transaction_.state() == wsrep::transaction::s_must_abort ||
transaction_.state() == wsrep::transaction::s_aborted)
{
if (transaction_.is_xa())
{
// Client will rollback explicitly, return error.
debug_log_state("before_command: error");
return 1;
}
override_error(wsrep::e_deadlock_error);
if (transaction_.state() == wsrep::transaction::s_must_abort)
{
lock.unlock();
client_service_.bf_rollback();
lock.lock();
}
if (keep_command_error_)
{
// Keep the error for the next command
debug_log_state("before_command: keep error");
return 0;
}
// Clean up the transaction and return error.
lock.unlock();
(void)transaction_.after_statement();
lock.lock();
assert(transaction_.active() == false);
assert(transaction_.state() == wsrep::transaction::s_aborted);
assert(current_error() != wsrep::e_success);
debug_log_state("before_command: error");
return 1;
}
}
debug_log_state("before_command: success");
return 0;
}
void wsrep::client_state::after_command_before_result()
{
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
debug_log_state("after_command_before_result: enter");
assert(state() == s_exec);
if (transaction_.active() &&
transaction_.state() == wsrep::transaction::s_must_abort)
{
override_error(wsrep::e_deadlock_error);
lock.unlock();
client_service_.bf_rollback();
// If keep current error is set, the result will be propagated
// back to client with some future command, so keep the transaction
// open here so that error handling can happen in before_command()
// hook.
if (not keep_command_error_)
{
(void)transaction_.after_statement();
}
lock.lock();
assert(transaction_.state() == wsrep::transaction::s_aborted);
assert(current_error() != wsrep::e_success);
}
state(lock, s_result);
debug_log_state("after_command_before_result: leave");
}
void wsrep::client_state::after_command_after_result()
{
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
debug_log_state("after_command_after_result_enter");
assert(state() == s_result);
assert(transaction_.state() != wsrep::transaction::s_aborting);
if (transaction_.active() &&
transaction_.state() == wsrep::transaction::s_must_abort)
{
lock.unlock();
client_service_.bf_rollback();
lock.lock();
assert(transaction_.state() == wsrep::transaction::s_aborted);
override_error(wsrep::e_deadlock_error);
}
else if (transaction_.active() == false && not keep_command_error_)
{
current_error_ = wsrep::e_success;
current_error_status_ = wsrep::provider::success;
}
keep_command_error_ = false;
sync_wait_gtid_ = wsrep::gtid::undefined();
state(lock, s_idle);
debug_log_state("after_command_after_result: leave");
}
int wsrep::client_state::before_statement()
{
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
debug_log_state("before_statement: enter");
#if 0
/**
* @todo It might be beneficial to implement timed wait for
* server synced state.
*/
if (allow_dirty_reads_ == false &&
server_state_.state() != wsrep::server_state::s_synced)
{
return 1;
}
#endif // 0
if (transaction_.active() &&
transaction_.state() == wsrep::transaction::s_must_abort)
{
// Rollback and cleanup will happen in after_command_before_result()
debug_log_state("before_statement_error");
return 1;
}
debug_log_state("before_statement: success");
return 0;
}
int wsrep::client_state::after_statement()
{
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
debug_log_state("after_statement: enter");
assert(state() == s_exec);
assert(mode() == m_local);
if (transaction_.active() &&
transaction_.state() == wsrep::transaction::s_must_abort)
{
lock.unlock();
client_service_.bf_rollback();
lock.lock();
assert(transaction_.state() == wsrep::transaction::s_aborted);
// Error may be set already. For example, if fragment size
// exceeded the maximum size in certify_fragment(), then
// we already have wsrep::e_error_during_commit
if (current_error() == wsrep::e_success)
{
override_error(wsrep::e_deadlock_error);
}
}
lock.unlock();
(void)transaction_.after_statement();
if (current_error() == wsrep::e_deadlock_error)
{
if (mode_ == m_local)
{
debug_log_state("after_statement: may_retry");
return 1;
}
else
{
debug_log_state("after_statement: error");
return 1;
}
}
debug_log_state("after_statement: success");
return 0;
}
//////////////////////////////////////////////////////////////////////////////
// Rollbacker synchronization //
//////////////////////////////////////////////////////////////////////////////
void wsrep::client_state::sync_rollback_complete()
{
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
debug_log_state("sync_rollback_complete: enter");
assert(state_ == s_idle && mode_ == m_local &&
transaction_.state() == wsrep::transaction::s_aborted);
set_rollbacker_active(false);
cond_.notify_all();
debug_log_state("sync_rollback_complete: leave");
}
void wsrep::client_state::wait_rollback_complete_and_acquire_ownership()
{
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
debug_log_state("wait_rollback_complete_and_acquire_ownership: enter");
if (state_ == s_idle)
{
do_wait_rollback_complete_and_acquire_ownership(lock);
}
assert(state_ == s_exec);
debug_log_state("wait_rollback_complete_and_acquire_ownership: leave");
}
//////////////////////////////////////////////////////////////////////////////
// Streaming //
//////////////////////////////////////////////////////////////////////////////
void wsrep::client_state::streaming_params(
enum wsrep::streaming_context::fragment_unit fragment_unit,
size_t fragment_size)
{
assert(mode_ == m_local);
transaction_.streaming_context().params(fragment_unit, fragment_size);
}
int wsrep::client_state::enable_streaming(
enum wsrep::streaming_context::fragment_unit
fragment_unit,
size_t fragment_size)
{
assert(mode_ == m_local);
if (transaction_.is_streaming() &&
transaction_.streaming_context().fragment_unit() !=
fragment_unit)
{
wsrep::log_error()
<< "Changing fragment unit for active streaming transaction "
<< "not allowed";
return 1;
}
transaction_.streaming_context().enable(fragment_unit, fragment_size);
return 0;
}
void wsrep::client_state::disable_streaming()
{
assert(mode_ == m_local);
assert(state_ == s_exec || state_ == s_quitting);
transaction_.streaming_context().disable();
}
//////////////////////////////////////////////////////////////////////////////
// TOI //
//////////////////////////////////////////////////////////////////////////////
enum wsrep::provider::status
wsrep::client_state::poll_enter_toi(
wsrep::unique_lock<wsrep::mutex>& lock,
const wsrep::key_array& keys,
const wsrep::const_buffer& buffer,
wsrep::ws_meta& meta,
int flags,
std::chrono::time_point<wsrep::clock> wait_until,
bool& timed_out)
{
WSREP_LOG_DEBUG(debug_log_level(),
wsrep::log::debug_level_client_state,
"poll_enter_toi: "
<< flags
<< ","
<< wait_until.time_since_epoch().count());
enum wsrep::provider::status status;
timed_out = false;
wsrep::ws_meta poll_meta; // tmp var for polling, as enter_toi may clear meta arg on errors
do
{
lock.unlock();
poll_meta = meta;
status = provider().enter_toi(id_, keys, buffer, poll_meta, flags);
if (status != wsrep::provider::success &&
not poll_meta.gtid().is_undefined())
{
// Successfully entered TOI, but the provider reported failure.
// This may happen for example if certification fails.
// Leave TOI before proceeding.
if (provider().leave_toi(id_, wsrep::mutable_buffer()))
{
wsrep::log_warning()
<< "Failed to leave TOI after failure in "
<< "poll_enter_toi()";
}
poll_meta = wsrep::ws_meta();
}
if (status == wsrep::provider::error_certification_failed ||
status == wsrep::provider::error_connection_failed)
{
::usleep(300000);
}
lock.lock();
timed_out = !(wait_until.time_since_epoch().count() &&
wsrep::clock::now() < wait_until);
}
while ((status == wsrep::provider::error_certification_failed ||
status == wsrep::provider::error_connection_failed) &&
not timed_out &&
not client_service_.interrupted(lock));
meta = poll_meta;
return status;
}
void wsrep::client_state::enter_toi_common(
wsrep::unique_lock<wsrep::mutex>& lock)
{
assert(lock.owns_lock());
toi_mode_ = mode_;
mode(lock, m_toi);
}
int wsrep::client_state::enter_toi_local(const wsrep::key_array& keys,
const wsrep::const_buffer& buffer,
std::chrono::time_point<wsrep::clock> wait_until)
{
debug_log_state("enter_toi_local: enter");
assert(state_ == s_exec);
assert(mode_ == m_local);
int ret;
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
bool timed_out;
auto const status(poll_enter_toi(
lock, keys, buffer,
toi_meta_,
wsrep::provider::flag::start_transaction |
wsrep::provider::flag::commit,
wait_until,
timed_out));
switch (status)
{
case wsrep::provider::success:
{
enter_toi_common(lock);
ret = 0;
break;
}
case wsrep::provider::error_certification_failed:
override_error(e_deadlock_error, status);
ret = 1;
break;
default:
if (timed_out) {
override_error(e_timeout_error);
} else {
override_error(e_error_during_commit, status);
}
ret = 1;
break;
}
debug_log_state("enter_toi_local: leave");
return ret;
}
void wsrep::client_state::enter_toi_mode(const wsrep::ws_meta& ws_meta)
{
debug_log_state("enter_toi_mode: enter");
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
assert(mode_ == m_high_priority);
enter_toi_common(lock);
toi_meta_ = ws_meta;
debug_log_state("enter_toi_mode: leave");
}
void wsrep::client_state::leave_toi_common()
{
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
mode(lock, toi_mode_);
toi_mode_ = m_undefined;
if (toi_meta_.gtid().is_undefined() == false)
{
update_last_written_gtid(toi_meta_.gtid());
}
toi_meta_ = wsrep::ws_meta();
}
int wsrep::client_state::leave_toi_local(const wsrep::mutable_buffer& err)
{
debug_log_state("leave_toi_local: enter");
assert(toi_mode_ == m_local);
leave_toi_common();
debug_log_state("leave_toi_local: leave");
return (provider().leave_toi(id_, err) == provider::success ? 0 : 1);
}
void wsrep::client_state::leave_toi_mode()
{
debug_log_state("leave_toi_mode: enter");
assert(toi_mode_ == m_high_priority);
leave_toi_common();
debug_log_state("leave_toi_mode: leave");
}
///////////////////////////////////////////////////////////////////////////////
// RSU //
///////////////////////////////////////////////////////////////////////////////
int wsrep::client_state::begin_rsu(int timeout)
{
if (server_state_.desync())
{
wsrep::log_warning() << "Failed to desync server";
return 1;
}
if (server_state_.server_service().wait_committing_transactions(timeout))
{
wsrep::log_warning() << "RSU failed due to pending transactions";
server_state_.resync();
return 1;
}
wsrep::seqno pause_seqno(server_state_.pause());
if (pause_seqno.is_undefined())
{
wsrep::log_warning() << "Failed to pause provider";
server_state_.resync();
return 1;
}
wsrep::log_info() << "Provider paused at: " << pause_seqno;
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
toi_mode_ = mode_;
mode(lock, m_rsu);
return 0;
}
int wsrep::client_state::end_rsu()
{
int ret(0);
try
{
server_state_.resume();
server_state_.resync();
}
catch (const wsrep::runtime_error& e)
{
wsrep::log_warning() << "End RSU failed: " << e.what();
ret = 1;
}
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
mode(lock, toi_mode_);
return ret;
}
///////////////////////////////////////////////////////////////////////////////
// NBO //
///////////////////////////////////////////////////////////////////////////////
int wsrep::client_state::begin_nbo_phase_one(
const wsrep::key_array& keys,
const wsrep::const_buffer& buffer,
std::chrono::time_point<wsrep::clock> wait_until)
{
debug_log_state("begin_nbo_phase_one: enter");
debug_log_keys(keys);
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
assert(state_ == s_exec);
assert(mode_ == m_local);
assert(toi_mode_ == m_undefined);
int ret;
bool timed_out;
auto const status(poll_enter_toi(
lock, keys, buffer,
toi_meta_,
wsrep::provider::flag::start_transaction,
wait_until,
timed_out));
switch (status)
{
case wsrep::provider::success:
toi_mode_ = mode_;
mode(lock, m_nbo);
ret= 0;
break;
case wsrep::provider::error_certification_failed:
override_error(e_deadlock_error, status);
ret = 1;
break;
default:
if (timed_out) {
override_error(e_timeout_error);
} else {
override_error(e_error_during_commit, status);
}
ret = 1;
break;
}
debug_log_state("begin_nbo_phase_one: leave");
return ret;
}
int wsrep::client_state::end_nbo_phase_one(const wsrep::mutable_buffer& err)
{
debug_log_state("end_nbo_phase_one: enter");
assert(state_ == s_exec);
assert(mode_ == m_nbo);
assert(in_toi());
enum wsrep::provider::status status(provider().leave_toi(id_, err));
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
int ret;
switch (status)
{
case wsrep::provider::success:
ret = 0;
break;
default:
override_error(e_error_during_commit, status);
ret = 1;
break;
}
nbo_meta_ = toi_meta_;
toi_meta_ = wsrep::ws_meta();
toi_mode_ = m_undefined;
debug_log_state("end_nbo_phase_one: leave");
return ret;
}
int wsrep::client_state::enter_nbo_mode(const wsrep::ws_meta& ws_meta)
{
assert(state_ == s_exec);
assert(mode_ == m_local);
assert(toi_mode_ == m_undefined);
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
nbo_meta_ = ws_meta;
mode(lock, m_nbo);
return 0;
}
int wsrep::client_state::begin_nbo_phase_two(
const wsrep::key_array& keys,
std::chrono::time_point<wsrep::clock> wait_until)
{
debug_log_state("begin_nbo_phase_two: enter");
debug_log_keys(keys);
assert(state_ == s_exec);
assert(mode_ == m_nbo);
assert(toi_mode_ == m_undefined);
assert(!in_toi());
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
// Note: nbo_meta_ is passed to enter_toi() as it is
// an input param containing gtid of NBO begin.
// Output stored in nbo_meta_ is copied to toi_meta_ for
// phase two end.
bool timed_out;
enum wsrep::provider::status status(
poll_enter_toi(lock, keys,
wsrep::const_buffer(),
nbo_meta_,
wsrep::provider::flag::commit,
wait_until,
timed_out));
int ret;
switch (status)
{
case wsrep::provider::success:
ret= 0;
toi_meta_ = nbo_meta_;
toi_mode_ = m_local;
break;
case wsrep::provider::error_provider_failed:
override_error(e_interrupted_error, status);
ret= 1;
break;
default:
if (timed_out)
{
override_error(e_timeout_error, status);
}
else
{
override_error(e_error_during_commit, status);
}
ret= 1;
break;
}
// Failed to grab TOI for completing NBO in order. This means that
// the operation cannot be ended in total order, so we end the
// NBO mode and let the DBMS to deal with the error.
if (ret)
{
mode(lock, m_local);
nbo_meta_ = wsrep::ws_meta();
}
debug_log_state("begin_nbo_phase_two: leave");
return ret;
}
int wsrep::client_state::end_nbo_phase_two(const wsrep::mutable_buffer& err)
{
debug_log_state("end_nbo_phase_two: enter");
assert(state_ == s_exec);
assert(mode_ == m_nbo);
assert(toi_mode_ == m_local);
assert(in_toi());
enum wsrep::provider::status status(
provider().leave_toi(id_, err));
wsrep::unique_lock<wsrep::mutex> lock(mutex_);
int ret;
switch (status)
{
case wsrep::provider::success:
ret = 0;
break;
default:
override_error(e_error_during_commit, status);
ret = 1;
break;
}
toi_meta_ = wsrep::ws_meta();
toi_mode_ = m_undefined;
nbo_meta_ = wsrep::ws_meta();
mode(lock, m_local);
debug_log_state("end_nbo_phase_two: leave");
return ret;
}
///////////////////////////////////////////////////////////////////////////////
// Misc //
///////////////////////////////////////////////////////////////////////////////
int wsrep::client_state::sync_wait(int timeout)
{
std::pair<wsrep::gtid, enum wsrep::provider::status> result(
server_state_.causal_read(timeout));
int ret(1);
switch (result.second)
{
case wsrep::provider::success:
sync_wait_gtid_ = result.first;
ret = 0;
break;
case wsrep::provider::error_not_implemented:
override_error(wsrep::e_not_supported_error);
break;
default:
override_error(wsrep::e_timeout_error);
break;
}
return ret;
}
///////////////////////////////////////////////////////////////////////////////
// Private //
///////////////////////////////////////////////////////////////////////////////
void wsrep::client_state::do_acquire_ownership(
wsrep::unique_lock<wsrep::mutex>& lock WSREP_UNUSED)
{
assert(lock.owns_lock());
// Be strict about client state for clients in local mode. The
// owning_thread_id_ is used to detect bugs which are caused by
// more than one thread operating the client state at the time,
// for example thread handling the client session and background
// rollbacker.
assert(state_ == s_idle || mode_ != m_local);
owning_thread_id_ = wsrep::this_thread::get_id();
}
void wsrep::client_state::do_wait_rollback_complete_and_acquire_ownership(
wsrep::unique_lock<wsrep::mutex>& lock)
{
assert(lock.owns_lock());
assert(state_ == s_idle);
while (is_rollbacker_active())
{
cond_.wait(lock);
}
do_acquire_ownership(lock);
state(lock, s_exec);
}
void wsrep::client_state::update_last_written_gtid(const wsrep::gtid& gtid)
{
assert(last_written_gtid_.is_undefined() ||
(last_written_gtid_.id() == gtid.id() &&
!(last_written_gtid_.seqno() > gtid.seqno())));
last_written_gtid_ = gtid;
}
void wsrep::client_state::debug_log_state(const char* context) const
{
WSREP_LOG_DEBUG(debug_log_level(),
wsrep::log::debug_level_client_state,
context
<< "(" << id_.get()
<< "," << to_c_string(state_)
<< "," << to_c_string(mode_)
<< "," << wsrep::to_string(current_error_)
<< "," << current_error_status_
<< ",toi: " << toi_meta_.seqno()
<< ",nbo: " << nbo_meta_.seqno() << ")");
}
void wsrep::client_state::debug_log_keys(const wsrep::key_array& keys) const
{
for (size_t i(0); i < keys.size(); ++i)
{
WSREP_LOG_DEBUG(debug_log_level(),
wsrep::log::debug_level_client_state,
"TOI keys: "
<< " id: " << id_
<< "key: " << keys[i]);
}
}
void wsrep::client_state::state(
wsrep::unique_lock<wsrep::mutex>& lock WSREP_UNUSED,
enum wsrep::client_state::state state)
{
// Verify that the current thread has gained control to the
// connection by calling before_command()
assert(wsrep::this_thread::get_id() == owning_thread_id_);
assert(lock.owns_lock());
static const char allowed[state_max_][state_max_] =
{
/* none idle exec result quit */
{ 0, 1, 0, 0, 0}, /* none */
{ 0, 0, 1, 0, 1}, /* idle */
{ 0, 0, 0, 1, 0}, /* exec */
{ 0, 1, 0, 0, 0}, /* result */
{ 1, 0, 0, 0, 0} /* quit */
};
if (!allowed[state_][state])
{
wsrep::log_warning() << "client_state: Unallowed state transition: "
<< state_ << " -> " << state;
assert(0);
}
state_hist_.push_back(state_);
state_ = state;
if (state_hist_.size() > 10)
{
state_hist_.erase(state_hist_.begin());
}
}
void wsrep::client_state::mode(
wsrep::unique_lock<wsrep::mutex>& lock WSREP_UNUSED,
enum mode mode)
{
assert(lock.owns_lock());
static const char allowed[n_modes_][n_modes_] =
{ /* u l h t r n */
{ 0, 0, 0, 0, 0, 0 }, /* undefined */
{ 0, 0, 1, 1, 1, 1 }, /* local */
{ 0, 1, 0, 1, 0, 1 }, /* high prio */
{ 0, 1, 1, 0, 0, 0 }, /* toi */
{ 0, 1, 0, 0, 0, 0 }, /* rsu */
{ 0, 1, 1, 0, 0, 0 } /* nbo */
};
if (!allowed[mode_][mode])
{
wsrep::log_warning() << "client_state: Unallowed mode transition: "
<< mode_ << " -> " << mode;
assert(0);
}
mode_ = mode;
}
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