#include "mariadb.h" #include "rpl_parallel.h" #include "slave.h" #include "rpl_mi.h" #include "sql_parse.h" #include "debug_sync.h" #include "sql_repl.h" #include "wsrep_mysqld.h" #ifdef WITH_WSREP #include "wsrep_trans_observer.h" #endif /* Code for optional parallel execution of replicated events on the slave. */ /* Maximum number of queued events to accumulate in a local free list, before moving them to the global free list. There is additional a limit of how much to accumulate based on opt_slave_parallel_max_queued. */ #define QEV_BATCH_FREE 200 struct rpl_parallel_thread_pool global_rpl_thread_pool; static void signal_error_to_sql_driver_thread(THD *thd, rpl_group_info *rgi, int err); static int rpt_handle_event(rpl_parallel_thread::queued_event *qev, struct rpl_parallel_thread *rpt) { int err; rpl_group_info *rgi= qev->rgi; Relay_log_info *rli= rgi->rli; THD *thd= rgi->thd; Log_event *ev; DBUG_ASSERT(qev->typ == rpl_parallel_thread::queued_event::QUEUED_EVENT); ev= qev->ev; #ifdef WITH_WSREP if (wsrep_before_statement(thd)) { WSREP_WARN("Parallel slave failed at wsrep_before_statement() hook"); return(1); } #endif /* WITH_WSREP */ thd->system_thread_info.rpl_sql_info->rpl_filter = rli->mi->rpl_filter; ev->thd= thd; strcpy(rgi->event_relay_log_name_buf, qev->event_relay_log_name); rgi->event_relay_log_name= rgi->event_relay_log_name_buf; rgi->event_relay_log_pos= qev->event_relay_log_pos; rgi->future_event_relay_log_pos= qev->future_event_relay_log_pos; strcpy(rgi->future_event_master_log_name, qev->future_event_master_log_name); if (!(ev->is_artificial_event() || ev->is_relay_log_event() || (ev->when == 0))) rgi->last_master_timestamp= ev->when + (time_t)ev->exec_time; err= apply_event_and_update_pos_for_parallel(ev, thd, rgi); rli->executed_entries++; #ifdef WITH_WSREP if (wsrep_after_statement(thd)) { WSREP_WARN("Parallel slave failed at wsrep_after_statement() hook"); err= 1; } #endif /* WITH_WSREP */ /* ToDo: error handling. */ return err; } static void handle_queued_pos_update(THD *thd, rpl_parallel_thread::queued_event *qev) { int cmp; Relay_log_info *rli; rpl_parallel_entry *e; /* Events that are not part of an event group, such as Format Description, Stop, GTID List and such, are executed directly in the driver SQL thread, to keep the relay log state up-to-date. But the associated position update is done here, in sync with other normal events as they are queued to worker threads. */ if ((thd->variables.option_bits & OPTION_BEGIN) && opt_using_transactions) return; /* Do not update position if an earlier event group caused an error abort. */ DBUG_ASSERT(qev->typ == rpl_parallel_thread::queued_event::QUEUED_POS_UPDATE); rli= qev->rgi->rli; e= qev->entry_for_queued; if (e->stop_on_error_sub_id < (uint64)ULONGLONG_MAX || (e->force_abort && !rli->stop_for_until)) return; mysql_mutex_lock(&rli->data_lock); cmp= compare_log_name(rli->group_relay_log_name, qev->event_relay_log_name); if (cmp < 0) { rli->group_relay_log_pos= qev->future_event_relay_log_pos; strmake_buf(rli->group_relay_log_name, qev->event_relay_log_name); } else if (cmp == 0 && rli->group_relay_log_pos < qev->future_event_relay_log_pos) rli->group_relay_log_pos= qev->future_event_relay_log_pos; cmp= compare_log_name(rli->group_master_log_name, qev->future_event_master_log_name); if (cmp < 0) { strcpy(rli->group_master_log_name, qev->future_event_master_log_name); rli->group_master_log_pos= qev->future_event_master_log_pos; } else if (cmp == 0 && rli->group_master_log_pos < qev->future_event_master_log_pos) rli->group_master_log_pos= qev->future_event_master_log_pos; mysql_mutex_unlock(&rli->data_lock); mysql_cond_broadcast(&rli->data_cond); } /* Wait for any pending deadlock kills. Since deadlock kills happen asynchronously, we need to be sure they will be completed before starting a new transaction. Otherwise the new transaction might suffer a spurious kill. */ static void wait_for_pending_deadlock_kill(THD *thd, rpl_group_info *rgi) { PSI_stage_info old_stage; mysql_mutex_lock(&thd->LOCK_wakeup_ready); thd->ENTER_COND(&thd->COND_wakeup_ready, &thd->LOCK_wakeup_ready, &stage_waiting_for_deadlock_kill, &old_stage); while (rgi->killed_for_retry == rpl_group_info::RETRY_KILL_PENDING) mysql_cond_wait(&thd->COND_wakeup_ready, &thd->LOCK_wakeup_ready); thd->EXIT_COND(&old_stage); } static void finish_event_group(rpl_parallel_thread *rpt, uint64 sub_id, rpl_parallel_entry *entry, rpl_group_info *rgi) { THD *thd= rpt->thd; wait_for_commit *wfc= &rgi->commit_orderer; int err; thd->get_stmt_da()->set_overwrite_status(true); /* Remove any left-over registration to wait for a prior commit to complete. Normally, such wait would already have been removed at this point by wait_for_prior_commit() called from within COMMIT processing. However, in case of MyISAM and no binlog, we might not have any commit processing, and so we need to do the wait here, before waking up any subsequent commits, to preserve correct order of event execution. Also, in the error case we might have skipped waiting and thus need to remove it explicitly. It is important in the non-error case to do a wait, not just an unregister. Because we might be last in a group-commit that is replicated in parallel, and the following event will then wait for us to complete and rely on this also ensuring that any other event in the group has completed. And in the error case, correct GCO lifetime relies on the fact that once the last event group in the GCO has executed wait_for_prior_commit(), all earlier event groups have also committed; this way no more mark_start_commit() calls can be made and it is safe to de-allocate the GCO. */ err= wfc->wait_for_prior_commit(thd); if (unlikely(err) && !rgi->worker_error) signal_error_to_sql_driver_thread(thd, rgi, err); thd->wait_for_commit_ptr= NULL; mysql_mutex_lock(&entry->LOCK_parallel_entry); /* We need to mark that this event group started its commit phase, in case we missed it before (otherwise we would deadlock the next event group that is waiting for this). In most cases (normal DML), it will be a no-op. */ rgi->mark_start_commit_no_lock(); if (entry->last_committed_sub_id < sub_id) { /* Record that this event group has finished (eg. transaction is committed, if transactional), so other event groups will no longer attempt to wait for us to commit. Once we have increased entry->last_committed_sub_id, no other threads will execute register_wait_for_prior_commit() against us. Thus, by doing one extra (usually redundant) wakeup_subsequent_commits() we can ensure that no register_wait_for_prior_commit() can ever happen without a subsequent wakeup_subsequent_commits() to wake it up. We can race here with the next transactions, but that is fine, as long as we check that we do not decrease last_committed_sub_id. If this commit is done, then any prior commits will also have been done and also no longer need waiting for. */ entry->last_committed_sub_id= sub_id; if (entry->need_sub_id_signal) mysql_cond_broadcast(&entry->COND_parallel_entry); /* Now free any GCOs in which all transactions have committed. */ group_commit_orderer *tmp_gco= rgi->gco; while (tmp_gco && (!tmp_gco->next_gco || tmp_gco->last_sub_id > sub_id || tmp_gco->next_gco->wait_count > entry->count_committing_event_groups)) { /* We must not free a GCO before the wait_count of the following GCO has been reached and wakeup has been sent. Otherwise we will lose the wakeup and hang (there were several such bugs in the past). The intention is that this is ensured already since we only free when the last event group in the GCO has committed (tmp_gco->last_sub_id <= sub_id). However, if we have a bug, we have extra check on next_gco->wait_count to hopefully avoid hanging; we have here an assertion in debug builds that this check does not in fact trigger. */ DBUG_ASSERT(!tmp_gco->next_gco || tmp_gco->last_sub_id > sub_id); tmp_gco= tmp_gco->prev_gco; } while (tmp_gco) { group_commit_orderer *prev_gco= tmp_gco->prev_gco; tmp_gco->next_gco->prev_gco= NULL; rpt->loc_free_gco(tmp_gco); tmp_gco= prev_gco; } } /* If this event group got error, then any following event groups that have not yet started should just skip their group, preparing for stop of the SQL driver thread. */ if (unlikely(rgi->worker_error) && entry->stop_on_error_sub_id == (uint64)ULONGLONG_MAX) entry->stop_on_error_sub_id= sub_id; mysql_mutex_unlock(&entry->LOCK_parallel_entry); #ifdef ENABLED_DEBUG_SYNC DBUG_EXECUTE_IF("hold_worker_on_schedule", { if (entry->stop_on_error_sub_id < (uint64)ULONGLONG_MAX) { debug_sync_set_action(thd, STRING_WITH_LEN("now SIGNAL continue_worker")); } }); DBUG_EXECUTE_IF("rpl_parallel_simulate_wait_at_retry", { if (rgi->current_gtid.seq_no == 1000) { DBUG_ASSERT(entry->stop_on_error_sub_id == sub_id); debug_sync_set_action(thd, STRING_WITH_LEN("now WAIT_FOR proceed_by_1000")); } }); #endif if (rgi->killed_for_retry == rpl_group_info::RETRY_KILL_PENDING) wait_for_pending_deadlock_kill(thd, rgi); thd->clear_error(); thd->reset_killed(); /* Would do thd->get_stmt_da()->set_overwrite_status(false) here, but reset_diagnostics_area() already does that. */ thd->get_stmt_da()->reset_diagnostics_area(); wfc->wakeup_subsequent_commits(rgi->worker_error); } static void signal_error_to_sql_driver_thread(THD *thd, rpl_group_info *rgi, int err) { rgi->worker_error= err; /* In case we get an error during commit, inform following transactions that we aborted our commit. */ rgi->unmark_start_commit(); rgi->cleanup_context(thd, true); rgi->rli->abort_slave= true; rgi->rli->stop_for_until= false; mysql_mutex_lock(rgi->rli->relay_log.get_log_lock()); rgi->rli->relay_log.signal_relay_log_update(); mysql_mutex_unlock(rgi->rli->relay_log.get_log_lock()); } static void unlock_or_exit_cond(THD *thd, mysql_mutex_t *lock, bool *did_enter_cond, PSI_stage_info *old_stage) { if (*did_enter_cond) { thd->EXIT_COND(old_stage); *did_enter_cond= false; } else mysql_mutex_unlock(lock); } static void register_wait_for_prior_event_group_commit(rpl_group_info *rgi, rpl_parallel_entry *entry) { mysql_mutex_assert_owner(&entry->LOCK_parallel_entry); if (rgi->wait_commit_sub_id > entry->last_committed_sub_id) { /* Register that the commit of this event group must wait for the commit of the previous event group to complete before it may complete itself, so that we preserve commit order. */ wait_for_commit *waitee= &rgi->wait_commit_group_info->commit_orderer; rgi->commit_orderer.register_wait_for_prior_commit(waitee); } } /* Do not start parallel execution of this event group until all prior groups have reached the commit phase that are not safe to run in parallel with. */ static bool do_gco_wait(rpl_group_info *rgi, group_commit_orderer *gco, bool *did_enter_cond, PSI_stage_info *old_stage) { THD *thd= rgi->thd; rpl_parallel_entry *entry= rgi->parallel_entry; uint64 wait_count; mysql_mutex_assert_owner(&entry->LOCK_parallel_entry); if (!gco->installed) { group_commit_orderer *prev_gco= gco->prev_gco; if (prev_gco) { prev_gco->last_sub_id= gco->prior_sub_id; prev_gco->next_gco= gco; } gco->installed= true; } wait_count= gco->wait_count; if (wait_count > entry->count_committing_event_groups) { DEBUG_SYNC(thd, "rpl_parallel_start_waiting_for_prior"); thd->ENTER_COND(&gco->COND_group_commit_orderer, &entry->LOCK_parallel_entry, &stage_waiting_for_prior_transaction_to_start_commit, old_stage); *did_enter_cond= true; thd->set_time_for_next_stage(); do { if (!rgi->worker_error && unlikely(thd->check_killed(1))) { DEBUG_SYNC(thd, "rpl_parallel_start_waiting_for_prior_killed"); thd->clear_error(); thd->get_stmt_da()->reset_diagnostics_area(); thd->send_kill_message(); slave_output_error_info(rgi, thd); signal_error_to_sql_driver_thread(thd, rgi, 1); /* Even though we were killed, we need to continue waiting for the prior event groups to signal that we can continue. Otherwise we mess up the accounting for ordering. However, now that we have marked the error, events will just be skipped rather than executed, and things will progress quickly towards stop. */ } mysql_cond_wait(&gco->COND_group_commit_orderer, &entry->LOCK_parallel_entry); } while (wait_count > entry->count_committing_event_groups); } if (entry->force_abort && wait_count > entry->stop_count) { /* We are stopping (STOP SLAVE), and this event group is beyond the point where we can safely stop. So return a flag that will cause us to skip, rather than execute, the following events. */ return true; } else return false; } static bool do_ftwrl_wait(rpl_group_info *rgi, bool *did_enter_cond, PSI_stage_info *old_stage) { THD *thd= rgi->thd; rpl_parallel_entry *entry= rgi->parallel_entry; uint64 sub_id= rgi->gtid_sub_id; bool aborted= false; DBUG_ENTER("do_ftwrl_wait"); mysql_mutex_assert_owner(&entry->LOCK_parallel_entry); /* If a FLUSH TABLES WITH READ LOCK (FTWRL) is pending, check if this transaction is later than transactions that have priority to complete before FTWRL. If so, wait here so that FTWRL can proceed and complete first. (entry->pause_sub_id is ULONGLONG_MAX if no FTWRL is pending, which makes this test false as required). */ if (unlikely(sub_id > entry->pause_sub_id)) { thd->ENTER_COND(&entry->COND_parallel_entry, &entry->LOCK_parallel_entry, &stage_waiting_for_ftwrl, old_stage); *did_enter_cond= true; thd->set_time_for_next_stage(); do { if (entry->force_abort || rgi->worker_error) { aborted= true; break; } if (unlikely(thd->check_killed())) { slave_output_error_info(rgi, thd); signal_error_to_sql_driver_thread(thd, rgi, 1); break; } mysql_cond_wait(&entry->COND_parallel_entry, &entry->LOCK_parallel_entry); } while (sub_id > entry->pause_sub_id); /* We do not call EXIT_COND() here, as this will be done later by our caller (since we set *did_enter_cond to true). */ } if (sub_id > entry->largest_started_sub_id) entry->largest_started_sub_id= sub_id; DBUG_RETURN(aborted); } static int pool_mark_busy(rpl_parallel_thread_pool *pool, THD *thd) { PSI_stage_info old_stage; int res= 0; /* Wait here while the queue is busy. This is done to make FLUSH TABLES WITH READ LOCK work correctly, without incuring extra locking penalties in normal operation. FLUSH TABLES WITH READ LOCK needs to lock threads in the thread pool, and for this we need to make sure the pool will not go away during the operation. The LOCK_rpl_thread_pool is not suitable for this. It is taken by release_thread() while holding LOCK_rpl_thread; so it must be released before locking any LOCK_rpl_thread lock, or a deadlock can occur. So we protect the infrequent operations of FLUSH TABLES WITH READ LOCK and pool size changes with this condition wait. */ DBUG_EXECUTE_IF("mark_busy_mdev_22370",my_sleep(1000000);); mysql_mutex_lock(&pool->LOCK_rpl_thread_pool); if (thd) { thd->ENTER_COND(&pool->COND_rpl_thread_pool, &pool->LOCK_rpl_thread_pool, &stage_waiting_for_rpl_thread_pool, &old_stage); thd->set_time_for_next_stage(); } while (pool->busy) { if (thd && unlikely(thd->check_killed())) { res= 1; break; } mysql_cond_wait(&pool->COND_rpl_thread_pool, &pool->LOCK_rpl_thread_pool); } if (!res) pool->busy= true; if (thd) thd->EXIT_COND(&old_stage); else mysql_mutex_unlock(&pool->LOCK_rpl_thread_pool); return res; } static void pool_mark_not_busy(rpl_parallel_thread_pool *pool) { mysql_mutex_lock(&pool->LOCK_rpl_thread_pool); DBUG_ASSERT(pool->busy); pool->busy= false; mysql_cond_broadcast(&pool->COND_rpl_thread_pool); mysql_mutex_unlock(&pool->LOCK_rpl_thread_pool); } void rpl_unpause_after_ftwrl(THD *thd) { uint32 i; rpl_parallel_thread_pool *pool= &global_rpl_thread_pool; DBUG_ENTER("rpl_unpause_after_ftwrl"); DBUG_ASSERT(pool->busy); for (i= 0; i < pool->count; ++i) { rpl_parallel_entry *e; rpl_parallel_thread *rpt= pool->threads[i]; mysql_mutex_lock(&rpt->LOCK_rpl_thread); if (!rpt->current_owner) { mysql_mutex_unlock(&rpt->LOCK_rpl_thread); continue; } e= rpt->current_entry; mysql_mutex_lock(&e->LOCK_parallel_entry); rpt->pause_for_ftwrl = false; mysql_mutex_unlock(&rpt->LOCK_rpl_thread); /* Do not change pause_sub_id if force_abort is set. force_abort is set in case of STOP SLAVE. Reason: If pause_sub_id is not changed and force_abort_is set, any parallel slave thread waiting in do_ftwrl_wait() will on wakeup return from do_ftwrl_wait() with 1. This will set skip_event_group to 1 in handle_rpl_parallel_thread() and the parallel thread will abort at once. If pause_sub_id is changed, the code in handle_rpl_parallel_thread() would continue to execute the transaction in the queue, which would cause some transactions to be lost. */ if (!e->force_abort) e->pause_sub_id= (uint64)ULONGLONG_MAX; mysql_cond_broadcast(&e->COND_parallel_entry); mysql_mutex_unlock(&e->LOCK_parallel_entry); } pool_mark_not_busy(pool); DBUG_VOID_RETURN; } /* . Note: in case of error return, rpl_unpause_after_ftwrl() must _not_ be called. */ int rpl_pause_for_ftwrl(THD *thd) { uint32 i; rpl_parallel_thread_pool *pool= &global_rpl_thread_pool; int err; DBUG_ENTER("rpl_pause_for_ftwrl"); /* While the count_pending_pause_for_ftwrl counter is non-zero, the pool cannot be shutdown/resized, so threads are guaranteed to not disappear. This is required to safely be able to access the individual threads below. (We cannot lock an individual thread while holding LOCK_rpl_thread_pool, as this can deadlock against release_thread()). */ if ((err= pool_mark_busy(pool, thd))) DBUG_RETURN(err); for (i= 0; i < pool->count; ++i) { PSI_stage_info old_stage; rpl_parallel_entry *e; rpl_parallel_thread *rpt= pool->threads[i]; mysql_mutex_lock(&rpt->LOCK_rpl_thread); if (!rpt->current_owner) { mysql_mutex_unlock(&rpt->LOCK_rpl_thread); continue; } e= rpt->current_entry; mysql_mutex_lock(&e->LOCK_parallel_entry); /* Setting the rpt->pause_for_ftwrl flag makes sure that the thread will not de-allocate itself until signalled to do so by rpl_unpause_after_ftwrl(). */ rpt->pause_for_ftwrl = true; mysql_mutex_unlock(&rpt->LOCK_rpl_thread); ++e->need_sub_id_signal; if (e->pause_sub_id == (uint64)ULONGLONG_MAX) e->pause_sub_id= e->largest_started_sub_id; thd->ENTER_COND(&e->COND_parallel_entry, &e->LOCK_parallel_entry, &stage_waiting_for_ftwrl_threads_to_pause, &old_stage); thd->set_time_for_next_stage(); while (e->pause_sub_id < (uint64)ULONGLONG_MAX && e->last_committed_sub_id < e->pause_sub_id && !err) { if (unlikely(thd->check_killed())) { err= 1; break; } mysql_cond_wait(&e->COND_parallel_entry, &e->LOCK_parallel_entry); }; --e->need_sub_id_signal; thd->EXIT_COND(&old_stage); if (err) break; } if (err) rpl_unpause_after_ftwrl(thd); DBUG_RETURN(err); } #ifndef DBUG_OFF static int dbug_simulate_tmp_error(rpl_group_info *rgi, THD *thd) { if (rgi->current_gtid.domain_id == 0 && rgi->current_gtid.seq_no == 100 && rgi->retry_event_count == 4) { thd->clear_error(); thd->get_stmt_da()->reset_diagnostics_area(); my_error(ER_LOCK_DEADLOCK, MYF(0)); return 1; } return 0; } #endif /* If we detect a deadlock due to eg. storage engine locks that conflict with the fixed commit order, then the later transaction will be killed asynchroneously to allow the former to complete its commit. In this case, we convert the 'killed' error into a deadlock error, and retry the later transaction. If we are doing optimistic parallel apply of transactions not known to be safe, we convert any error to a deadlock error, but then at retry we will wait for prior transactions to commit first, so that the retries can be done non-speculative. */ static void convert_kill_to_deadlock_error(rpl_group_info *rgi) { THD *thd= rgi->thd; int err_code; if (!thd->get_stmt_da()->is_error()) return; err_code= thd->get_stmt_da()->sql_errno(); if ((rgi->speculation == rpl_group_info::SPECULATE_OPTIMISTIC && err_code != ER_PRIOR_COMMIT_FAILED) || ((err_code == ER_QUERY_INTERRUPTED || err_code == ER_CONNECTION_KILLED) && rgi->killed_for_retry)) { thd->clear_error(); my_error(ER_LOCK_DEADLOCK, MYF(0)); thd->reset_killed(); } } /* Check if an event marks the end of an event group. Returns non-zero if so, zero otherwise. In addition, returns 1 if the group is committing, 2 if it is rolling back. */ static int is_group_ending(Log_event *ev, Log_event_type event_type) { if (event_type == XID_EVENT || event_type == XA_PREPARE_LOG_EVENT) return 1; if (event_type == QUERY_EVENT) // COMMIT/ROLLBACK are never compressed { Query_log_event *qev = (Query_log_event *)ev; if (qev->is_commit() || !strncmp(qev->query, STRING_WITH_LEN("XA COMMIT")) || !strncmp(qev->query, STRING_WITH_LEN("XA ROLLBACK"))) return 1; if (qev->is_rollback()) return 2; } return 0; } static int retry_event_group(rpl_group_info *rgi, rpl_parallel_thread *rpt, rpl_parallel_thread::queued_event *orig_qev) { IO_CACHE rlog; LOG_INFO linfo; File fd= (File)-1; const char *errmsg; inuse_relaylog *ir= rgi->relay_log; uint64 event_count; uint64 events_to_execute= rgi->retry_event_count; Relay_log_info *rli= rgi->rli; int err; ulonglong cur_offset, old_offset; char log_name[FN_REFLEN]; THD *thd= rgi->thd; rpl_parallel_entry *entry= rgi->parallel_entry; ulong retries= 0; Format_description_log_event *description_event= NULL; do_retry: event_count= 0; err= 0; errmsg= NULL; /* If we already started committing before getting the deadlock (or other error) that caused us to need to retry, we have already signalled subsequent transactions that we have started committing. This is potentially a problem, as now we will rollback, and if subsequent transactions would start to execute now, they could see an unexpected state of the database and get eg. key not found or duplicate key error. However, to get a deadlock in the first place, there must have been another earlier transaction that is waiting for us. Thus that other transaction has _not_ yet started to commit, and any subsequent transactions will still be waiting at this point. So here, we decrement back the count of transactions that started committing (if we already incremented it), undoing the effect of an earlier mark_start_commit(). Then later, when the retry succeeds and we commit again, we can do a new mark_start_commit() and eventually wake up subsequent transactions at the proper time. We need to do the unmark before the rollback, to be sure that the transaction we deadlocked with will not signal that it started to commit until after the unmark. */ DBUG_EXECUTE_IF("inject_mdev8302", { my_sleep(20000);}); rgi->unmark_start_commit(); DEBUG_SYNC(thd, "rpl_parallel_retry_after_unmark"); /* We might get the deadlock error that causes the retry during commit, while sitting in wait_for_prior_commit(). If this happens, we will have a pending error in the wait_for_commit object. So clear this by unregistering (and later re-registering) the wait. */ if(thd->wait_for_commit_ptr) thd->wait_for_commit_ptr->unregister_wait_for_prior_commit(); DBUG_EXECUTE_IF("inject_mdev8031", { /* Simulate that we get deadlock killed at this exact point. */ rgi->killed_for_retry= rpl_group_info::RETRY_KILL_KILLED; thd->set_killed(KILL_CONNECTION); }); #ifdef ENABLED_DEBUG_SYNC DBUG_EXECUTE_IF("rpl_parallel_simulate_wait_at_retry", { if (rgi->current_gtid.seq_no == 1001) { debug_sync_set_action(thd, STRING_WITH_LEN("rpl_parallel_simulate_wait_at_retry WAIT_FOR proceed_by_1001")); } DEBUG_SYNC(thd, "rpl_parallel_simulate_wait_at_retry"); }); #endif rgi->cleanup_context(thd, 1); wait_for_pending_deadlock_kill(thd, rgi); thd->reset_killed(); thd->clear_error(); rgi->killed_for_retry = rpl_group_info::RETRY_KILL_NONE; /* If we retry due to a deadlock kill that occurred during the commit step, we might have already updated (but not committed) an update of table mysql.gtid_slave_pos, and cleared the gtid_pending flag. Now we have rolled back any such update, so we must set the gtid_pending flag back to true so that we will do a new update when/if we succeed with the retry. */ rgi->gtid_pending= true; mysql_mutex_lock(&rli->data_lock); ++rli->retried_trans; statistic_increment(slave_retried_transactions, LOCK_status); mysql_mutex_unlock(&rli->data_lock); for (;;) { mysql_mutex_lock(&entry->LOCK_parallel_entry); if (entry->stop_on_error_sub_id == (uint64) ULONGLONG_MAX || #ifndef DBUG_OFF (DBUG_EVALUATE_IF("simulate_mdev_12746", 1, 0)) || #endif rgi->gtid_sub_id < entry->stop_on_error_sub_id) { register_wait_for_prior_event_group_commit(rgi, entry); } else { /* A failure of a preceding "parent" transaction may not be seen by the current one through its own worker_error. Such induced error gets set by ourselves now. */ err= rgi->worker_error= 1; my_error(ER_PRIOR_COMMIT_FAILED, MYF(0)); mysql_mutex_unlock(&entry->LOCK_parallel_entry); goto err; } mysql_mutex_unlock(&entry->LOCK_parallel_entry); /* Let us wait for all prior transactions to complete before trying again. This way, we avoid repeatedly conflicting with and getting deadlock killed by the same earlier transaction. */ if (!(err= thd->wait_for_prior_commit())) { rgi->speculation = rpl_group_info::SPECULATE_WAIT; break; } convert_kill_to_deadlock_error(rgi); if (!has_temporary_error(thd)) goto err; /* If we get a temporary error such as a deadlock kill, we can safely ignore it, as we already rolled back. But we still want to retry the wait for the prior transaction to complete its commit. */ thd->clear_error(); thd->reset_killed(); if(thd->wait_for_commit_ptr) thd->wait_for_commit_ptr->unregister_wait_for_prior_commit(); DBUG_EXECUTE_IF("inject_mdev8031", { /* Inject a small sleep to give prior transaction a chance to commit. */ my_sleep(100000); }); } /* Let us clear any lingering deadlock kill one more time, here after wait_for_prior_commit() has completed. This should rule out any possibility of an old deadlock kill lingering on beyond this point. */ thd->reset_killed(); strmake_buf(log_name, ir->name); if ((fd= open_binlog(&rlog, log_name, &errmsg)) <0) { err= 1; goto err; } cur_offset= rgi->retry_start_offset; delete description_event; description_event= read_relay_log_description_event(&rlog, cur_offset, &errmsg); if (!description_event) { err= 1; goto err; } DBUG_EXECUTE_IF("inject_mdev8031", { /* Simulate pending KILL caught in read_relay_log_description_event(). */ if (unlikely(thd->check_killed())) { err= 1; goto err; } }); my_b_seek(&rlog, cur_offset); do { Log_event_type event_type; Log_event *ev; rpl_parallel_thread::queued_event *qev; /* The loop is here so we can try again the next relay log file on EOF. */ for (;;) { old_offset= cur_offset; ev= Log_event::read_log_event(&rlog, description_event, opt_slave_sql_verify_checksum); cur_offset= my_b_tell(&rlog); if (ev) break; if (unlikely(rlog.error < 0)) { errmsg= "slave SQL thread aborted because of I/O error"; err= 1; goto check_retry; } if (unlikely(rlog.error > 0)) { sql_print_error("Slave SQL thread: I/O error reading " "event(errno: %d cur_log->error: %d)", my_errno, rlog.error); errmsg= "Aborting slave SQL thread because of partial event read"; err= 1; goto err; } /* EOF. Move to the next relay log. */ end_io_cache(&rlog); mysql_file_close(fd, MYF(MY_WME)); fd= (File)-1; /* Find the next relay log file. */ if((err= rli->relay_log.find_log_pos(&linfo, log_name, 1)) || (err= rli->relay_log.find_next_log(&linfo, 1))) { char buff[22]; sql_print_error("next log error: %d offset: %s log: %s", err, llstr(linfo.index_file_offset, buff), log_name); goto err; } strmake_buf(log_name ,linfo.log_file_name); DBUG_EXECUTE_IF("inject_retry_event_group_open_binlog_kill", { if (retries < 2) { /* Simulate that we get deadlock killed during open_binlog(). */ thd->reset_for_next_command(); rgi->killed_for_retry= rpl_group_info::RETRY_KILL_KILLED; thd->set_killed(KILL_CONNECTION); thd->send_kill_message(); fd= (File)-1; err= 1; goto check_retry; } }); if ((fd= open_binlog(&rlog, log_name, &errmsg)) <0) { err= 1; goto check_retry; } description_event->reset_crypto(); /* Loop to try again on the new log file. */ } event_type= ev->get_type_code(); if (event_type == FORMAT_DESCRIPTION_EVENT) { Format_description_log_event *newde= (Format_description_log_event*)ev; newde->copy_crypto_data(description_event); delete description_event; description_event= newde; continue; } else if (event_type == START_ENCRYPTION_EVENT) { description_event->start_decryption((Start_encryption_log_event*)ev); delete ev; continue; } else if (!Log_event::is_group_event(event_type)) { delete ev; continue; } ev->thd= thd; mysql_mutex_lock(&rpt->LOCK_rpl_thread); qev= rpt->retry_get_qev(ev, orig_qev, log_name, old_offset, cur_offset - old_offset); mysql_mutex_unlock(&rpt->LOCK_rpl_thread); if (!qev) { delete ev; my_error(ER_OUT_OF_RESOURCES, MYF(0)); err= 1; goto err; } if (is_group_ending(ev, event_type) == 1) rgi->mark_start_commit(); err= rpt_handle_event(qev, rpt); ++event_count; mysql_mutex_lock(&rpt->LOCK_rpl_thread); rpt->free_qev(qev); mysql_mutex_unlock(&rpt->LOCK_rpl_thread); delete_or_keep_event_post_apply(rgi, event_type, ev); DBUG_EXECUTE_IF("rpl_parallel_simulate_double_temp_err_gtid_0_x_100", if (retries == 0) err= dbug_simulate_tmp_error(rgi, thd);); DBUG_EXECUTE_IF("rpl_parallel_simulate_infinite_temp_err_gtid_0_x_100", err= dbug_simulate_tmp_error(rgi, thd);); if (!err) continue; check_retry: convert_kill_to_deadlock_error(rgi); if (has_temporary_error(thd)) { ++retries; if (retries < slave_trans_retries) { if (fd >= 0) { end_io_cache(&rlog); mysql_file_close(fd, MYF(MY_WME)); fd= (File)-1; } goto do_retry; } sql_print_error("Slave worker thread retried transaction %lu time(s) " "in vain, giving up. Consider raising the value of " "the slave_transaction_retries variable.", slave_trans_retries); } goto err; } while (event_count < events_to_execute); err: if (description_event) delete description_event; if (fd >= 0) { end_io_cache(&rlog); mysql_file_close(fd, MYF(MY_WME)); } if (errmsg) sql_print_error("Error reading relay log event: %s", errmsg); return err; } pthread_handler_t handle_rpl_parallel_thread(void *arg) { THD *thd; PSI_stage_info old_stage; struct rpl_parallel_thread::queued_event *events; bool group_standalone= true; bool in_event_group= false; bool skip_event_group= false; rpl_group_info *group_rgi= NULL; group_commit_orderer *gco; uint64 event_gtid_sub_id= 0; rpl_sql_thread_info sql_info(NULL); int err; struct rpl_parallel_thread *rpt= (struct rpl_parallel_thread *)arg; my_thread_init(); thd = new THD(next_thread_id()); thd->thread_stack = (char*)&thd; server_threads.insert(thd); set_current_thd(thd); pthread_detach_this_thread(); thd->store_globals(); thd->init_for_queries(); thd->variables.binlog_annotate_row_events= 0; init_thr_lock(); thd->system_thread= SYSTEM_THREAD_SLAVE_SQL; thd->security_ctx->skip_grants(); thd->variables.max_allowed_packet= slave_max_allowed_packet; /* Ensure that slave can exeute any alter table it gets from master */ thd->variables.alter_algorithm= (ulong) Alter_info::ALTER_TABLE_ALGORITHM_DEFAULT; thd->slave_thread= 1; set_slave_thread_options(thd); thd->client_capabilities = CLIENT_LOCAL_FILES; thd->net.reading_or_writing= 0; thd_proc_info(thd, "Waiting for work from main SQL threads"); thd->variables.lock_wait_timeout= LONG_TIMEOUT; thd->system_thread_info.rpl_sql_info= &sql_info; /* We need to use (at least) REPEATABLE READ isolation level. Otherwise speculative parallel apply can run out-of-order and give wrong results for statement-based replication. */ thd->variables.tx_isolation= ISO_REPEATABLE_READ; mysql_mutex_lock(&rpt->LOCK_rpl_thread); rpt->thd= thd; while (rpt->delay_start) mysql_cond_wait(&rpt->COND_rpl_thread, &rpt->LOCK_rpl_thread); rpt->running= true; mysql_cond_signal(&rpt->COND_rpl_thread); thd->set_command(COM_SLAVE_WORKER); #ifdef WITH_WSREP wsrep_open(thd); if (wsrep_before_command(thd)) { WSREP_WARN("Parallel slave failed at wsrep_before_command() hook"); rpt->stop = true; } #endif /* WITH_WSREP */ while (!rpt->stop) { uint wait_count= 0; rpl_parallel_thread::queued_event *qev, *next_qev; thd->ENTER_COND(&rpt->COND_rpl_thread, &rpt->LOCK_rpl_thread, &stage_waiting_for_work_from_sql_thread, &old_stage); /* There are 4 cases that should cause us to wake up: - Events have been queued for us to handle. - We have an owner, but no events and not inside event group -> we need to release ourself to the thread pool - SQL thread is stopping, and we have an owner but no events, and we are inside an event group; no more events will be queued to us, so we need to abort the group (force_abort==1). - Thread pool shutdown (rpt->stop==1). */ while (!( (events= rpt->event_queue) || (rpt->current_owner && !in_event_group) || (rpt->current_owner && group_rgi->parallel_entry->force_abort) || rpt->stop)) { if (!wait_count++) thd->set_time_for_next_stage(); mysql_cond_wait(&rpt->COND_rpl_thread, &rpt->LOCK_rpl_thread); } rpt->dequeue1(events); thd->EXIT_COND(&old_stage); more_events: for (qev= events; qev; qev= next_qev) { Log_event_type event_type; rpl_group_info *rgi= qev->rgi; rpl_parallel_entry *entry= rgi->parallel_entry; bool end_of_group; int group_ending; next_qev= qev->next; if (qev->typ == rpl_parallel_thread::queued_event::QUEUED_POS_UPDATE) { handle_queued_pos_update(thd, qev); rpt->loc_free_qev(qev); continue; } else if (qev->typ == rpl_parallel_thread::queued_event::QUEUED_MASTER_RESTART) { if (in_event_group) { /* Master restarted (crashed) in the middle of an event group. So we need to roll back and discard that event group. */ group_rgi->cleanup_context(thd, 1); in_event_group= false; finish_event_group(rpt, group_rgi->gtid_sub_id, qev->entry_for_queued, group_rgi); rpt->loc_free_rgi(group_rgi); thd->rgi_slave= group_rgi= NULL; } rpt->loc_free_qev(qev); continue; } DBUG_ASSERT(qev->typ==rpl_parallel_thread::queued_event::QUEUED_EVENT); thd->rgi_slave= rgi; gco= rgi->gco; /* Handle a new event group, which will be initiated by a GTID event. */ if ((event_type= qev->ev->get_type_code()) == GTID_EVENT) { bool did_enter_cond= false; PSI_stage_info old_stage; #ifdef ENABLED_DEBUG_SYNC DBUG_EXECUTE_IF("hold_worker_on_schedule", { if (rgi->current_gtid.domain_id == 0 && rgi->current_gtid.seq_no == 100) { debug_sync_set_action(thd, STRING_WITH_LEN("now SIGNAL reached_pause WAIT_FOR continue_worker")); } }); DBUG_EXECUTE_IF("rpl_parallel_scheduled_gtid_0_x_100", { if (rgi->current_gtid.domain_id == 0 && rgi->current_gtid.seq_no == 100) { debug_sync_set_action(thd, STRING_WITH_LEN("now SIGNAL scheduled_gtid_0_x_100")); } }); #endif if(unlikely(thd->wait_for_commit_ptr) && group_rgi != NULL) { /* This indicates that we get a new GTID event in the middle of a not completed event group. This is corrupt binlog (the master will never write such binlog), so it does not happen unless someone tries to inject wrong crafted binlog, but let us still try to handle it somewhat nicely. */ group_rgi->cleanup_context(thd, true); finish_event_group(rpt, group_rgi->gtid_sub_id, group_rgi->parallel_entry, group_rgi); rpt->loc_free_rgi(group_rgi); } thd->tx_isolation= (enum_tx_isolation)thd->variables.tx_isolation; in_event_group= true; /* If the standalone flag is set, then this event group consists of a single statement (possibly preceeded by some Intvar_log_event and similar), without any terminating COMMIT/ROLLBACK/XID. */ group_standalone= (0 != (static_cast(qev->ev)->flags2 & Gtid_log_event::FL_STANDALONE)); event_gtid_sub_id= rgi->gtid_sub_id; rgi->thd= thd; mysql_mutex_lock(&entry->LOCK_parallel_entry); skip_event_group= do_gco_wait(rgi, gco, &did_enter_cond, &old_stage); if (unlikely(entry->stop_on_error_sub_id <= rgi->wait_commit_sub_id)) { skip_event_group= true; rgi->worker_error= 1; } if (likely(!skip_event_group)) skip_event_group= do_ftwrl_wait(rgi, &did_enter_cond, &old_stage); /* Register ourself to wait for the previous commit, if we need to do such registration _and_ that previous commit has not already occurred. */ register_wait_for_prior_event_group_commit(rgi, entry); unlock_or_exit_cond(thd, &entry->LOCK_parallel_entry, &did_enter_cond, &old_stage); thd->wait_for_commit_ptr= &rgi->commit_orderer; if (opt_gtid_ignore_duplicates && rgi->rli->mi->using_gtid != Master_info::USE_GTID_NO) { int res= rpl_global_gtid_slave_state->check_duplicate_gtid(&rgi->current_gtid, rgi); if (res < 0) { /* Error. */ slave_output_error_info(rgi, thd); signal_error_to_sql_driver_thread(thd, rgi, 1); } else if (!res) { /* GTID already applied by another master connection, skip. */ skip_event_group= true; } else { /* We have to apply the event. */ } } /* If we are optimistically running transactions in parallel, but this particular event group should not run in parallel with what came before, then wait now for the prior transaction to complete its commit. */ if (rgi->speculation == rpl_group_info::SPECULATE_WAIT && (err= thd->wait_for_prior_commit())) { slave_output_error_info(rgi, thd); signal_error_to_sql_driver_thread(thd, rgi, 1); } } group_rgi= rgi; group_ending= is_group_ending(qev->ev, event_type); /* We do not unmark_start_commit() here in case of an explicit ROLLBACK statement. Such events should be very rare, there is no real reason to try to group commit them - on the contrary, it seems best to avoid running them in parallel with following group commits, as with ROLLBACK events we are already deep in dangerous corner cases with mix of transactional and non-transactional tables or the like. And avoiding the mark_start_commit() here allows us to keep an assertion in ha_rollback_trans() that we do not rollback after doing mark_start_commit(). */ if (group_ending == 1 && likely(!rgi->worker_error)) { /* Do an extra check for (deadlock) kill here. This helps prevent a lingering deadlock kill that occurred during normal DML processing to propagate past the mark_start_commit(). If we detect a deadlock only after mark_start_commit(), we have to unmark, which has at least a theoretical possibility of leaving a window where it looks like all transactions in a GCO have started committing, while in fact one will need to rollback and retry. This is not supposed to be possible (since there is a deadlock, at least one transaction should be blocked from reaching commit), but this seems a fragile ensurance, and there were historically a number of subtle bugs in this area. */ if (!thd->killed) { DEBUG_SYNC(thd, "rpl_parallel_before_mark_start_commit"); rgi->mark_start_commit(); DEBUG_SYNC(thd, "rpl_parallel_after_mark_start_commit"); } } /* If the SQL thread is stopping, we just skip execution of all the following event groups. We still do all the normal waiting and wakeup processing between the event groups as a simple way to ensure that everything is stopped and cleaned up correctly. */ if (likely(!rgi->worker_error) && !skip_event_group) { ++rgi->retry_event_count; #ifndef DBUG_OFF err= 0; DBUG_EXECUTE_IF("rpl_parallel_simulate_temp_err_xid", if (event_type == XID_EVENT) { thd->clear_error(); thd->get_stmt_da()->reset_diagnostics_area(); my_error(ER_LOCK_DEADLOCK, MYF(0)); err= 1; DEBUG_SYNC(thd, "rpl_parallel_simulate_temp_err_xid"); }); if (!err) #endif { if (unlikely(thd->check_killed())) { thd->clear_error(); thd->get_stmt_da()->reset_diagnostics_area(); thd->send_kill_message(); err= 1; } else err= rpt_handle_event(qev, rpt); } delete_or_keep_event_post_apply(rgi, event_type, qev->ev); DBUG_EXECUTE_IF("rpl_parallel_simulate_temp_err_gtid_0_x_100", err= dbug_simulate_tmp_error(rgi, thd);); if (unlikely(err)) { convert_kill_to_deadlock_error(rgi); if (has_temporary_error(thd) && slave_trans_retries > 0) err= retry_event_group(rgi, rpt, qev); } } else { delete qev->ev; thd->get_stmt_da()->set_overwrite_status(true); err= thd->wait_for_prior_commit(); thd->get_stmt_da()->set_overwrite_status(false); } end_of_group= in_event_group && ((group_standalone && !Log_event::is_part_of_group(event_type)) || group_ending); rpt->loc_free_qev(qev); if (unlikely(err)) { if (!rgi->worker_error) { slave_output_error_info(rgi, thd); signal_error_to_sql_driver_thread(thd, rgi, err); } thd->reset_killed(); } if (end_of_group) { in_event_group= false; finish_event_group(rpt, event_gtid_sub_id, entry, rgi); rpt->loc_free_rgi(rgi); thd->rgi_slave= group_rgi= rgi= NULL; skip_event_group= false; DEBUG_SYNC(thd, "rpl_parallel_end_of_group"); } } mysql_mutex_lock(&rpt->LOCK_rpl_thread); /* Now that we have the lock, we can move everything from our local free lists to the real free lists that are also accessible from the SQL driver thread. */ rpt->batch_free(); if ((events= rpt->event_queue) != NULL) { /* Take next group of events from the replication pool. This is faster than having to wakeup the pool manager thread to give us a new event. */ rpt->dequeue1(events); mysql_mutex_unlock(&rpt->LOCK_rpl_thread); goto more_events; } rpt->inuse_relaylog_refcount_update(); if (in_event_group && group_rgi->parallel_entry->force_abort) { /* We are asked to abort, without getting the remaining events in the current event group. We have to rollback the current transaction and update the last sub_id value so that SQL thread will know we are done with the half-processed event group. */ mysql_mutex_unlock(&rpt->LOCK_rpl_thread); signal_error_to_sql_driver_thread(thd, group_rgi, 1); finish_event_group(rpt, group_rgi->gtid_sub_id, group_rgi->parallel_entry, group_rgi); in_event_group= false; mysql_mutex_lock(&rpt->LOCK_rpl_thread); rpt->free_rgi(group_rgi); thd->rgi_slave= group_rgi= NULL; skip_event_group= false; } if (!in_event_group) { /* If we are in a FLUSH TABLES FOR READ LOCK, wait for it */ while (rpt->current_entry && rpt->pause_for_ftwrl) { /* We are currently in the delicate process of pausing parallel replication while FLUSH TABLES WITH READ LOCK is starting. We must not de-allocate the thread (setting rpt->current_owner= NULL) until rpl_unpause_after_ftwrl() has woken us up. */ rpl_parallel_entry *e= rpt->current_entry; /* Wait for rpl_unpause_after_ftwrl() to wake us up. Note that rpl_pause_for_ftwrl() may wait for 'e->pause_sub_id' to change. This should happen eventually in finish_event_group() */ mysql_mutex_lock(&e->LOCK_parallel_entry); mysql_mutex_unlock(&rpt->LOCK_rpl_thread); if (rpt->pause_for_ftwrl) mysql_cond_wait(&e->COND_parallel_entry, &e->LOCK_parallel_entry); mysql_mutex_unlock(&e->LOCK_parallel_entry); mysql_mutex_lock(&rpt->LOCK_rpl_thread); } rpt->current_owner= NULL; /* Tell wait_for_done() that we are done, if it is waiting. */ if (likely(rpt->current_entry) && unlikely(rpt->current_entry->force_abort)) mysql_cond_broadcast(&rpt->COND_rpl_thread_stop); rpt->current_entry= NULL; if (!rpt->stop) rpt->pool->release_thread(rpt); } } #ifdef WITH_WSREP wsrep_after_command_before_result(thd); wsrep_after_command_after_result(thd); wsrep_close(thd); #endif /* WITH_WSREP */ rpt->thd= NULL; mysql_mutex_unlock(&rpt->LOCK_rpl_thread); thd->clear_error(); thd->catalog= 0; thd->reset_query(); thd->reset_db(&null_clex_str); thd_proc_info(thd, "Slave worker thread exiting"); thd->temporary_tables= 0; THD_CHECK_SENTRY(thd); server_threads.erase(thd); delete thd; mysql_mutex_lock(&rpt->LOCK_rpl_thread); rpt->running= false; mysql_cond_signal(&rpt->COND_rpl_thread); mysql_mutex_unlock(&rpt->LOCK_rpl_thread); my_thread_end(); return NULL; } static void dealloc_gco(group_commit_orderer *gco) { mysql_cond_destroy(&gco->COND_group_commit_orderer); my_free(gco); } /** Change thread count for global parallel worker threads @param pool parallel thread pool @param new_count Number of threads to be in pool. 0 in shutdown @param force Force thread count to new_count even if slave threads are running By default we don't resize pool of there are running threads. However during shutdown we will always do it. This is needed as any_slave_sql_running() returns 1 during shutdown as we don't want to access master_info while Master_info_index::free_connections are running. */ static int rpl_parallel_change_thread_count(rpl_parallel_thread_pool *pool, uint32 new_count, bool force) { uint32 i; rpl_parallel_thread **old_list= NULL; rpl_parallel_thread **new_list= NULL; rpl_parallel_thread *new_free_list= NULL; rpl_parallel_thread *rpt_array= NULL; int res; if ((res= pool_mark_busy(pool, current_thd))) return res; /* Protect against parallel pool resizes */ if (pool->count == new_count) { pool_mark_not_busy(pool); return 0; } /* If we are about to delete pool, do an extra check that there are no new slave threads running since we marked pool busy */ if (!new_count && !force) { if (any_slave_sql_running(false)) { DBUG_PRINT("warning", ("SQL threads running while trying to reset parallel pool")); pool_mark_not_busy(pool); return 0; // Ok to not resize pool } } /* Allocate the new list of threads up-front. That way, if we fail half-way, we only need to free whatever we managed to allocate, and will not be left with a half-functional thread pool. */ if (new_count && !my_multi_malloc(PSI_INSTRUMENT_ME, MYF(MY_WME|MY_ZEROFILL), &new_list, new_count*sizeof(*new_list), &rpt_array, new_count*sizeof(*rpt_array), NULL)) { my_error(ER_OUTOFMEMORY, MYF(0), (int(new_count*sizeof(*new_list) + new_count*sizeof(*rpt_array)))); goto err; } for (i= 0; i < new_count; ++i) { pthread_t th; new_list[i]= &rpt_array[i]; new_list[i]->delay_start= true; mysql_mutex_init(key_LOCK_rpl_thread, &new_list[i]->LOCK_rpl_thread, MY_MUTEX_INIT_SLOW); mysql_cond_init(key_COND_rpl_thread, &new_list[i]->COND_rpl_thread, NULL); mysql_cond_init(key_COND_rpl_thread_queue, &new_list[i]->COND_rpl_thread_queue, NULL); mysql_cond_init(key_COND_rpl_thread_stop, &new_list[i]->COND_rpl_thread_stop, NULL); new_list[i]->pool= pool; if (mysql_thread_create(key_rpl_parallel_thread, &th, &connection_attrib, handle_rpl_parallel_thread, new_list[i])) { my_error(ER_OUT_OF_RESOURCES, MYF(0)); goto err; } new_list[i]->next= new_free_list; new_free_list= new_list[i]; } /* Grab each old thread in turn, and signal it to stop. Note that since we require all replication threads to be stopped before changing the parallel replication worker thread pool, all the threads will be already idle and will terminate immediately. */ for (i= 0; i < pool->count; ++i) { rpl_parallel_thread *rpt; mysql_mutex_lock(&pool->LOCK_rpl_thread_pool); while ((rpt= pool->free_list) == NULL) mysql_cond_wait(&pool->COND_rpl_thread_pool, &pool->LOCK_rpl_thread_pool); pool->free_list= rpt->next; mysql_mutex_unlock(&pool->LOCK_rpl_thread_pool); mysql_mutex_lock(&rpt->LOCK_rpl_thread); rpt->stop= true; mysql_cond_signal(&rpt->COND_rpl_thread); mysql_mutex_unlock(&rpt->LOCK_rpl_thread); } for (i= 0; i < pool->count; ++i) { rpl_parallel_thread *rpt= pool->threads[i]; mysql_mutex_lock(&rpt->LOCK_rpl_thread); while (rpt->running) mysql_cond_wait(&rpt->COND_rpl_thread, &rpt->LOCK_rpl_thread); mysql_mutex_unlock(&rpt->LOCK_rpl_thread); mysql_mutex_destroy(&rpt->LOCK_rpl_thread); mysql_cond_destroy(&rpt->COND_rpl_thread); while (rpt->qev_free_list) { rpl_parallel_thread::queued_event *next= rpt->qev_free_list->next; my_free(rpt->qev_free_list); rpt->qev_free_list= next; } while (rpt->rgi_free_list) { rpl_group_info *next= rpt->rgi_free_list->next; delete rpt->rgi_free_list; rpt->rgi_free_list= next; } while (rpt->gco_free_list) { group_commit_orderer *next= rpt->gco_free_list->next_gco; dealloc_gco(rpt->gco_free_list); rpt->gco_free_list= next; } } old_list= pool->threads; if (new_count < pool->count) pool->count= new_count; pool->threads= new_list; if (new_count > pool->count) pool->count= new_count; my_free(old_list); pool->free_list= new_free_list; for (i= 0; i < pool->count; ++i) { mysql_mutex_lock(&pool->threads[i]->LOCK_rpl_thread); pool->threads[i]->delay_start= false; mysql_cond_signal(&pool->threads[i]->COND_rpl_thread); while (!pool->threads[i]->running) mysql_cond_wait(&pool->threads[i]->COND_rpl_thread, &pool->threads[i]->LOCK_rpl_thread); mysql_mutex_unlock(&pool->threads[i]->LOCK_rpl_thread); } pool_mark_not_busy(pool); return 0; err: if (new_list) { while (new_free_list) { mysql_mutex_lock(&new_free_list->LOCK_rpl_thread); new_free_list->delay_start= false; new_free_list->stop= true; mysql_cond_signal(&new_free_list->COND_rpl_thread); while (!new_free_list->running) mysql_cond_wait(&new_free_list->COND_rpl_thread, &new_free_list->LOCK_rpl_thread); while (new_free_list->running) mysql_cond_wait(&new_free_list->COND_rpl_thread, &new_free_list->LOCK_rpl_thread); mysql_mutex_unlock(&new_free_list->LOCK_rpl_thread); new_free_list= new_free_list->next; } my_free(new_list); } pool_mark_not_busy(pool); return 1; } /* Deactivate the parallel replication thread pool, if there are now no more SQL threads running. */ int rpl_parallel_resize_pool_if_no_slaves(void) { /* master_info_index is set to NULL on shutdown */ if (opt_slave_parallel_threads > 0 && !any_slave_sql_running(false)) return rpl_parallel_inactivate_pool(&global_rpl_thread_pool); return 0; } /** Pool activation is preceeded by taking a "lock" of pool_mark_busy which guarantees the number of running slaves drops to zero atomicly with the number of pool workers. This resolves race between the function caller thread and one that may be attempting to deactivate the pool. */ int rpl_parallel_activate_pool(rpl_parallel_thread_pool *pool) { int rc= 0; if ((rc= pool_mark_busy(pool, current_thd))) return rc; // killed if (!pool->count) { pool_mark_not_busy(pool); rc= rpl_parallel_change_thread_count(pool, opt_slave_parallel_threads, 0); } else { pool_mark_not_busy(pool); } return rc; } int rpl_parallel_inactivate_pool(rpl_parallel_thread_pool *pool) { return rpl_parallel_change_thread_count(pool, 0, 0); } void rpl_parallel_thread::batch_free() { mysql_mutex_assert_owner(&LOCK_rpl_thread); if (loc_qev_list) { *loc_qev_last_ptr_ptr= qev_free_list; qev_free_list= loc_qev_list; loc_qev_list= NULL; dequeue2(loc_qev_size); /* Signal that our queue can now accept more events. */ mysql_cond_signal(&COND_rpl_thread_queue); loc_qev_size= 0; qev_free_pending= 0; } if (loc_rgi_list) { *loc_rgi_last_ptr_ptr= rgi_free_list; rgi_free_list= loc_rgi_list; loc_rgi_list= NULL; } if (loc_gco_list) { *loc_gco_last_ptr_ptr= gco_free_list; gco_free_list= loc_gco_list; loc_gco_list= NULL; } } void rpl_parallel_thread::inuse_relaylog_refcount_update() { inuse_relaylog *ir= accumulated_ir_last; if (ir) { ir->dequeued_count+= accumulated_ir_count; accumulated_ir_count= 0; accumulated_ir_last= NULL; } } rpl_parallel_thread::queued_event * rpl_parallel_thread::get_qev_common(Log_event *ev, ulonglong event_size) { queued_event *qev; mysql_mutex_assert_owner(&LOCK_rpl_thread); if ((qev= qev_free_list)) qev_free_list= qev->next; else if(!(qev= (queued_event *)my_malloc(PSI_INSTRUMENT_ME, sizeof(*qev), MYF(0)))) { my_error(ER_OUTOFMEMORY, MYF(0), (int)sizeof(*qev)); return NULL; } qev->typ= rpl_parallel_thread::queued_event::QUEUED_EVENT; qev->ev= ev; qev->event_size= (size_t)event_size; qev->next= NULL; return qev; } rpl_parallel_thread::queued_event * rpl_parallel_thread::get_qev(Log_event *ev, ulonglong event_size, Relay_log_info *rli) { queued_event *qev= get_qev_common(ev, event_size); if (!qev) return NULL; strcpy(qev->event_relay_log_name, rli->event_relay_log_name); qev->event_relay_log_pos= rli->event_relay_log_pos; qev->future_event_relay_log_pos= rli->future_event_relay_log_pos; strcpy(qev->future_event_master_log_name, rli->future_event_master_log_name); return qev; } rpl_parallel_thread::queued_event * rpl_parallel_thread::retry_get_qev(Log_event *ev, queued_event *orig_qev, const char *relay_log_name, ulonglong event_pos, ulonglong event_size) { queued_event *qev= get_qev_common(ev, event_size); if (!qev) return NULL; qev->rgi= orig_qev->rgi; strcpy(qev->event_relay_log_name, relay_log_name); qev->event_relay_log_pos= event_pos; qev->future_event_relay_log_pos= event_pos+event_size; strcpy(qev->future_event_master_log_name, orig_qev->future_event_master_log_name); return qev; } void rpl_parallel_thread::loc_free_qev(rpl_parallel_thread::queued_event *qev) { inuse_relaylog *ir= qev->ir; inuse_relaylog *last_ir= accumulated_ir_last; if (ir != last_ir) { if (last_ir) inuse_relaylog_refcount_update(); accumulated_ir_last= ir; } ++accumulated_ir_count; if (!loc_qev_list) loc_qev_last_ptr_ptr= &qev->next; else qev->next= loc_qev_list; loc_qev_list= qev; loc_qev_size+= qev->event_size; /* We want to release to the global free list only occasionally, to avoid having to take the LOCK_rpl_thread muted too many times. However, we do need to release regularly. If we let the unreleased part grow too large, then the SQL driver thread may go to sleep waiting for the queue to drop below opt_slave_parallel_max_queued, and this in turn can stall all other worker threads for more stuff to do. */ if (++qev_free_pending >= QEV_BATCH_FREE || loc_qev_size >= opt_slave_parallel_max_queued/3) { mysql_mutex_lock(&LOCK_rpl_thread); batch_free(); mysql_mutex_unlock(&LOCK_rpl_thread); } } void rpl_parallel_thread::free_qev(rpl_parallel_thread::queued_event *qev) { mysql_mutex_assert_owner(&LOCK_rpl_thread); qev->next= qev_free_list; qev_free_list= qev; } rpl_group_info* rpl_parallel_thread::get_rgi(Relay_log_info *rli, Gtid_log_event *gtid_ev, rpl_parallel_entry *e, ulonglong event_size) { rpl_group_info *rgi; mysql_mutex_assert_owner(&LOCK_rpl_thread); if ((rgi= rgi_free_list)) { rgi_free_list= rgi->next; rgi->reinit(rli); } else { if(!(rgi= new rpl_group_info(rli))) { my_error(ER_OUTOFMEMORY, MYF(0), (int)sizeof(*rgi)); return NULL; } rgi->is_parallel_exec = true; } if ((rgi->deferred_events_collecting= rli->mi->rpl_filter->is_on()) && !rgi->deferred_events) rgi->deferred_events= new Deferred_log_events(rli); if (event_group_new_gtid(rgi, gtid_ev)) { free_rgi(rgi); my_error(ER_OUT_OF_RESOURCES, MYF(MY_WME)); return NULL; } rgi->parallel_entry= e; rgi->relay_log= rli->last_inuse_relaylog; rgi->retry_start_offset= rli->future_event_relay_log_pos-event_size; rgi->retry_event_count= 0; rgi->killed_for_retry= rpl_group_info::RETRY_KILL_NONE; return rgi; } void rpl_parallel_thread::loc_free_rgi(rpl_group_info *rgi) { DBUG_ASSERT(rgi->commit_orderer.waitee == NULL); rgi->free_annotate_event(); if (!loc_rgi_list) loc_rgi_last_ptr_ptr= &rgi->next; else rgi->next= loc_rgi_list; loc_rgi_list= rgi; } void rpl_parallel_thread::free_rgi(rpl_group_info *rgi) { mysql_mutex_assert_owner(&LOCK_rpl_thread); DBUG_ASSERT(rgi->commit_orderer.waitee == NULL); rgi->free_annotate_event(); rgi->next= rgi_free_list; rgi_free_list= rgi; } group_commit_orderer * rpl_parallel_thread::get_gco(uint64 wait_count, group_commit_orderer *prev, uint64 prior_sub_id) { group_commit_orderer *gco; mysql_mutex_assert_owner(&LOCK_rpl_thread); if ((gco= gco_free_list)) gco_free_list= gco->next_gco; else if(!(gco= (group_commit_orderer *)my_malloc(PSI_INSTRUMENT_ME, sizeof(*gco), MYF(0)))) { my_error(ER_OUTOFMEMORY, MYF(0), (int)sizeof(*gco)); return NULL; } mysql_cond_init(key_COND_group_commit_orderer, &gco->COND_group_commit_orderer, NULL); gco->wait_count= wait_count; gco->prev_gco= prev; gco->next_gco= NULL; gco->prior_sub_id= prior_sub_id; gco->installed= false; gco->flags= 0; return gco; } void rpl_parallel_thread::loc_free_gco(group_commit_orderer *gco) { if (!loc_gco_list) loc_gco_last_ptr_ptr= &gco->next_gco; else gco->next_gco= loc_gco_list; loc_gco_list= gco; } rpl_parallel_thread_pool::rpl_parallel_thread_pool() : threads(0), free_list(0), count(0), inited(false), busy(false) { } int rpl_parallel_thread_pool::init(uint32 size) { threads= NULL; free_list= NULL; count= 0; busy= false; mysql_mutex_init(key_LOCK_rpl_thread_pool, &LOCK_rpl_thread_pool, MY_MUTEX_INIT_SLOW); mysql_cond_init(key_COND_rpl_thread_pool, &COND_rpl_thread_pool, NULL); inited= true; /* The pool is initially empty. Threads will be spawned when a slave SQL thread is started. */ return 0; } void rpl_parallel_thread_pool::destroy() { deactivate(); destroy_cond_mutex(); } void rpl_parallel_thread_pool::deactivate() { if (!inited) return; rpl_parallel_change_thread_count(this, 0, 1); } void rpl_parallel_thread_pool::destroy_cond_mutex() { if (!inited) return; mysql_mutex_destroy(&LOCK_rpl_thread_pool); mysql_cond_destroy(&COND_rpl_thread_pool); inited= false; } /* Wait for a worker thread to become idle. When one does, grab the thread for our use and return it. Note that we return with the worker threads's LOCK_rpl_thread mutex locked. */ struct rpl_parallel_thread * rpl_parallel_thread_pool::get_thread(rpl_parallel_thread **owner, rpl_parallel_entry *entry) { rpl_parallel_thread *rpt; DBUG_ASSERT(count > 0); mysql_mutex_lock(&LOCK_rpl_thread_pool); while (unlikely(busy) || !(rpt= free_list)) mysql_cond_wait(&COND_rpl_thread_pool, &LOCK_rpl_thread_pool); free_list= rpt->next; mysql_mutex_unlock(&LOCK_rpl_thread_pool); mysql_mutex_lock(&rpt->LOCK_rpl_thread); rpt->current_owner= owner; rpt->current_entry= entry; return rpt; } /* Release a thread to the thread pool. The thread should be locked, and should not have any work queued for it. */ void rpl_parallel_thread_pool::release_thread(rpl_parallel_thread *rpt) { rpl_parallel_thread *list; mysql_mutex_assert_owner(&rpt->LOCK_rpl_thread); DBUG_ASSERT(rpt->current_owner == NULL); mysql_mutex_lock(&LOCK_rpl_thread_pool); list= free_list; rpt->next= list; free_list= rpt; if (!list) mysql_cond_broadcast(&COND_rpl_thread_pool); mysql_mutex_unlock(&LOCK_rpl_thread_pool); } /* Obtain a worker thread that we can queue an event to. Each invocation allocates a new worker thread, to maximise parallelism. However, only up to a maximum of --slave-domain-parallel-threads workers can be occupied by a single replication domain; after that point, we start re-using worker threads that are still executing events that were queued earlier for this thread. We never queue more than --rpl-parallel-wait-queue_max amount of events for one worker, to avoid the SQL driver thread using up all memory with queued events while worker threads are stalling. Note that this function returns with rpl_parallel_thread::LOCK_rpl_thread locked. Exception is if we were killed, in which case NULL is returned. The *did_enter_cond flag is set true if we had to wait for a worker thread to become free (with mysql_cond_wait()). If so, old_stage will also be set, and the LOCK_rpl_thread must be released with THD::EXIT_COND() instead of mysql_mutex_unlock. When `gtid_ev' is not NULL the last worker thread will be returned again, if it is still available. Otherwise a new worker thread is allocated. A worker for XA transaction is determined through xid hashing which ensure for a XA-complete to be scheduled to the same-xid XA-prepare worker. */ rpl_parallel_thread * rpl_parallel_entry::choose_thread(rpl_group_info *rgi, bool *did_enter_cond, PSI_stage_info *old_stage, Gtid_log_event *gtid_ev) { uint32 idx; Relay_log_info *rli= rgi->rli; rpl_parallel_thread *thr; idx= rpl_thread_idx; if (gtid_ev) { if (gtid_ev->flags2 & (Gtid_log_event::FL_COMPLETED_XA | Gtid_log_event::FL_PREPARED_XA)) idx= my_hash_sort(&my_charset_bin, gtid_ev->xid.key(), gtid_ev->xid.key_length()) % rpl_thread_max; else { ++idx; if (idx >= rpl_thread_max) idx= 0; } rpl_thread_idx= idx; } thr= rpl_threads[idx]; if (thr) { *did_enter_cond= false; mysql_mutex_lock(&thr->LOCK_rpl_thread); for (;;) { if (thr->current_owner != &rpl_threads[idx]) { /* The worker thread became idle, and returned to the free list and possibly was allocated to a different request. So we should allocate a new worker thread. */ unlock_or_exit_cond(rli->sql_driver_thd, &thr->LOCK_rpl_thread, did_enter_cond, old_stage); thr= NULL; break; } else if (thr->queued_size <= opt_slave_parallel_max_queued) { /* The thread is ready to queue into. */ break; } else if (unlikely(rli->sql_driver_thd->check_killed(1))) { unlock_or_exit_cond(rli->sql_driver_thd, &thr->LOCK_rpl_thread, did_enter_cond, old_stage); my_error(ER_CONNECTION_KILLED, MYF(0)); #ifdef ENABLED_DEBUG_SYNC DBUG_EXECUTE_IF("rpl_parallel_wait_queue_max", { debug_sync_set_action(rli->sql_driver_thd, STRING_WITH_LEN("now SIGNAL wait_queue_killed")); };); #endif slave_output_error_info(rgi, rli->sql_driver_thd); return NULL; } else { /* We have reached the limit of how much memory we are allowed to use for queuing events, so wait for the thread to consume some of its queue. */ if (!*did_enter_cond) { /* We need to do the debug_sync before ENTER_COND(). Because debug_sync changes the thd->mysys_var->current_mutex, and this can cause THD::awake to use the wrong mutex. */ #ifdef ENABLED_DEBUG_SYNC DBUG_EXECUTE_IF("rpl_parallel_wait_queue_max", { debug_sync_set_action(rli->sql_driver_thd, STRING_WITH_LEN("now SIGNAL wait_queue_ready")); };); #endif rli->sql_driver_thd->ENTER_COND(&thr->COND_rpl_thread_queue, &thr->LOCK_rpl_thread, &stage_waiting_for_room_in_worker_thread, old_stage); *did_enter_cond= true; } mysql_cond_wait(&thr->COND_rpl_thread_queue, &thr->LOCK_rpl_thread); } } } if (!thr) rpl_threads[idx]= thr= global_rpl_thread_pool.get_thread(&rpl_threads[idx], this); return thr; } static void free_rpl_parallel_entry(void *element) { rpl_parallel_entry *e= (rpl_parallel_entry *)element; while (e->current_gco) { group_commit_orderer *prev_gco= e->current_gco->prev_gco; dealloc_gco(e->current_gco); e->current_gco= prev_gco; } mysql_cond_destroy(&e->COND_parallel_entry); mysql_mutex_destroy(&e->LOCK_parallel_entry); my_free(e); } rpl_parallel::rpl_parallel() : current(NULL), sql_thread_stopping(false) { my_hash_init(PSI_INSTRUMENT_ME, &domain_hash, &my_charset_bin, 32, offsetof(rpl_parallel_entry, domain_id), sizeof(uint32), NULL, free_rpl_parallel_entry, HASH_UNIQUE); } void rpl_parallel::reset() { my_hash_reset(&domain_hash); current= NULL; sql_thread_stopping= false; } rpl_parallel::~rpl_parallel() { my_hash_free(&domain_hash); } rpl_parallel_entry * rpl_parallel::find(uint32 domain_id) { struct rpl_parallel_entry *e; if (!(e= (rpl_parallel_entry *)my_hash_search(&domain_hash, (const uchar *)&domain_id, 0))) { /* Allocate a new, empty one. */ ulong count= opt_slave_domain_parallel_threads; if (count == 0 || count > opt_slave_parallel_threads) count= opt_slave_parallel_threads; rpl_parallel_thread **p; if (!my_multi_malloc(PSI_INSTRUMENT_ME, MYF(MY_WME|MY_ZEROFILL), &e, sizeof(*e), &p, count*sizeof(*p), NULL)) { my_error(ER_OUTOFMEMORY, MYF(0), (int)(sizeof(*e)+count*sizeof(*p))); return NULL; } e->rpl_threads= p; e->rpl_thread_max= count; e->domain_id= domain_id; e->stop_on_error_sub_id= (uint64)ULONGLONG_MAX; e->pause_sub_id= (uint64)ULONGLONG_MAX; if (my_hash_insert(&domain_hash, (uchar *)e)) { my_free(e); return NULL; } mysql_mutex_init(key_LOCK_parallel_entry, &e->LOCK_parallel_entry, MY_MUTEX_INIT_FAST); mysql_cond_init(key_COND_parallel_entry, &e->COND_parallel_entry, NULL); } else e->force_abort= false; return e; } /** Wait until all sql worker threads has stopped processing This is called when sql thread has been killed/stopped */ void rpl_parallel::wait_for_done(THD *thd, Relay_log_info *rli) { struct rpl_parallel_entry *e; rpl_parallel_thread *rpt; uint32 i, j; /* First signal all workers that they must force quit; no more events will be queued to complete any partial event groups executed. */ for (i= 0; i < domain_hash.records; ++i) { e= (struct rpl_parallel_entry *)my_hash_element(&domain_hash, i); mysql_mutex_lock(&e->LOCK_parallel_entry); /* We want the worker threads to stop as quickly as is safe. If the slave SQL threads are behind, we could have significant amount of events queued for the workers, and we want to stop without waiting for them all to be applied first. But if any event group has already started executing in a worker, we want to be sure that all prior event groups are also executed, so that we stop at a consistent point in the binlog stream (per replication domain). All event groups wait for e->count_committing_event_groups to reach the value of group_commit_orderer::wait_count before starting to execute. Thus, at this point we know that any event group with a strictly larger wait_count are safe to skip, none of them can have started executing yet. So we set e->stop_count here and use it to decide in the worker threads whether to continue executing an event group or whether to skip it, when force_abort is set. If we stop due to reaching the START SLAVE UNTIL condition, then we need to continue executing any queued events up to that point. */ e->force_abort= true; e->stop_count= rli->stop_for_until ? e->count_queued_event_groups : e->count_committing_event_groups; mysql_mutex_unlock(&e->LOCK_parallel_entry); for (j= 0; j < e->rpl_thread_max; ++j) { if ((rpt= e->rpl_threads[j])) { mysql_mutex_lock(&rpt->LOCK_rpl_thread); if (rpt->current_owner == &e->rpl_threads[j]) mysql_cond_signal(&rpt->COND_rpl_thread); mysql_mutex_unlock(&rpt->LOCK_rpl_thread); } } } #ifdef ENABLED_DEBUG_SYNC DBUG_EXECUTE_IF("rpl_parallel_wait_for_done_trigger", { debug_sync_set_action(thd, STRING_WITH_LEN("now SIGNAL wait_for_done_waiting")); };); #endif for (i= 0; i < domain_hash.records; ++i) { e= (struct rpl_parallel_entry *)my_hash_element(&domain_hash, i); for (j= 0; j < e->rpl_thread_max; ++j) { if ((rpt= e->rpl_threads[j])) { mysql_mutex_lock(&rpt->LOCK_rpl_thread); while (rpt->current_owner == &e->rpl_threads[j]) mysql_cond_wait(&rpt->COND_rpl_thread_stop, &rpt->LOCK_rpl_thread); mysql_mutex_unlock(&rpt->LOCK_rpl_thread); } } } } /* This function handles the case where the SQL driver thread reached the START SLAVE UNTIL position; we stop queueing more events but continue processing remaining, already queued events; then use executes manual STOP SLAVE; then this function signals to worker threads that they should stop the processing of any remaining queued events. */ void rpl_parallel::stop_during_until() { struct rpl_parallel_entry *e; uint32 i; for (i= 0; i < domain_hash.records; ++i) { e= (struct rpl_parallel_entry *)my_hash_element(&domain_hash, i); mysql_mutex_lock(&e->LOCK_parallel_entry); if (e->force_abort) e->stop_count= e->count_committing_event_groups; mysql_mutex_unlock(&e->LOCK_parallel_entry); } } bool rpl_parallel::workers_idle() { struct rpl_parallel_entry *e; uint32 i, max_i; max_i= domain_hash.records; for (i= 0; i < max_i; ++i) { bool active; e= (struct rpl_parallel_entry *)my_hash_element(&domain_hash, i); mysql_mutex_lock(&e->LOCK_parallel_entry); active= e->current_sub_id > e->last_committed_sub_id; mysql_mutex_unlock(&e->LOCK_parallel_entry); if (active) break; } return (i == max_i); } int rpl_parallel_entry::queue_master_restart(rpl_group_info *rgi, Format_description_log_event *fdev) { uint32 idx; rpl_parallel_thread *thr; rpl_parallel_thread::queued_event *qev; Relay_log_info *rli= rgi->rli; /* We only need to queue the server restart if we still have a thread working on a (potentially partial) event group. If the last thread we queued for has finished, then it cannot have any partial event group that needs aborting. Thus there is no need for the full complexity of choose_thread(). We only need to check if we have a current worker thread, and queue for it if so. */ idx= rpl_thread_idx; thr= rpl_threads[idx]; if (!thr) return 0; mysql_mutex_lock(&thr->LOCK_rpl_thread); if (thr->current_owner != &rpl_threads[idx]) { /* No active worker thread, so no need to queue the master restart. */ mysql_mutex_unlock(&thr->LOCK_rpl_thread); return 0; } if (!(qev= thr->get_qev(fdev, 0, rli))) { mysql_mutex_unlock(&thr->LOCK_rpl_thread); return 1; } qev->rgi= rgi; qev->typ= rpl_parallel_thread::queued_event::QUEUED_MASTER_RESTART; qev->entry_for_queued= this; qev->ir= rli->last_inuse_relaylog; ++qev->ir->queued_count; thr->enqueue(qev); mysql_cond_signal(&thr->COND_rpl_thread); mysql_mutex_unlock(&thr->LOCK_rpl_thread); return 0; } int rpl_parallel::wait_for_workers_idle(THD *thd) { uint32 i, max_i; /* The domain_hash is only accessed by the SQL driver thread, so it is safe to iterate over without a lock. */ max_i= domain_hash.records; for (i= 0; i < max_i; ++i) { PSI_stage_info old_stage; struct rpl_parallel_entry *e; int err= 0; e= (struct rpl_parallel_entry *)my_hash_element(&domain_hash, i); mysql_mutex_lock(&e->LOCK_parallel_entry); ++e->need_sub_id_signal; thd->ENTER_COND(&e->COND_parallel_entry, &e->LOCK_parallel_entry, &stage_waiting_for_workers_idle, &old_stage); while (e->current_sub_id > e->last_committed_sub_id) { if (unlikely(thd->check_killed())) { err= 1; break; } mysql_cond_wait(&e->COND_parallel_entry, &e->LOCK_parallel_entry); } --e->need_sub_id_signal; thd->EXIT_COND(&old_stage); if (err) return err; } return 0; } /* Handle seeing a GTID during slave restart in GTID mode. If we stopped with different replication domains having reached different positions in the relay log, we need to skip event groups in domains that are further progressed. Updates the state with the seen GTID, and returns true if this GTID should be skipped, false otherwise. */ bool process_gtid_for_restart_pos(Relay_log_info *rli, rpl_gtid *gtid) { slave_connection_state::entry *gtid_entry; slave_connection_state *state= &rli->restart_gtid_pos; if (likely(state->count() == 0) || !(gtid_entry= state->find_entry(gtid->domain_id))) return false; if (gtid->server_id == gtid_entry->gtid.server_id) { uint64 seq_no= gtid_entry->gtid.seq_no; if (gtid->seq_no >= seq_no) { /* This domain has reached its start position. So remove it, so that further events will be processed normally. */ state->remove(>id_entry->gtid); } return gtid->seq_no <= seq_no; } else return true; } /* This is used when we get an error during processing in do_event(); We will not queue any event to the thread, but we still need to wake it up to be sure that it will be returned to the pool. */ static void abandon_worker_thread(THD *thd, rpl_parallel_thread *cur_thread, bool *did_enter_cond, PSI_stage_info *old_stage) { unlock_or_exit_cond(thd, &cur_thread->LOCK_rpl_thread, did_enter_cond, old_stage); mysql_cond_signal(&cur_thread->COND_rpl_thread); } /* do_event() is executed by the sql_driver_thd thread. It's main purpose is to find a thread that can execute the query. @retval 0 ok, event was accepted @retval 1 error @retval -1 event should be executed serially, in the sql driver thread */ int rpl_parallel::do_event(rpl_group_info *serial_rgi, Log_event *ev, ulonglong event_size) { rpl_parallel_entry *e; rpl_parallel_thread *cur_thread; rpl_parallel_thread::queued_event *qev; rpl_group_info *rgi= NULL; Relay_log_info *rli= serial_rgi->rli; enum Log_event_type typ; bool is_group_event; bool did_enter_cond= false; PSI_stage_info old_stage; DBUG_EXECUTE_IF("slave_crash_if_parallel_apply", DBUG_SUICIDE();); /* Handle master log name change, seen in Rotate_log_event. */ typ= ev->get_type_code(); if (unlikely(typ == ROTATE_EVENT)) { Rotate_log_event *rev= static_cast(ev); if ((rev->server_id != global_system_variables.server_id || rli->replicate_same_server_id) && !rev->is_relay_log_event() && !rli->is_in_group()) { memcpy(rli->future_event_master_log_name, rev->new_log_ident, rev->ident_len+1); rli->notify_group_master_log_name_update(); } } /* Execute queries non-parallel if slave_skip_counter is set, as it's is easier to skip queries in single threaded mode. */ if (rli->slave_skip_counter) return -1; /* Execute pre-10.0 event, which have no GTID, in single-threaded mode. */ is_group_event= Log_event::is_group_event(typ); if (unlikely(!current) && typ != GTID_EVENT && !(unlikely(rli->gtid_skip_flag != GTID_SKIP_NOT) && is_group_event)) return -1; /* Note: rli->data_lock is released by sql_delay_event(). */ if (sql_delay_event(ev, rli->sql_driver_thd, serial_rgi)) { /* If sql_delay_event() returns non-zero, it means that the wait timed out due to slave stop. We should not queue the event in this case, it must not be applied yet. */ delete ev; return 1; } if (unlikely(typ == FORMAT_DESCRIPTION_EVENT)) { Format_description_log_event *fdev= static_cast(ev); if (fdev->created) { /* This format description event marks a new binlog after a master server restart. We are going to close all temporary tables to clean up any possible left-overs after a prior master crash. Thus we need to wait for all prior events to execute to completion, in case they need access to any of the temporary tables. We also need to notify the worker thread running the prior incomplete event group (if any), as such event group signifies an incompletely written group cut short by a master crash, and must be rolled back. */ if (current->queue_master_restart(serial_rgi, fdev) || wait_for_workers_idle(rli->sql_driver_thd)) { delete ev; return 1; } } } else if (unlikely(typ == GTID_LIST_EVENT)) { Gtid_list_log_event *glev= static_cast(ev); rpl_gtid *list= glev->list; uint32 count= glev->count; rli->update_relay_log_state(list, count); while (count) { process_gtid_for_restart_pos(rli, list); ++list; --count; } } /* Stop queueing additional event groups once the SQL thread is requested to stop. We have to queue any remaining events of any event group that has already been partially queued, but after that we will just ignore any further events the SQL driver thread may try to queue, and eventually it will stop. */ if ((typ == GTID_EVENT || !is_group_event) && rli->abort_slave) sql_thread_stopping= true; if (sql_thread_stopping) { delete ev; /* Return "no error"; normal stop is not an error, and otherwise the error has already been recorded. */ return 0; } if (unlikely(rli->gtid_skip_flag != GTID_SKIP_NOT) && is_group_event) { if (typ == GTID_EVENT) rli->gtid_skip_flag= GTID_SKIP_NOT; else { if (rli->gtid_skip_flag == GTID_SKIP_STANDALONE) { if (!Log_event::is_part_of_group(typ)) rli->gtid_skip_flag= GTID_SKIP_NOT; } else { DBUG_ASSERT(rli->gtid_skip_flag == GTID_SKIP_TRANSACTION); if (typ == XID_EVENT || typ == XA_PREPARE_LOG_EVENT || (typ == QUERY_EVENT && // COMMIT/ROLLBACK are never compressed (((Query_log_event *)ev)->is_commit() || ((Query_log_event *)ev)->is_rollback()))) rli->gtid_skip_flag= GTID_SKIP_NOT; } delete_or_keep_event_post_apply(serial_rgi, typ, ev); return 0; } } Gtid_log_event *gtid_ev= NULL; if (typ == GTID_EVENT) { rpl_gtid gtid; gtid_ev= static_cast(ev); uint32 domain_id= (rli->mi->using_gtid == Master_info::USE_GTID_NO || rli->mi->parallel_mode <= SLAVE_PARALLEL_MINIMAL ? 0 : gtid_ev->domain_id); if (!(e= find(domain_id))) { my_error(ER_OUT_OF_RESOURCES, MYF(MY_WME)); delete ev; return 1; } current= e; gtid.domain_id= gtid_ev->domain_id; gtid.server_id= gtid_ev->server_id; gtid.seq_no= gtid_ev->seq_no; rli->update_relay_log_state(>id, 1); if (process_gtid_for_restart_pos(rli, >id)) { /* This domain has progressed further into the relay log before the last SQL thread restart. So we need to skip this event group to not doubly apply it. */ rli->gtid_skip_flag= ((gtid_ev->flags2 & Gtid_log_event::FL_STANDALONE) ? GTID_SKIP_STANDALONE : GTID_SKIP_TRANSACTION); delete_or_keep_event_post_apply(serial_rgi, typ, ev); return 0; } } else e= current; /* Find a worker thread to queue the event for. Prefer a new thread, so we maximise parallelism (at least for the group commit). But do not exceed a limit of --slave-domain-parallel-threads; instead re-use a thread that we queued for previously. */ cur_thread= e->choose_thread(serial_rgi, &did_enter_cond, &old_stage, gtid_ev); if (!cur_thread) { /* This means we were killed. The error is already signalled. */ delete ev; return 1; } if (!(qev= cur_thread->get_qev(ev, event_size, rli))) { abandon_worker_thread(rli->sql_driver_thd, cur_thread, &did_enter_cond, &old_stage); delete ev; return 1; } if (typ == GTID_EVENT) { bool new_gco; enum_slave_parallel_mode mode= rli->mi->parallel_mode; uchar gtid_flags= gtid_ev->flags2; group_commit_orderer *gco; uint8 force_switch_flag; enum rpl_group_info::enum_speculation speculation; if (!(rgi= cur_thread->get_rgi(rli, gtid_ev, e, event_size))) { cur_thread->free_qev(qev); abandon_worker_thread(rli->sql_driver_thd, cur_thread, &did_enter_cond, &old_stage); delete ev; return 1; } /* We queue the event group in a new worker thread, to run in parallel with previous groups. To preserve commit order within the replication domain, we set up rgi->wait_commit_sub_id to make the new group commit only after the previous group has committed. Event groups that group-committed together on the master can be run in parallel with each other without restrictions. But one batch of group-commits may not start before all groups in the previous batch have initiated their commit phase; we set up rgi->gco to ensure that. */ rgi->wait_commit_sub_id= e->current_sub_id; rgi->wait_commit_group_info= e->current_group_info; speculation= rpl_group_info::SPECULATE_NO; new_gco= true; force_switch_flag= 0; gco= e->current_gco; if (likely(gco)) { uint8 flags= gco->flags; if (mode <= SLAVE_PARALLEL_MINIMAL || !(gtid_flags & Gtid_log_event::FL_GROUP_COMMIT_ID) || e->last_commit_id != gtid_ev->commit_id) flags|= group_commit_orderer::MULTI_BATCH; /* Make sure we do not attempt to run DDL in parallel speculatively. */ if (gtid_flags & Gtid_log_event::FL_DDL) flags|= (force_switch_flag= group_commit_orderer::FORCE_SWITCH); if (!(flags & group_commit_orderer::MULTI_BATCH)) { /* Still the same batch of event groups that group-committed together on the master, so we can run in parallel. */ new_gco= false; } else if ((mode >= SLAVE_PARALLEL_OPTIMISTIC) && !(flags & group_commit_orderer::FORCE_SWITCH)) { /* In transactional parallel mode, we optimistically attempt to run non-DDL in parallel. In case of conflicts, we catch the conflict as a deadlock or other error, roll back and retry serially. The assumption is that only a few event groups will be non-transactional or otherwise unsuitable for parallel apply. Those transactions are still scheduled in parallel, but we set a flag that will make the worker thread wait for everything before to complete before starting. */ new_gco= false; if (!(gtid_flags & Gtid_log_event::FL_TRANSACTIONAL) || ( (!(gtid_flags & Gtid_log_event::FL_ALLOW_PARALLEL) || (gtid_flags & Gtid_log_event::FL_WAITED)) && (mode < SLAVE_PARALLEL_AGGRESSIVE))) { /* This transaction should not be speculatively run in parallel with what came before, either because it cannot safely be rolled back in case of a conflict, or because it was marked as likely to conflict and require expensive rollback and retry. Here we mark it as such, and then the worker thread will do a wait_for_prior_commit() before starting it. We do not introduce a new group_commit_orderer, since we still want following transactions to run in parallel with transactions prior to this one. */ speculation= rpl_group_info::SPECULATE_WAIT; } else speculation= rpl_group_info::SPECULATE_OPTIMISTIC; } gco->flags= flags; } else { if (gtid_flags & Gtid_log_event::FL_DDL) force_switch_flag= group_commit_orderer::FORCE_SWITCH; } rgi->speculation= speculation; if (gtid_flags & Gtid_log_event::FL_GROUP_COMMIT_ID) e->last_commit_id= gtid_ev->commit_id; else e->last_commit_id= 0; if (new_gco) { /* Do not run this event group in parallel with what came before; instead wait for everything prior to at least have started its commit phase, to avoid any risk of performing any conflicting action too early. Remember the count that marks the end of the previous batch of event groups that run in parallel, and allocate a new gco. */ uint64 count= e->count_queued_event_groups; if (!(gco= cur_thread->get_gco(count, gco, e->current_sub_id))) { cur_thread->free_rgi(rgi); cur_thread->free_qev(qev); abandon_worker_thread(rli->sql_driver_thd, cur_thread, &did_enter_cond, &old_stage); delete ev; return 1; } gco->flags|= force_switch_flag; e->current_gco= gco; } rgi->gco= gco; qev->rgi= e->current_group_info= rgi; e->current_sub_id= rgi->gtid_sub_id; ++e->count_queued_event_groups; } else if (!is_group_event) { int err; bool tmp; /* Events like ROTATE and FORMAT_DESCRIPTION. Do not run in worker thread. Same for events not preceeded by GTID (we should not see those normally, but they might be from an old master). */ qev->rgi= serial_rgi; tmp= serial_rgi->is_parallel_exec; serial_rgi->is_parallel_exec= true; err= rpt_handle_event(qev, NULL); serial_rgi->is_parallel_exec= tmp; if (ev->is_relay_log_event()) qev->future_event_master_log_pos= 0; else if (typ == ROTATE_EVENT) qev->future_event_master_log_pos= (static_cast(ev))->pos; else qev->future_event_master_log_pos= ev->log_pos; delete_or_keep_event_post_apply(serial_rgi, typ, ev); if (err) { cur_thread->free_qev(qev); abandon_worker_thread(rli->sql_driver_thd, cur_thread, &did_enter_cond, &old_stage); return 1; } /* Queue a position update, so that the position will be updated in a reasonable way relative to other events: - If the currently executing events are queued serially for a single thread, the position will only be updated when everything before has completed. - If we are executing multiple independent events in parallel, then at least the position will not be updated until one of them has reached the current point. */ qev->typ= rpl_parallel_thread::queued_event::QUEUED_POS_UPDATE; qev->entry_for_queued= e; } else { qev->rgi= e->current_group_info; } /* Queue the event for processing. */ qev->ir= rli->last_inuse_relaylog; ++qev->ir->queued_count; cur_thread->enqueue(qev); unlock_or_exit_cond(rli->sql_driver_thd, &cur_thread->LOCK_rpl_thread, &did_enter_cond, &old_stage); mysql_cond_signal(&cur_thread->COND_rpl_thread); return 0; }