From 9487e0b259e7f410f5f93ae59851be60d6a5112c Mon Sep 17 00:00:00 2001 From: Teemu Ollakka Date: Fri, 30 Aug 2019 08:42:24 +0300 Subject: MDEV-19826 10.4 seems to crash with "pool-of-threads" (#1370) MariaDB 10.4 was crashing when thread-handling was set to pool-of-threads and wsrep was enabled. There were two apparent reasons for the crash: - Connection handling in threadpool_common.cc was missing calls to control wsrep client state. - Thread specific storage which contains thread variables (THR_KEY_mysys) was not handled appropriately by wsrep patch when pool-of-threads was configured. This patch addresses the above issues in the following way: - Wsrep client state open/close was moved in thd_prepare_connection() and end_connection() to have common handling for one-thread-per-connection and pool-of-threads. - Thread local storage handling in wsrep patch was reworked by introducing set of wsrep_xxx_threadvars() calls which replace calls to THD store_globals()/reset_globals() and deal with thread handling specifics internally. Wsrep-lib was updated to version which relaxes internal concurrency related sanity checks. Rollback code from wsrep_rollback_process() was extracted to separate calls for better readability. Post rollback thread was removed as it was completely unused. --- sql/wsrep_schema.cc | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'sql/wsrep_schema.cc') diff --git a/sql/wsrep_schema.cc b/sql/wsrep_schema.cc index 064b6cf9f46..066ea124fb7 100644 --- a/sql/wsrep_schema.cc +++ b/sql/wsrep_schema.cc @@ -29,6 +29,7 @@ #include "wsrep_binlog.h" #include "wsrep_high_priority_service.h" #include "wsrep_storage_service.h" +#include "wsrep_thd.h" #include #include @@ -145,13 +146,13 @@ public: : m_orig_thd(orig_thd) , m_cur_thd(cur_thd) { - m_orig_thd->reset_globals(); - m_cur_thd->store_globals(); + wsrep_reset_threadvars(m_orig_thd); + wsrep_store_threadvars(m_cur_thd); } ~thd_context_switch() { - m_cur_thd->reset_globals(); - m_orig_thd->store_globals(); + wsrep_reset_threadvars(m_cur_thd); + wsrep_store_threadvars(m_orig_thd); } private: THD *m_orig_thd; @@ -595,7 +596,8 @@ static void wsrep_init_thd_for_schema(THD *thd) thd->variables.option_bits |= OPTION_LOG_OFF; /* Read committed isolation to avoid gap locking */ thd->variables.tx_isolation= ISO_READ_COMMITTED; - thd->store_globals(); + wsrep_assign_from_threadvars(thd); + wsrep_store_threadvars(thd); } int Wsrep_schema::init() @@ -1123,6 +1125,7 @@ int Wsrep_schema::replay_transaction(THD* orig_thd, THD thd(next_thread_id(), true); thd.thread_stack= (orig_thd ? orig_thd->thread_stack : (char*) &thd); + wsrep_assign_from_threadvars(&thd); Wsrep_schema_impl::wsrep_off wsrep_off(&thd); Wsrep_schema_impl::binlog_off binlog_off(&thd); @@ -1228,6 +1231,7 @@ int Wsrep_schema::recover_sr_transactions(THD *orig_thd) THD storage_thd(next_thread_id(), true); storage_thd.thread_stack= (orig_thd ? orig_thd->thread_stack : (char*) &storage_thd); + wsrep_assign_from_threadvars(&storage_thd); TABLE* frag_table= 0; TABLE* cluster_table= 0; Wsrep_storage_service storage_service(&storage_thd); @@ -1333,12 +1337,7 @@ int Wsrep_schema::recover_sr_transactions(THD *orig_thd) transaction_id))) { DBUG_ASSERT(wsrep::starts_transaction(flags)); - THD* thd= new THD(next_thread_id(), true); - thd->thread_stack= (char*)&storage_thd; - - thd->real_id= pthread_self(); - - applier= new Wsrep_applier_service(thd); + applier = wsrep_create_streaming_applier(&storage_thd, "recovery"); server_state.start_streaming_applier(server_id, transaction_id, applier); applier->start_transaction(wsrep::ws_handle(transaction_id, 0), @@ -1364,6 +1363,7 @@ int Wsrep_schema::recover_sr_transactions(THD *orig_thd) Wsrep_schema_impl::end_scan(frag_table); Wsrep_schema_impl::finish_stmt(&storage_thd); trans_commit(&storage_thd); + storage_thd.set_mysys_var(0); out: DBUG_RETURN(ret); } -- cgit v1.2.1