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MDEV-19826 10.4 seems to crash with "pool-of-threads" (#1370)

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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.
This commit is contained in:
Teemu Ollakka
2019-08-30 08:42:24 +03:00
committed by Jan Lindström
parent d22f8c459f
commit 9487e0b259
17 changed files with 417 additions and 218 deletions
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22
sql/wsrep_schema.cc
View File

@ -29,6 +29,7 @@
#include "wsrep_binlog.h"
#include "wsrep_high_priority_service.h"
#include "wsrep_storage_service.h"
#include "wsrep_thd.h"
#include <string>
#include <sstream>
@ -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);
}