Merge from 10.0-base to 10.0 the feature MDEV-4506: Parallel replication.

The merge is still missing a few hunks related to temporary tables and
InnoDB log file size. The associated code did not seem to exist in
10.0, so the merge of that needs more work. Until this is fixed, there
are a number of test failures as a result.

sql/sql_class.cc

@@ -659,6 +659,17 @@ void thd_set_ha_data(THD *thd, const struct handlerton *hton,
 }
 
 
+/**
+  Allow storage engine to wakeup commits waiting in THD::wait_for_prior_commit.
+  @see thd_wakeup_subsequent_commits() definition in plugin.h
+*/
+extern "C"
+void thd_wakeup_subsequent_commits(THD *thd, int wakeup_error)
+{
+  thd->wakeup_subsequent_commits(wakeup_error);
+}
+
+
 extern "C"
 long long thd_test_options(const THD *thd, long long test_options)
 {
@@ -818,7 +829,7 @@ bool Drop_table_error_handler::handle_condition(THD *thd,
 THD::THD()
    :Statement(&main_lex, &main_mem_root, STMT_CONVENTIONAL_EXECUTION,
               /* statement id */ 0),
-   rli_fake(0), rli_slave(NULL),
+   rli_fake(0), rgi_fake(0), rgi_slave(NULL),
    in_sub_stmt(0), log_all_errors(0),
    binlog_unsafe_warning_flags(0),
    binlog_table_maps(0),
@@ -849,6 +860,7 @@ THD::THD()
 #if defined(ENABLED_DEBUG_SYNC)
    debug_sync_control(0),
 #endif /* defined(ENABLED_DEBUG_SYNC) */
+   wait_for_commit_ptr(0),
     main_da(0, false, false),
    m_stmt_da(&main_da)
 {
@@ -1563,6 +1575,11 @@ THD::~THD()
   dbug_sentry= THD_SENTRY_GONE;
 #endif  
 #ifndef EMBEDDED_LIBRARY
+  if (rgi_fake)
+  {
+    delete rgi_fake;
+    rgi_fake= NULL;
+  }
   if (rli_fake)
   {
     delete rli_fake;
@@ -1570,8 +1587,8 @@ THD::~THD()
   }
   
   mysql_audit_free_thd(this);
-  if (rli_slave)
-    rli_slave->cleanup_after_session();
+  if (rgi_slave)
+    rgi_slave->cleanup_after_session();
 #endif
 
   free_root(&main_mem_root, MYF(0));
@@ -1998,7 +2015,7 @@ void THD::cleanup_after_query()
         which is intended to consume its event (there can be other
         SET statements between them).
     */
-    if ((rli_slave || rli_fake) && is_update_query(lex->sql_command))
+    if ((rgi_slave || rli_fake) && is_update_query(lex->sql_command))
       auto_inc_intervals_forced.empty();
 #endif
   }
@@ -2028,8 +2045,8 @@ void THD::cleanup_after_query()
   m_binlog_invoker= INVOKER_NONE;
 
 #ifndef EMBEDDED_LIBRARY
-  if (rli_slave)
-    rli_slave->cleanup_after_query();
+  if (rgi_slave)
+    rgi_slave->cleanup_after_query();
 #endif
 
   DBUG_VOID_RETURN;
@@ -6016,6 +6033,247 @@ THD::signal_wakeup_ready()
 }
 
 
+void THD::rgi_lock_temporary_tables()
+{
+  mysql_mutex_lock(&rgi_slave->rli->data_lock);
+  temporary_tables= rgi_slave->rli->save_temporary_tables;
+}
+
+void THD::rgi_unlock_temporary_tables()
+{
+  rgi_slave->rli->save_temporary_tables= temporary_tables;
+  mysql_mutex_unlock(&rgi_slave->rli->data_lock);
+}
+
+bool THD::rgi_have_temporary_tables()
+{
+  return rgi_slave->rli->save_temporary_tables != 0;
+}
+
+
+wait_for_commit::wait_for_commit()
+  : subsequent_commits_list(0), next_subsequent_commit(0), waitee(0),
+    opaque_pointer(0),
+    waiting_for_commit(false), wakeup_error(0),
+    wakeup_subsequent_commits_running(false)
+{
+  mysql_mutex_init(key_LOCK_wait_commit, &LOCK_wait_commit, MY_MUTEX_INIT_FAST);
+  mysql_cond_init(key_COND_wait_commit, &COND_wait_commit, 0);
+}
+
+
+wait_for_commit::~wait_for_commit()
+{
+  mysql_mutex_destroy(&LOCK_wait_commit);
+  mysql_cond_destroy(&COND_wait_commit);
+}
+
+
+void
+wait_for_commit::wakeup(int wakeup_error)
+{
+  /*
+    We signal each waiter on their own condition and mutex (rather than using
+    pthread_cond_broadcast() or something like that).
+
+    Otherwise we would need to somehow ensure that they were done
+    waking up before we could allow this THD to be destroyed, which would
+    be annoying and unnecessary.
+
+    Note that wakeup_subsequent_commits2() depends on this function being a
+    full memory barrier (it is, because it takes a mutex lock).
+
+  */
+  mysql_mutex_lock(&LOCK_wait_commit);
+  waiting_for_commit= false;
+  this->wakeup_error= wakeup_error;
+  mysql_mutex_unlock(&LOCK_wait_commit);
+  mysql_cond_signal(&COND_wait_commit);
+}
+
+
+/*
+  Register that the next commit of this THD should wait to complete until
+  commit in another THD (the waitee) has completed.
+
+  The wait may occur explicitly, with the waiter sitting in
+  wait_for_prior_commit() until the waitee calls wakeup_subsequent_commits().
+
+  Alternatively, the TC (eg. binlog) may do the commits of both waitee and
+  waiter at once during group commit, resolving both of them in the right
+  order.
+
+  Only one waitee can be registered for a waiter; it must be removed by
+  wait_for_prior_commit() or unregister_wait_for_prior_commit() before a new
+  one is registered. But it is ok for several waiters to register a wait for
+  the same waitee. It is also permissible for one THD to be both a waiter and
+  a waitee at the same time.
+*/
+void
+wait_for_commit::register_wait_for_prior_commit(wait_for_commit *waitee)
+{
+  waiting_for_commit= true;
+  wakeup_error= 0;
+  DBUG_ASSERT(!this->waitee /* No prior registration allowed */);
+  this->waitee= waitee;
+
+  mysql_mutex_lock(&waitee->LOCK_wait_commit);
+  /*
+    If waitee is in the middle of wakeup, then there is nothing to wait for,
+    so we need not register. This is necessary to avoid a race in unregister,
+    see comments on wakeup_subsequent_commits2() for details.
+  */
+  if (waitee->wakeup_subsequent_commits_running)
+    waiting_for_commit= false;
+  else
+  {
+    /*
+      Put ourself at the head of the waitee's list of transactions that must
+      wait for it to commit first.
+     */
+    this->next_subsequent_commit= waitee->subsequent_commits_list;
+    waitee->subsequent_commits_list= this;
+  }
+  mysql_mutex_unlock(&waitee->LOCK_wait_commit);
+}
+
+
+/*
+  Wait for commit of another transaction to complete, as already registered
+  with register_wait_for_prior_commit(). If the commit already completed,
+  returns immediately.
+*/
+int
+wait_for_commit::wait_for_prior_commit2()
+{
+  mysql_mutex_lock(&LOCK_wait_commit);
+  while (waiting_for_commit)
+    mysql_cond_wait(&COND_wait_commit, &LOCK_wait_commit);
+  mysql_mutex_unlock(&LOCK_wait_commit);
+  waitee= NULL;
+  return wakeup_error;
+}
+
+
+/*
+  Wakeup anyone waiting for us to have committed.
+
+  Note about locking:
+
+  We have a potential race or deadlock between wakeup_subsequent_commits() in
+  the waitee and unregister_wait_for_prior_commit() in the waiter.
+
+  Both waiter and waitee needs to take their own lock before it is safe to take
+  a lock on the other party - else the other party might disappear and invalid
+  memory data could be accessed. But if we take the two locks in different
+  order, we may end up in a deadlock.
+
+  The waiter needs to lock the waitee to delete itself from the list in
+  unregister_wait_for_prior_commit(). Thus wakeup_subsequent_commits() can not
+  hold its own lock while locking waiters, as this could lead to deadlock.
+
+  So we need to prevent unregister_wait_for_prior_commit() running while wakeup
+  is in progress - otherwise the unregister could complete before the wakeup,
+  leading to incorrect spurious wakeup or accessing invalid memory.
+
+  However, if we are in the middle of running wakeup_subsequent_commits(), then
+  there is no need for unregister_wait_for_prior_commit() in the first place -
+  the waiter can just do a normal wait_for_prior_commit(), as it will be
+  immediately woken up.
+
+  So the solution to the potential race/deadlock is to set a flag in the waitee
+  that wakeup_subsequent_commits() is in progress. When this flag is set,
+  unregister_wait_for_prior_commit() becomes just wait_for_prior_commit().
+
+  Then also register_wait_for_prior_commit() needs to check if
+  wakeup_subsequent_commits() is running, and skip the registration if
+  so. This is needed in case a new waiter manages to register itself and
+  immediately try to unregister while wakeup_subsequent_commits() is
+  running. Else the new waiter would also wait rather than unregister, but it
+  would not be woken up until next wakeup, which could be potentially much
+  later than necessary.
+*/
+
+void
+wait_for_commit::wakeup_subsequent_commits2(int wakeup_error)
+{
+  wait_for_commit *waiter;
+
+  mysql_mutex_lock(&LOCK_wait_commit);
+  wakeup_subsequent_commits_running= true;
+  waiter= subsequent_commits_list;
+  subsequent_commits_list= NULL;
+  mysql_mutex_unlock(&LOCK_wait_commit);
+
+  while (waiter)
+  {
+    /*
+      Important: we must grab the next pointer before waking up the waiter;
+      once the wakeup is done, the field could be invalidated at any time.
+    */
+    wait_for_commit *next= waiter->next_subsequent_commit;
+    waiter->wakeup(wakeup_error);
+    waiter= next;
+  }
+
+  /*
+    We need a full memory barrier between walking the list above, and clearing
+    the flag wakeup_subsequent_commits_running below. This barrier is needed
+    to ensure that no other thread will start to modify the list pointers
+    before we are done traversing the list.
+
+    But wait_for_commit::wakeup() does a full memory barrier already (it locks
+    a mutex), so no extra explicit barrier is needed here.
+  */
+  wakeup_subsequent_commits_running= false;
+}
+
+
+/* Cancel a previously registered wait for another THD to commit before us. */
+void
+wait_for_commit::unregister_wait_for_prior_commit2()
+{
+  mysql_mutex_lock(&LOCK_wait_commit);
+  if (waiting_for_commit)
+  {
+    wait_for_commit *loc_waitee= this->waitee;
+    wait_for_commit **next_ptr_ptr, *cur;
+    mysql_mutex_lock(&loc_waitee->LOCK_wait_commit);
+    if (loc_waitee->wakeup_subsequent_commits_running)
+    {
+      /*
+        When a wakeup is running, we cannot safely remove ourselves from the
+        list without corrupting it. Instead we can just wait, as wakeup is
+        already in progress and will thus be immediate.
+
+        See comments on wakeup_subsequent_commits2() for more details.
+      */
+      mysql_mutex_unlock(&loc_waitee->LOCK_wait_commit);
+      while (waiting_for_commit)
+        mysql_cond_wait(&COND_wait_commit, &LOCK_wait_commit);
+    }
+    else
+    {
+      /* Remove ourselves from the list in the waitee. */
+      next_ptr_ptr= &loc_waitee->subsequent_commits_list;
+      while ((cur= *next_ptr_ptr) != NULL)
+      {
+        if (cur == this)
+        {
+          *next_ptr_ptr= this->next_subsequent_commit;
+          break;
+        }
+        next_ptr_ptr= &cur->next_subsequent_commit;
+      }
+      waiting_for_commit= false;
+      mysql_mutex_unlock(&loc_waitee->LOCK_wait_commit);
+    }
+  }
+  mysql_mutex_unlock(&LOCK_wait_commit);
+  this->waitee= NULL;
+}
+
+
 bool Discrete_intervals_list::append(ulonglong start, ulonglong val,
                                  ulonglong incr)
 {