bk commit into 4.1 tree (svoj:1.2534) BUG#23312

[Sergey Vojtovich]

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4.1 repository of svoj. When svoj does a push these changes will
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ChangeSet@stripped, 2006-11-02 00:05:02+04:00, svoj@stripped +1 -0
  BUG#23312 - server hangs 'closing tables' with insert delayed,flush
              tables,alter table
  Deadlock could happen if there are delayed insert + flush tables + alter table
  running concurrently.
  
  This is fixed by removing a redundant mutex lock when killing a delayed thread.

  sql/sql_insert.cc@stripped, 2006-11-02 00:02:40+04:00, svoj@stripped +0 -3
    Removed redundant delayed thread mutex lock, that could result in a deadlock.
    LOCK_delayed_insert is sufficient to be sure that no other thread frees delayed
    handler.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	svoj
# Host:	april.(none)
# Root:	/home/svoj/devel/mysql/BUG23312/mysql-4.1-engines

--- 1.172/sql/sql_insert.cc	2006-11-02 00:05:05 +04:00
+++ 1.173/sql/sql_insert.cc	2006-11-02 00:05:05 +04:00
@@ -1181,8 +1181,6 @@ void kill_delayed_threads(void)
   delayed_insert *tmp;
   while ((tmp=it++))
   {
-    /* Ensure that the thread doesn't kill itself while we are looking at it */
-    pthread_mutex_lock(&tmp->mutex);
     tmp->thd.killed=1;
     if (tmp->thd.mysys_var)
     {
@@ -1201,7 +1199,6 @@ void kill_delayed_threads(void)
       }
       pthread_mutex_unlock(&tmp->thd.mysys_var->mutex);
     }
-    pthread_mutex_unlock(&tmp->mutex);
   }
   VOID(pthread_mutex_unlock(&LOCK_delayed_insert)); // For unlink from list
 }