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Bug#14640599 MEMORY LEAK WHEN EXECUTING STORED ROUTINE EXCEPTION HANDLER

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When a SP handler is activated, memory is allocated to hold the
MESSAGE_TEXT for the condition that caused the activation.

The problem was that this memory was allocated on the MEM_ROOT belonging
to the stored program. Since this MEM_ROOT is not freed until the
stored program ends, a stored program that causes lots of handler
activations can start using lots of memory. In 5.1 and earlier the
problem did not exist as no MESSAGE_TEXT was allocated if a condition
was raised with a handler present. However, this behavior lead to
a number of other issues such as Bug#23032.

This patch fixes the problem by allocating enough memory for the
necessary MESSAGE_TEXTs in the SP MEM_ROOT when the SP starts and
then re-using this memory each time a handler is activated.
      
This is the 5.5 version of the patch.
This commit is contained in:
Jon Olav Hauglid
2012-10-04 16:15:13 +02:00
parent d68d303118
commit 6c0b206570
3 changed files with 54 additions and 14 deletions
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12
sql/sql_signal.cc
View File

@ -478,7 +478,7 @@ bool Signal_statement::execute(THD *thd)
bool Resignal_statement::execute(THD *thd)
{
MYSQL_ERROR *signaled;
Sql_condition_info *signaled;
int result= TRUE;
DBUG_ENTER("Resignal_statement::execute");
@ -491,15 +491,21 @@ bool Resignal_statement::execute(THD *thd)
DBUG_RETURN(result);
}
MYSQL_ERROR signaled_err(thd->mem_root);
signaled_err.set(signaled->m_sql_errno,
signaled->m_sql_state,
signaled->m_level,
signaled->m_message);
if (m_cond == NULL)
{
/* RESIGNAL without signal_value */
result= raise_condition(thd, signaled);
result= raise_condition(thd, &signaled_err);
DBUG_RETURN(result);
}
/* RESIGNAL with signal_value */
result= raise_condition(thd, signaled);
result= raise_condition(thd, &signaled_err);
DBUG_RETURN(result);
}