Commit bfba296d authored by Jon Olav Hauglid's avatar Jon Olav Hauglid

Bug#14640599 MEMORY LEAK WHEN EXECUTING STORED ROUTINE EXCEPTION HANDLER

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.
parent 30d35590
......@@ -67,19 +67,15 @@ sp_rcontext::~sp_rcontext()
bool sp_rcontext::init(THD *thd)
{
uint handler_count= m_root_parsing_ctx->max_handler_index();
uint i;
in_sub_stmt= thd->in_sub_stmt;
if (init_var_table(thd) || init_var_items())
return TRUE;
if (!(m_raised_conditions= new (thd->mem_root) MYSQL_ERROR[handler_count]))
if (!(m_raised_conditions= new (thd->mem_root) Sql_condition_info[handler_count]))
return TRUE;
for (i= 0; i<handler_count; i++)
m_raised_conditions[i].init(thd->mem_root);
return
!(m_handler=
(sp_handler_t*)thd->alloc(handler_count * sizeof(sp_handler_t))) ||
......@@ -446,13 +442,12 @@ sp_rcontext::exit_handler()
DBUG_VOID_RETURN;
}
MYSQL_ERROR*
sp_rcontext::raised_condition() const
Sql_condition_info* sp_rcontext::raised_condition() const
{
if (m_ihsp > 0)
{
uint hindex= m_in_handler[m_ihsp - 1].index;
MYSQL_ERROR *raised= & m_raised_conditions[hindex];
Sql_condition_info *raised= & m_raised_conditions[hindex];
return raised;
}
......
......@@ -58,6 +58,46 @@ typedef struct
uint index;
} sp_active_handler_t;
class Sql_condition_info : public Sql_alloc
{
public:
/** SQL error code. */
uint m_sql_errno;
/** Error level. */
MYSQL_ERROR::enum_warning_level m_level;
/** SQLSTATE. */
char m_sql_state[SQLSTATE_LENGTH + 1];
/** Text message. */
char m_message[MYSQL_ERRMSG_SIZE];
void set(uint sql_errno, const char* sqlstate,
MYSQL_ERROR::enum_warning_level level,
const char* msg)
{
m_sql_errno= sql_errno;
m_level= level;
memcpy(m_sql_state, sqlstate, SQLSTATE_LENGTH);
m_sql_state[SQLSTATE_LENGTH]= '\0';
strncpy(m_message, msg, MYSQL_ERRMSG_SIZE);
}
void clear()
{
m_sql_errno= 0;
m_level= MYSQL_ERROR::WARN_LEVEL_ERROR;
m_sql_state[0]= '\0';
m_message[0]= '\0';
}
};
/*
This class is a runtime context of a Stored Routine. It is used in an
execution and is intended to contain all dynamic objects (i.e. objects, which
......@@ -146,8 +186,7 @@ class sp_rcontext : public Sql_alloc
MYSQL_ERROR::enum_warning_level level,
const char *msg);
MYSQL_ERROR *
raised_condition() const;
Sql_condition_info *raised_condition() const;
void
push_hstack(uint h);
......@@ -232,7 +271,7 @@ class sp_rcontext : public Sql_alloc
SQL conditions caught by each handler.
This is an array indexed by handler index.
*/
MYSQL_ERROR *m_raised_conditions;
Sql_condition_info *m_raised_conditions;
uint m_hcount; // Stack pointer for m_handler
uint *m_hstack; // Return stack for continue handlers
......
......@@ -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);
}
......
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