mariadb/sql/sql_profile.h
Davi Arnaut f56dd32bf7 Bug#34043: Server loops excessively in _checkchunk() when safemalloc is enabled
Essentially, the problem is that safemalloc is excruciatingly
slow as it checks all allocated blocks for overrun at each
memory management primitive, yielding a almost exponential
slowdown for the memory management functions (malloc, realloc,
free). The overrun check basically consists of verifying some
bytes of a block for certain magic keys, which catches some
simple forms of overrun. Another minor problem is violation
of aliasing rules and that its own internal list of blocks
is prone to corruption.

Another issue with safemalloc is rather the maintenance cost
as the tool has a significant impact on the server code.
Given the magnitude of memory debuggers available nowadays,
especially those that are provided with the platform malloc
implementation, maintenance of a in-house and largely obsolete
memory debugger becomes a burden that is not worth the effort
due to its slowness and lack of support for detecting more
common forms of heap corruption.

Since there are third-party tools that can provide the same
functionality at a lower or comparable performance cost, the
solution is to simply remove safemalloc. Third-party tools
can provide the same functionality at a lower or comparable
performance cost. 

The removal of safemalloc also allows a simplification of the
malloc wrappers, removing quite a bit of kludge: redefinition
of my_malloc, my_free and the removal of the unused second
argument of my_free. Since free() always check whether the
supplied pointer is null, redudant checks are also removed.

Also, this patch adds unit testing for my_malloc and moves
my_realloc implementation into the same file as the other
memory allocation primitives.

client/mysqldump.c:
  Pass my_free directly as its signature is compatible with the
  callback type -- which wasn't the case for free_table_ent.
2010-07-08 18:20:08 -03:00

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/* Copyright (C) 2007 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#ifndef _SQL_PROFILE_H
#define _SQL_PROFILE_H
class Item;
struct TABLE_LIST;
class THD;
typedef struct st_field_info ST_FIELD_INFO;
typedef struct st_schema_table ST_SCHEMA_TABLE;
extern ST_FIELD_INFO query_profile_statistics_info[];
int fill_query_profile_statistics_info(THD *thd, TABLE_LIST *tables, Item *cond);
int make_profile_table_for_show(THD *thd, ST_SCHEMA_TABLE *schema_table);
#define PROFILE_NONE (uint)0
#define PROFILE_CPU (uint)(1<<0)
#define PROFILE_MEMORY (uint)(1<<1)
#define PROFILE_BLOCK_IO (uint)(1<<2)
#define PROFILE_CONTEXT (uint)(1<<3)
#define PROFILE_PAGE_FAULTS (uint)(1<<4)
#define PROFILE_IPC (uint)(1<<5)
#define PROFILE_SWAPS (uint)(1<<6)
#define PROFILE_SOURCE (uint)(1<<16)
#define PROFILE_ALL (uint)(~0)
#if defined(ENABLED_PROFILING)
#include "sql_priv.h"
#include "unireg.h"
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif
class PROF_MEASUREMENT;
class QUERY_PROFILE;
class PROFILING;
/**
Implements a persistent FIFO using server List method names. Not
thread-safe. Intended to be used on thread-local data only.
*/
template <class T> class Queue
{
private:
struct queue_item
{
T *payload;
struct queue_item *next, *previous;
};
struct queue_item *first, *last;
public:
Queue()
{
elements= 0;
first= last= NULL;
}
void empty()
{
struct queue_item *i, *after_i;
for (i= first; i != NULL; i= after_i)
{
after_i= i->next;
my_free(i);
}
elements= 0;
}
ulong elements; /* The count of items in the Queue */
void push_back(T *payload)
{
struct queue_item *new_item;
new_item= (struct queue_item *) my_malloc(sizeof(struct queue_item), MYF(0));
new_item->payload= payload;
if (first == NULL)
first= new_item;
if (last != NULL)
{
DBUG_ASSERT(last->next == NULL);
last->next= new_item;
}
new_item->previous= last;
new_item->next= NULL;
last= new_item;
elements++;
}
T *pop()
{
struct queue_item *old_item= first;
T *ret= NULL;
if (first == NULL)
{
DBUG_PRINT("warning", ("tried to pop nonexistent item from Queue"));
return NULL;
}
ret= old_item->payload;
if (first->next != NULL)
first->next->previous= NULL;
else
last= NULL;
first= first->next;
my_free(old_item);
elements--;
return ret;
}
bool is_empty()
{
DBUG_ASSERT(((elements > 0) && (first != NULL)) || ((elements == 0) || (first == NULL)));
return (elements == 0);
}
void *new_iterator()
{
return first;
}
void *iterator_next(void *current)
{
return ((struct queue_item *) current)->next;
}
T *iterator_value(void *current)
{
return ((struct queue_item *) current)->payload;
}
};
/**
A single entry in a single profile.
*/
class PROF_MEASUREMENT
{
private:
friend class QUERY_PROFILE;
friend class PROFILING;
QUERY_PROFILE *profile;
char *status;
#ifdef HAVE_GETRUSAGE
struct rusage rusage;
#elif defined(_WIN32)
FILETIME ftKernel, ftUser;
#endif
char *function;
char *file;
unsigned int line;
double time_usecs;
char *allocated_status_memory;
void set_label(const char *status_arg, const char *function_arg,
const char *file_arg, unsigned int line_arg);
void clean_up();
PROF_MEASUREMENT();
PROF_MEASUREMENT(QUERY_PROFILE *profile_arg, const char *status_arg);
PROF_MEASUREMENT(QUERY_PROFILE *profile_arg, const char *status_arg,
const char *function_arg,
const char *file_arg, unsigned int line_arg);
~PROF_MEASUREMENT();
void collect();
};
/**
The full profile for a single query, and includes multiple PROF_MEASUREMENT
objects.
*/
class QUERY_PROFILE
{
private:
friend class PROFILING;
PROFILING *profiling;
query_id_t profiling_query_id; /* Session-specific id. */
char *query_source;
PROF_MEASUREMENT *profile_start;
PROF_MEASUREMENT *profile_end;
Queue<PROF_MEASUREMENT> entries;
QUERY_PROFILE(PROFILING *profiling_arg, const char *status_arg);
~QUERY_PROFILE();
void set_query_source(char *query_source_arg, uint query_length_arg);
/* Add a profile status change to the current profile. */
void new_status(const char *status_arg,
const char *function_arg,
const char *file_arg, unsigned int line_arg);
/* Reset the contents of this profile entry. */
void reset();
/* Show this profile. This is called by PROFILING. */
bool show(uint options);
};
/**
Profiling state for a single THD; contains multiple QUERY_PROFILE objects.
*/
class PROFILING
{
private:
friend class PROF_MEASUREMENT;
friend class QUERY_PROFILE;
/*
Not the system query_id, but a counter unique to profiling.
*/
query_id_t profile_id_counter;
THD *thd;
bool keeping;
bool enabled;
QUERY_PROFILE *current;
QUERY_PROFILE *last;
Queue<QUERY_PROFILE> history;
query_id_t next_profile_id() { return(profile_id_counter++); }
public:
PROFILING();
~PROFILING();
void set_query_source(char *query_source_arg, uint query_length_arg);
void start_new_query(const char *initial_state= "starting");
void discard_current_query();
void finish_current_query();
void status_change(const char *status_arg,
const char *function_arg,
const char *file_arg, unsigned int line_arg);
inline void set_thd(THD *thd_arg) { thd= thd_arg; };
/* SHOW PROFILES */
bool show_profiles();
/* ... from INFORMATION_SCHEMA.PROFILING ... */
int fill_statistics_info(THD *thd, TABLE_LIST *tables, Item *cond);
};
# endif /* HAVE_PROFILING */
#endif /* _SQL_PROFILE_H */