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f56dd32bf7
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.
158 lines
5.7 KiB
C++
158 lines
5.7 KiB
C++
/* Copyright (C) 2005 MySQL AB, 2008-2009 Sun Microsystems, Inc
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#ifndef _sql_plugin_h
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#define _sql_plugin_h
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/*
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the following #define adds server-only members to enum_mysql_show_type,
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that is defined in plugin.h
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*/
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#define SHOW_always_last SHOW_KEY_CACHE_LONG, \
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SHOW_KEY_CACHE_LONGLONG, SHOW_LONG_STATUS, SHOW_DOUBLE_STATUS, \
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SHOW_HAVE, SHOW_MY_BOOL, SHOW_HA_ROWS, SHOW_SYS, \
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SHOW_LONG_NOFLUSH, SHOW_LONGLONG_STATUS, SHOW_LEX_STRING
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#include <mysql/plugin.h>
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#undef SHOW_always_last
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#include "m_string.h" /* LEX_STRING */
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#include "my_alloc.h" /* MEM_ROOT */
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class sys_var;
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enum SHOW_COMP_OPTION { SHOW_OPTION_YES, SHOW_OPTION_NO, SHOW_OPTION_DISABLED};
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#include <my_sys.h>
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#ifdef DBUG_OFF
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#define plugin_ref_to_int(A) A
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#define plugin_int_to_ref(A) A
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#else
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#define plugin_ref_to_int(A) (A ? A[0] : NULL)
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#define plugin_int_to_ref(A) &(A)
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#endif
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/*
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the following flags are valid for plugin_init()
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*/
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#define PLUGIN_INIT_SKIP_DYNAMIC_LOADING 1
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#define PLUGIN_INIT_SKIP_PLUGIN_TABLE 2
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#define PLUGIN_INIT_SKIP_INITIALIZATION 4
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#define INITIAL_LEX_PLUGIN_LIST_SIZE 16
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typedef enum enum_mysql_show_type SHOW_TYPE;
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typedef struct st_mysql_show_var SHOW_VAR;
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typedef struct st_mysql_lex_string LEX_STRING;
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#define MYSQL_ANY_PLUGIN -1
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/*
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different values of st_plugin_int::state
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though they look like a bitmap, plugin may only
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be in one of those eigenstates, not in a superposition of them :)
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It's a bitmap, because it makes it easier to test
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"whether the state is one of those..."
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*/
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#define PLUGIN_IS_FREED 1
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#define PLUGIN_IS_DELETED 2
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#define PLUGIN_IS_UNINITIALIZED 4
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#define PLUGIN_IS_READY 8
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#define PLUGIN_IS_DYING 16
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#define PLUGIN_IS_DISABLED 32
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/* A handle for the dynamic library containing a plugin or plugins. */
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struct st_plugin_dl
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{
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LEX_STRING dl;
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void *handle;
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struct st_mysql_plugin *plugins;
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int version;
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uint ref_count; /* number of plugins loaded from the library */
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};
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/* A handle of a plugin */
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struct st_plugin_int
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{
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LEX_STRING name;
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struct st_mysql_plugin *plugin;
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struct st_plugin_dl *plugin_dl;
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uint state;
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uint ref_count; /* number of threads using the plugin */
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void *data; /* plugin type specific, e.g. handlerton */
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MEM_ROOT mem_root; /* memory for dynamic plugin structures */
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sys_var *system_vars; /* server variables for this plugin */
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bool is_mandatory; /* If true then plugin must not fail to load */
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};
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/*
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See intern_plugin_lock() for the explanation for the
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conditionally defined plugin_ref type
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*/
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#ifdef DBUG_OFF
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typedef struct st_plugin_int *plugin_ref;
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#define plugin_decl(pi) ((pi)->plugin)
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#define plugin_dlib(pi) ((pi)->plugin_dl)
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#define plugin_data(pi,cast) ((cast)((pi)->data))
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#define plugin_name(pi) (&((pi)->name))
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#define plugin_state(pi) ((pi)->state)
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#define plugin_equals(p1,p2) ((p1) == (p2))
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#else
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typedef struct st_plugin_int **plugin_ref;
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#define plugin_decl(pi) ((pi)[0]->plugin)
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#define plugin_dlib(pi) ((pi)[0]->plugin_dl)
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#define plugin_data(pi,cast) ((cast)((pi)[0]->data))
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#define plugin_name(pi) (&((pi)[0]->name))
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#define plugin_state(pi) ((pi)[0]->state)
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#define plugin_equals(p1,p2) ((p1) && (p2) && (p1)[0] == (p2)[0])
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#endif
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typedef int (*plugin_type_init)(struct st_plugin_int *);
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extern char *opt_plugin_load;
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extern char *opt_plugin_dir_ptr;
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extern char opt_plugin_dir[FN_REFLEN];
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extern const LEX_STRING plugin_type_names[];
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extern int plugin_init(int *argc, char **argv, int init_flags);
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extern void plugin_shutdown(void);
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void add_plugin_options(DYNAMIC_ARRAY *options, MEM_ROOT *mem_root);
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extern bool plugin_is_ready(const LEX_STRING *name, int type);
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#define my_plugin_lock_by_name(A,B,C) plugin_lock_by_name(A,B,C)
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#define my_plugin_lock_by_name_ci(A,B,C) plugin_lock_by_name(A,B,C)
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#define my_plugin_lock(A,B) plugin_lock(A,B)
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#define my_plugin_lock_ci(A,B) plugin_lock(A,B)
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extern plugin_ref plugin_lock(THD *thd, plugin_ref *ptr);
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extern plugin_ref plugin_lock_by_name(THD *thd, const LEX_STRING *name,
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int type);
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extern void plugin_unlock(THD *thd, plugin_ref plugin);
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extern void plugin_unlock_list(THD *thd, plugin_ref *list, uint count);
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extern bool mysql_install_plugin(THD *thd, const LEX_STRING *name,
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const LEX_STRING *dl);
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extern bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name);
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extern bool plugin_register_builtin(struct st_mysql_plugin *plugin);
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extern void plugin_thdvar_init(THD *thd);
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extern void plugin_thdvar_cleanup(THD *thd);
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extern SHOW_COMP_OPTION plugin_status(const char *name, int len, size_t type);
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typedef my_bool (plugin_foreach_func)(THD *thd,
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plugin_ref plugin,
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void *arg);
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#define plugin_foreach(A,B,C,D) plugin_foreach_with_mask(A,B,C,PLUGIN_IS_READY,D)
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extern bool plugin_foreach_with_mask(THD *thd, plugin_foreach_func *func,
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int type, uint state_mask, void *arg);
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#endif
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