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Bug#34043: Server loops excessively in _checkchunk() when safemalloc is enabled

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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.
This commit is contained in:
Davi Arnaut
2010-07-08 18:20:08 -03:00
parent d4cd1f843d
commit a10ae35328
217 changed files with 1012 additions and 1821 deletions
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34
client/mysqlbinlog.cc
View File

@ -68,20 +68,20 @@ TYPELIB base64_output_mode_typelib=
{ array_elements(base64_output_mode_names) - 1, "",
base64_output_mode_names, NULL };
static enum_base64_output_mode opt_base64_output_mode= BASE64_OUTPUT_UNSPEC;
static const char *opt_base64_output_mode_str= NullS;
static const char* database= 0;
static char *opt_base64_output_mode_str= NullS;
static char* database= 0;
static my_bool force_opt= 0, short_form= 0, remote_opt= 0;
static my_bool debug_info_flag, debug_check_flag;
static my_bool force_if_open_opt= 1;
static ulonglong offset = 0;
static const char* host = 0;
static char* host = 0;
static int port= 0;
static uint my_end_arg;
static const char* sock= 0;
#ifdef HAVE_SMEM
static char *shared_memory_base_name= 0;
#endif
static const char* user = 0;
static char* user = 0;
static char* pass = 0;
static char *charset= 0;
@ -96,7 +96,7 @@ static my_time_t start_datetime= 0, stop_datetime= MY_TIME_T_MAX;
static ulonglong rec_count= 0;
static short binlog_flags = 0;
static MYSQL* mysql = NULL;
static const char* dirname_for_local_load= 0;
static char* dirname_for_local_load= 0;
/**
Pointer to the Format_description_log_event of the currently active binlog.
@ -191,7 +191,7 @@ public:
int init()
{
return init_dynamic_array(&file_names, sizeof(File_name_record),
100,100 CALLER_INFO);
100, 100);
}
void init_by_dir_name(const char *dir)
@ -213,7 +213,7 @@ public:
{
if (ptr->fname)
{
my_free(ptr->fname, MYF(MY_WME));
my_free(ptr->fname);
delete ptr->event;
bzero((char *)ptr, sizeof(File_name_record));
}
@ -442,7 +442,7 @@ Exit_status Load_log_processor::process_first_event(const char *bname,
{
error("Could not construct local filename %s%s.",
target_dir_name,bname);
my_free(fname, MYF(0));
my_free(fname);
delete ce;
DBUG_RETURN(ERROR_STOP);
}
@ -458,7 +458,7 @@ Exit_status Load_log_processor::process_first_event(const char *bname,
if (set_dynamic(&file_names, (uchar*)&rec, file_id))
{
error("Out of memory.");
my_free(fname, MYF(0));
my_free(fname);
delete ce;
DBUG_RETURN(ERROR_STOP);
}
@ -822,7 +822,7 @@ Exit_status process_event(PRINT_EVENT_INFO *print_event_info, Log_event *ev,
*/
convert_path_to_forward_slashes((char*) ce->fname);
ce->print(result_file, print_event_info, TRUE);
my_free((char*)ce->fname,MYF(MY_WME));
my_free((void*)ce->fname);
delete ce;
}
else
@ -887,7 +887,7 @@ Exit_status process_event(PRINT_EVENT_INFO *print_event_info, Log_event *ev,
}
if (fname)
my_free(fname, MYF(MY_WME));
my_free(fname);
break;
}
case TABLE_MAP_EVENT:
@ -1222,11 +1222,11 @@ static void warning(const char *format,...)
*/
static void cleanup()
{
my_free(pass,MYF(MY_ALLOW_ZERO_PTR));
my_free((char*) database, MYF(MY_ALLOW_ZERO_PTR));
my_free((char*) host, MYF(MY_ALLOW_ZERO_PTR));
my_free((char*) user, MYF(MY_ALLOW_ZERO_PTR));
my_free((char*) dirname_for_local_load, MYF(MY_ALLOW_ZERO_PTR));
my_free(pass);
my_free(database);
my_free(host);
my_free(user);
my_free(dirname_for_local_load);
delete glob_description_event;
if (mysql)
@ -1306,7 +1306,7 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
argument= (char*) ""; // Don't require password
if (argument)
{
my_free(pass,MYF(MY_ALLOW_ZERO_PTR));
my_free(pass);
char *start=argument;
pass= my_strdup(argument,MYF(MY_FAE));
while (*argument) *argument++= 'x'; /* Destroy argument */