mariadb/mysys/testhash.c
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

290 lines
6.7 KiB
C

/* Copyright (C) 2000 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 */
/* Test of hash library: big test */
#include <my_global.h>
#include <my_sys.h>
#include <hash.h>
#include <m_string.h>
#define MAX_RECORDS 100000
#define MAX_KEYS 3
static int get_options(int argc, char *argv[]);
static int do_test();
static int rnd(int max_value);
static uint testflag=0,recant=10000,reclength=37;
static uint16 key1[1000];
#ifdef DBUG_OFF
#define hash_check(A) 0
#else
my_bool hash_check(HASH *hash);
#endif
void free_record(void *record);
static uchar *hash2_key(const uchar *rec,uint *length,
my_bool not_used __attribute__((unused)))
{
*length=(uint) (uchar) rec[reclength-1];
return (uchar*) rec;
}
/* main program */
int main(int argc,char *argv[])
{
MY_INIT(argv[0]);
DBUG_PROCESS(argv[0]);
get_options(argc,argv);
exit(do_test());
}
static int do_test()
{
register uint i,j;
uint n1,n2,n3;
uint write_count,update,delete;
ulong pos;
unsigned long key_check;
char *record,*recpos,oldrecord[120],key[10];
HASH hash,hash2;
DBUG_ENTER("do_test");
write_count=update=delete=0;
key_check=0;
bzero((char*) key1,sizeof(key1[0])*1000);
printf("- Creating hash\n");
if (hash_init(&hash, default_charset_info, recant/2, 0, 6, 0, free_record, 0))
goto err;
printf("- Writing records:\n");
for (i=0 ; i < recant ; i++)
{
n1=rnd(1000); n2=rnd(100); n3=rnd(min(recant*5,MAX_RECORDS));
record= (char*) my_malloc(reclength,MYF(MY_FAE));
sprintf(record,"%6d:%4d:%8d:Pos: %4d ",n1,n2,n3,write_count);
if (my_hash_insert(&hash,record))
{
printf("Error: %d in write at record: %d\n",my_errno,i);
goto err;
}
key1[n1]++;
key_check+=n1;
write_count++;
}
if (hash_check(&hash))
{
puts("Heap keys crashed");
goto err;
}
printf("- Delete\n");
for (i=0 ; i < write_count/10 ; i++)
{
for (j=rnd(1000) ; j>0 && key1[j] == 0 ; j--) ;
if (j != 0)
{
sprintf(key,"%6d",j);
if (!(recpos=hash_search(&hash,key,0)))
{
printf("can't find key1: \"%s\"\n",key);
goto err;
}
key1[atoi(recpos)]--;
key_check-=atoi(recpos);
memcpy(oldrecord,recpos,reclength);
if (hash_delete(&hash,recpos))
{
printf("error: %d; can't delete record: \"%s\"\n", my_errno,oldrecord);
goto err;
}
delete++;
if (testflag == 2 && hash_check(&hash))
{
puts("Heap keys crashed");
goto err;
}
}
}
if (hash_check(&hash))
{
puts("Hash keys crashed");
goto err;
}
printf("- Update\n");
for (i=0 ; i < write_count/10 ; i++)
{
n1=rnd(1000); n2=rnd(100); n3=rnd(min(recant*2,MAX_RECORDS));
for (j=rnd(1000) ; j>0 && key1[j] == 0 ; j--) ;
if (j)
{
sprintf(key,"%6d",j);
if (!(recpos=hash_search(&hash,key,0)))
{
printf("can't find key1: \"%s\"\n",key);
goto err;
}
key1[atoi(recpos)]--;
key_check=key_check-atoi(recpos)+n1;
key1[n1]++;
sprintf(recpos,"%6d:%4d:%8d:XXX: %4d ",n1,n2,n3,update);
update++;
if (hash_update(&hash,recpos,key,0))
{
printf("can't update key1: \"%s\"\n",key);
goto err;
}
if (testflag == 3 && hash_check(&hash))
{
printf("Heap keys crashed for %d update\n",update);
goto err;
}
}
}
if (hash_check(&hash))
{
puts("Heap keys crashed");
goto err;
}
for (j=0 ; j < 1000 ; j++)
if (key1[j] > 1)
break;
if (key1[j] > 1)
{
HASH_SEARCH_STATE state;
printf("- Testing identical read\n");
sprintf(key,"%6d",j);
pos=1;
if (!(recpos= hash_first(&hash, key, 0, &state)))
{
printf("can't find key1: \"%s\"\n",key);
goto err;
}
while (hash_next(&hash, key, 0, &state) && pos < (ulong) (key1[j]+10))
pos++;
if (pos != (ulong) key1[j])
{
printf("Found %ld copies of key: %s. Should be %d",pos,key,key1[j]);
goto err;
}
}
printf("- Creating output heap-file 2\n");
if (hash_init(&hash2, default_charset_info, hash.records, 0, 0, hash2_key, free_record,0))
goto err;
printf("- Copying and removing records\n");
pos=0;
while ((recpos=hash_element(&hash,0)))
{
record=(uchar*) my_malloc(reclength,MYF(MY_FAE));
memcpy(record,recpos,reclength);
record[reclength-1]=rnd(5)+1;
if (my_hash_insert(&hash2,record))
{
printf("Got error when inserting record: %*s",reclength,record);
goto err;
}
key_check-=atoi(record);
write_count++;
if (hash_delete(&hash,recpos))
{
printf("Got error when deleting record: %*s",reclength,recpos);
goto err;
}
if (testflag==4)
{
if (hash_check(&hash) || hash_check(&hash2))
{
puts("Hash keys crashed");
goto err;
}
}
pos++;
}
if (hash_check(&hash) || hash_check(&hash2))
{
puts("Hash keys crashed");
goto err;
}
if (key_check != 0)
{
printf("Key check didn't get to 0 (%ld)\n",key_check);
}
printf("\nFollowing test have been made:\n");
printf("Write records: %d\nUpdate records: %d\nDelete records: %d\n", write_count,
update,delete);
hash_free(&hash); hash_free(&hash2);
my_end(MY_GIVE_INFO);
DBUG_RETURN(0);
err:
printf("Got error: %d when using hashing\n",my_errno);
DBUG_RETURN(-1);
} /* main */
/* read options */
/* NOTE! DBUG not initialised - no debugging here! */
static int get_options(int argc, char **argv)
{
char *pos,*progname;
progname= argv[0];
while (--argc >0 && *(pos = *(++argv)) == '-' ) {
switch(*++pos) {
case 'm': /* records */
recant=atoi(++pos);
break;
case 't':
testflag=atoi(++pos); /* testmod */
break;
case 'V':
case 'I':
case '?':
printf("%s Ver 1.0 for %s at %s\n",progname,SYSTEM_TYPE,MACHINE_TYPE);
printf("MySQL AB, by Monty\n\n");
printf("Usage: %s [-?ABIKLWv] [-m#] [-t#]\n",progname);
exit(0);
case '#':
DBUG_PUSH (++pos);
break;
}
}
return 0;
} /* get_options */
/* Get a random number in the interval 0 <= x <= n */
static int rnd(int max_value)
{
return (int) ((rand() & 32767)/32767.0*max_value);
} /* rnd */
void free_record(void *record)
{
my_free(record);
}