mariadb/sql/sql_array.h
unknown ce8bf087b0 Fix for bug #31207: Test "join_nested" shows different strategy on IA64
CPUs / Intel's ICC compile

The bug is a combination of two problems:

1. IA64/ICC MySQL binaries use glibc's qsort(), not the one in mysys.

2. The order relation implemented by join_tab_cmp() is not transitive,
i.e. it is possible to choose such a, b and c that (a < b) && (b < c)
but (c < a). This implies that result of a sort using the relation
implemented by join_tab_cmp() depends on the order in which
elements are compared, i.e. the result is implementation-specific. Since
choose_plan() uses qsort() to pre-sort the
join tables using join_tab_cmp() as a compare function, the results of
the sorting may vary depending on qsort() implementation.

It is neither possible nor important to implement a better ordering
algorithm in join_tab_cmp(). Therefore the only way to fix it is to
force our own qsort() to be used by renaming it to my_qsort(), so we don't depend
on linker to decide that.

This patch also "fixes" bug #20530: qsort redefinition violates the
standard.


include/my_sys.h:
  Renamed qsort() and qsort2() to my_qsort() and my_qsort2(). Since
  previously we relied on stdlib.h to provide a declaration for qsort(), a
  separate declaration for my_qsort() is now required.
libmysql/Makefile.shared:
  Added mf_qsort.c to libmysql, since my_lib.c now uses my_qsort() instead of qsort().
myisam/ft_boolean_search.c:
  Replaced qsort2() with my_qsort2().
myisam/ft_nlq_search.c:
  Replaced qsort2() with my_qsort2().
myisam/myisampack.c:
  Replaced qsort() with my_qsort().
myisam/sort.c:
  Replaced qsort2() with my_qsort2().
mysys/mf_keycache.c:
  Replaced qsort() with my_qsort().
mysys/mf_qsort.c:
  Renamed qsort() to my_qsort() and qsort2() to my_qsort2().
mysys/mf_sort.c:
  Replaced qsort2() with my_qsort2().
mysys/my_lib.c:
  Replaced qsort() with my_qsort().
mysys/queues.c:
  Replaced qsort2() with my_qsort2().
sql/item_cmpfunc.cc:
  Replaced qsort2() with my_qsort2().
sql/item_cmpfunc.h:
  Replaced qsort2() with my_qsort2().
sql/opt_range.cc:
  Replaced qsort() with my_qsort().
sql/records.cc:
  Replaced qsort() with my_qsort().
sql/sql_acl.cc:
  Replaced qsort() with my_qsort().
sql/sql_array.h:
  Replaced qsort() with my_qsort().
sql/sql_help.cc:
  Replaced qsort() with my_qsort().
sql/sql_select.cc:
  Replaced qsort() with my_qsort().
sql/examples/ha_tina.cc:
  Replaced qsort() with my_qsort().
sql/sql_table.cc:
  Replaced qsort() with my_qsort().
2007-10-17 20:08:58 +04:00

68 lines
1.5 KiB
C++

/* Copyright (C) 2003 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 */
#include <my_sys.h>
/*
A typesafe wrapper around DYNAMIC_ARRAY
*/
template <class Elem> class Dynamic_array
{
DYNAMIC_ARRAY array;
public:
Dynamic_array(uint prealloc=16, uint increment=16)
{
my_init_dynamic_array(&array, sizeof(Elem), prealloc, increment);
}
Elem& at(int idx)
{
return *(((Elem*)array.buffer) + idx);
}
Elem *front()
{
return (Elem*)array.buffer;
}
Elem *back()
{
return ((Elem*)array.buffer) + array.elements;
}
bool append(Elem &el)
{
return (insert_dynamic(&array, (gptr)&el));
}
int elements()
{
return array.elements;
}
~Dynamic_array()
{
delete_dynamic(&array);
}
typedef int (*CMP_FUNC)(const Elem *el1, const Elem *el2);
void sort(CMP_FUNC cmp_func)
{
my_qsort(array.buffer, array.elements, sizeof(Elem), (qsort_cmp)cmp_func);
}
};