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().

1 files changed, 2 insertions, 2 deletions

diff --git a/mysys/mf_qsort.c b/mysys/mf_qsort.c
index 3d52d56c952..4b3ecb603a6 100644
--- a/mysys/mf_qsort.c
+++ b/mysys/mf_qsort.c
@@ -91,10 +91,10 @@ typedef struct st_stack
 *****************************************************************************/
 
 #ifdef QSORT_EXTRA_CMP_ARGUMENT
-qsort_t qsort2(void *base_ptr, size_t count, size_t size, qsort2_cmp cmp,
+qsort_t my_qsort2(void *base_ptr, size_t count, size_t size, qsort2_cmp cmp,
 	       void *cmp_argument)
 #else
-qsort_t qsort(void *base_ptr, size_t count, size_t size, qsort_cmp cmp)
+qsort_t my_qsort(void *base_ptr, size_t count, size_t size, qsort_cmp cmp)
 #endif
 {
   char *low, *high, *pivot;