WL#1562 (Improving spatial code)

A set of changes improving our RTree indexes and fixed few bugs
found during the tests


myisam/rt_index.c:
  Algorythm for picking the branch to insert was fixed.
  pick_by_perimeter version of the algorythm added (mostly for testing
  purposes)
myisam/rt_index.h:
  minimal size of the page set to 1/3
  It noticeable increases searching performance
myisam/rt_key.c:
  counting of the size of the filled part of the page fixed
  rtree_choose_key moved to rt_index.c
myisam/rt_key.h:
  no need to make rtree_choose_key global
myisam/rt_mbr.c:
  operations for counting the perimeter of MBR added
myisam/rt_mbr.h:
  interface for rtree_perimeter_increase
myisam/rt_split.c:
  my_multi_malloc changed with my_alloca
sql/spatial.cc:
  LINESTRING object can consist of single point

1 files changed, 2 insertions, 44 deletions

diff --git a/myisam/rt_key.c b/myisam/rt_key.c
index f18d13af8d8..0384849e5e7 100644
--- a/myisam/rt_key.c
+++ b/myisam/rt_key.c
@@ -35,7 +35,8 @@ int rtree_add_key(MI_INFO *info, MI_KEYDEF *keyinfo, uchar *key,
   uint page_size = mi_getint(page_buf);
   uint nod_flag = mi_test_if_nod(page_buf);
 
-  if (page_size + key_length + nod_flag <= keyinfo->block_length)  
+  if (page_size + key_length + info->s->base.rec_reflength <=
+      keyinfo->block_length)
   {
     /* split won't be necessary */
     if (nod_flag)
@@ -94,46 +95,3 @@ int rtree_set_key_mbr(MI_INFO *info, MI_KEYDEF *keyinfo, uchar *key,
 
   return rtree_page_mbr(info, keyinfo->seg, info->buff, key, key_length);
 }
-
-
-/*
-  Choose non-leaf better key for insertion
-*/
-
-uchar *rtree_choose_key(MI_INFO *info, MI_KEYDEF *keyinfo, uchar *key, 
-			uint key_length, uchar *page_buf, uint nod_flag)
-{
-  double increase;
-  double best_incr = DBL_MAX;
-  double area;
-  double best_area;
-  uchar *best_key;
-  uchar *k = rt_PAGE_FIRST_KEY(page_buf, nod_flag);
-  uchar *last = rt_PAGE_END(page_buf);
-
-  LINT_INIT(best_area);
-  LINT_INIT(best_key);
-
-  for (; k < last; k = rt_PAGE_NEXT_KEY(k, key_length, nod_flag))
-  {
-    if ((increase = rtree_area_increase(keyinfo->seg, key, k, key_length, 
-                                        &area)) == -1)
-      return NULL;
-    if (increase < best_incr)
-    {
-      best_key = k;
-      best_area = area;
-      best_incr = increase;
-    }
-    else
-    {
-      if ((increase == best_incr) && (area < best_area))
-      {
-        best_key = k;
-        best_area = area;
-        best_incr = increase;
-      }
-    }
-  }
-  return best_key;
-}