bk commit into 5.1 tree (sergefp:1.2147) BUG#15448

[Sergey Petrunia]

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ChangeSet
  1.2147 06/02/21 00:17:29 sergefp@stripped +1 -0
  BUG#15448 (group_min_max test failure): Don't bypass group-min-max optimizer entry point

  if we've got a tree of type ALWAYS or MAYBE.

  sql/opt_range.cc
    1.202 06/02/21 00:17:17 sergefp@stripped +6 -3
    BUG#15448 (group_min_max test failure): Don't buypass group-min-max optimizer entry
point 
    if we've got a tree of type ALWAYS or MAYBE.
    The effect observed by this bug has been introduced by this cset: 
    ChangeSet 1.1967.5.2 2005/12/26 08:40:09 sergefp@stripped. The cset introduced
PARAM::remove_jump_scans
    which purpose was to avoid making [always unsuccessful] attempts to construct
index_merge for construct 
    index_merge for conditions like "t.key1partX=c1 OR t.key1partY=c2". The effect of this
change was that some
    queries that previously had produced a SEL_TREE representing candidate for
index_merge(X,Y) now started to 
    produce SEL_TREE with type=ALWAYS, and group-min-max analysis for these trees has been
bypassed.
    In this fix we make SEL_TREE with type=ALWAYS to be processed in the same way as
(SEL_TREE*)NULL, its equivalent.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	sergefp
# Host:	pslp.mylan
# Root:	/home/psergey/mysql-5.1-look

--- 1.201/sql/opt_range.cc	2006-02-15 02:01:27 +03:00
+++ 1.202/sql/opt_range.cc	2006-02-21 00:17:17 +03:00
@@ -1951,9 +1951,12 @@
           read_time= (double) HA_POS_ERROR;
           goto free_mem;
         }
-        if (tree->type != SEL_TREE::KEY &&
-            tree->type != SEL_TREE::KEY_SMALLER)
-          goto free_mem;
+        /*
+          If the tree can't be used for range scans, proceed anyway, as we
+          can construct a group-min-max quick select
+        */
+        if (tree->type != SEL_TREE::KEY && tree->type !=
SEL_TREE::KEY_SMALLER)
+          tree= NULL;
       }
     }