bk commit into 5.0 tree (sergefp:1.2008) BUG#15024

[Sergey Petrunia]

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ChangeSet
  1.2008 05/11/25 20:47:22 sergefp@stripped +1 -0
  BUG#15024: get_best_covering_ror_intersect() tries to build ROR-intersection
  by starting with an empty index set and adding indexes to it until it
  becomes covering. If the set becomes covering after adding the first index,
  return NULL and don't try constructing ROR-intersection of one index (which
  caused a crash)

  sql/opt_range.cc
    1.199 05/11/25 20:47:18 sergefp@stripped +4 -4
    BUG#15024: get_best_covering_ror_intersect() tries to build ROR-intersection
    by starting with an empty index set and adding indexes to it until it
    becomes covering. If the set becomes covering after adding the first index,
    return NULL and don't try constructing ROR-intersection of one index (which
    caused a crash)

# 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:	newbox.mylan
# Root:	/home/psergey/mysql-5.0-bug15204

--- 1.198/sql/opt_range.cc	2005-11-20 21:47:00 +03:00
+++ 1.199/sql/opt_range.cc	2005-11-25 20:47:18 +03:00
@@ -3136,10 +3136,10 @@
     /* F=F-covered by first(I) */
     bitmap_union(&covered_fields, &(*ror_scan_mark)->covered_fields);
     all_covered= bitmap_is_subset(&param->needed_fields, &covered_fields);
-  } while (!all_covered && (++ror_scan_mark < ror_scans_end));
-
-  if (!all_covered)
-    DBUG_RETURN(NULL); /* should not happen actually */
+  } while ((++ror_scan_mark < ror_scans_end) && !all_covered);
+  
+  if (!all_covered || (ror_scan_mark - tree->ror_scans) == 1)
+    DBUG_RETURN(NULL);
 
   /*
     Ok, [tree->ror_scans .. ror_scan) holds covering index_intersection with