bk commit into 5.0 tree (konstantin:1.1913) BUG#7306

[konstantin]

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5.0 repository of kostja. When kostja does a push these changes will
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ChangeSet
  1.1913 05/06/05 21:48:16 konstantin@stripped +1 -0
  á followup patch for the patch for bug#7306: in case we're in
  statement prepare, prevent evaluation of subselects, even if they're
  not correlated.

  sql/item_subselect.cc
    1.108 05/06/05 21:48:10 konstantin@stripped +8 -5
    á followup patch for the patch for bug#7306: in case we're in
    statement prepare, prevent evaluation of subselects, even if they're
    not correlated.

# 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:	konstantin
# Host:	dragonfly.local
# Root:	/opt/local/work/mysql-5.0-7306-final

--- 1.107/sql/item_subselect.cc	2005-06-04 16:33:49 +04:00
+++ 1.108/sql/item_subselect.cc	2005-06-05 21:48:10 +04:00
@@ -182,12 +182,15 @@
   else
     return 1;
   uint8 uncacheable= engine->uncacheable();
-  if (uncacheable)
-  {
+  /*
+    Mark this item as non-const unless this subselect is not correlated.
+    Also temporarily switch off const if we're in prepare (to avoid
+    unneeded query evaluation at prepare).
+  */
+  if (uncacheable || thd->current_arena->is_stmt_prepare())
     const_item_cache= 0;
-    if (uncacheable & UNCACHEABLE_RAND)
-      used_tables_cache|= RAND_TABLE_BIT;
-  }
+  if (uncacheable & UNCACHEABLE_RAND)
+    used_tables_cache|= RAND_TABLE_BIT;
   fixed= 1;
   thd->where= save_where;
   return res;