bzr push into mysql-trunk branch (ole.john.aske:3879 to 3880) WL#5940

[Ole John Aske]

 3880 Ole John Aske	2012-04-25
      Updated WL#5940 with latest findings from main cluster branch (mysql-5.5-cluster-7.2)
      
      Only try to 'make_pushed_join()' if there are multiple tables in query.
            
      We want to keep a 'fast track' through the optimizer for simple, single table queries.
      Thus we should avoid possible overhead from finding join-pushable parts of the query
      if there are only a single table. 

    modified:
      sql/sql_optimizer.cc
 3879 Ole John Aske	2012-04-25
      WL#5940 update: When applying the WL#5940 patchset to this branch on top of a fresh trunk pull,
      I didn't realize that Cluster specific components was recently merged into trunk - including
      ha_ndbcluster implementing the pushed join extension ha_ndbcluster::test_push_flag().
      
      This reintroduced a previous version of that method handling the now obsolete 
      HA_PUSH_NO_ORDERED_INDEX. This is removed by this fix.

    modified:
      sql/ha_ndbcluster.cc
=== modified file 'sql/sql_optimizer.cc'
--- a/sql/sql_optimizer.cc	2012-03-30 06:52:25 +0000
+++ b/sql/sql_optimizer.cc	2012-04-25 11:52:33 +0000
@@ -953,7 +953,9 @@ JOIN::optimize()
    * information it need for later execution of pushed queries.
    *
    * Currently pushed joins are only implemented by NDB.
+   * It only make sense to try pushing if > 1 tables.
    */
+  if ((tables-const_tables) > 1)
   {
     const AQP::Join_plan plan(this);
     if (ha_make_pushed_joins(thd, &plan))

No bundle (reason: useless for push emails).