Adjust cost for re-creating a row from the JOIN CACHE

Creating a record from the join cache is faster than getting a row from
the engine (less and simpler code to execute).

Added JOIN_CACHE_ROW_COPY_COST_FACTOR (0.5 for now) as the factor to
take this into account. This is multiplied with ROW_COPY_COST.

Other things:
- Added cost of copying rows to hash join, similar to join_cache joins.

1 files changed, 1 insertions, 0 deletions

diff --git a/mysql-test/main/select_safe.test b/mysql-test/main/select_safe.test
index c76e337cd10..a32405278c2 100644
--- a/mysql-test/main/select_safe.test
+++ b/mysql-test/main/select_safe.test
@@ -60,6 +60,7 @@ analyze table t1;
 insert into t1 values (null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a");
 insert into t1 values (null,"b"),(null,"b"),(null,"c"),(null,"c"),(null,"d"),(null,"d"),(null,"e"),(null,"e"),(null,"a"),(null,"e");
 insert into t1 values (null,"x"),(null,"x"),(null,"y"),(null,"y"),(null,"z"),(null,"z"),(null,"v"),(null,"v"),(null,"a"),(null,"v");
+set @@optimizer_where_compare_cost=0.3;
 explain select STRAIGHT_JOIN * from t1,t1 as t2 where t1.b=t2.b;
 set MAX_SEEKS_FOR_KEY=1;
 explain select STRAIGHT_JOIN * from t1,t1 as t2 where t1.b=t2.b;