Subquery cache (MWL#66) added.

libmysqld/Makefile.am:
  The new file added.
mysql-test/r/index_merge_myisam.result:
  subquery_cache optimization option added.
mysql-test/r/myisam_mrr.result:
  subquery_cache optimization option added.
mysql-test/r/subquery_cache.result:
  The subquery cache tests added.
mysql-test/r/subselect3.result:
  Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect3_jcl6.result:
  Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect_no_mat.result:
  subquery_cache optimization option added.
mysql-test/r/subselect_no_opts.result:
  subquery_cache optimization option added.
mysql-test/r/subselect_no_semijoin.result:
  subquery_cache optimization option added.
mysql-test/r/subselect_sj.result:
  subquery_cache optimization option added.
mysql-test/r/subselect_sj_jcl6.result:
  subquery_cache optimization option added.
mysql-test/t/subquery_cache.test:
  The subquery cache tests added.
mysql-test/t/subselect3.test:
  Subquery cache switched off to avoid changing read statistics.
sql/CMakeLists.txt:
  The new file added.
sql/Makefile.am:
  The new files added.
sql/item.cc:
  Expression cache item (Item_cache_wrapper) added.
  Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item.h:
  Expression cache item (Item_cache_wrapper) added.
  Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item_cmpfunc.cc:
  Subquery cache added.
sql/item_cmpfunc.h:
  Subquery cache added.
sql/item_subselect.cc:
  Subquery cache added.
sql/item_subselect.h:
  Subquery cache added.
sql/item_sum.cc:
  Registration of subquery parameters added.
sql/mysql_priv.h:
  subquery_cache optimization option added.
sql/mysqld.cc:
  subquery_cache optimization option added.
sql/opt_range.cc:
  Fix due to subquery cache.
sql/opt_subselect.cc:
  Parameters of the function cahnged.
sql/procedure.h:
  .h file guard added.
sql/sql_base.cc:
  Registration of subquery parameters added.
sql/sql_class.cc:
  Option to allow add indeces to temporary table.
sql/sql_class.h:
  Item iterators added.
  Option to allow add indeces to temporary table.
sql/sql_expression_cache.cc:
  Expression cache for caching subqueries added.
sql/sql_expression_cache.h:
  Expression cache for caching subqueries added.
sql/sql_lex.cc:
  Registration of subquery parameters added.
sql/sql_lex.h:
  Registration of subqueries and subquery parameters added.
sql/sql_select.cc:
  Subquery cache added.
sql/sql_select.h:
  Subquery cache added.
sql/sql_union.cc:
  A new parameter to the function added.
sql/sql_update.cc:
  A new parameter to the function added.
sql/table.cc:
  Procedures to manage temporarty tables index added.
sql/table.h:
  Procedures to manage temporarty tables index added.
storage/maria/ha_maria.cc:
  Fix of handler to allow destoy a table in case of error during the table creation.
storage/maria/ha_maria.h:
  .h file guard added.
storage/myisam/ha_myisam.cc:
  Fix of handler to allow destoy a table in case of error during the table creation.

1 files changed, 51 insertions, 0 deletions

diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index 0c4a6210231..7b19b4874b1 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -1632,6 +1632,8 @@ void st_select_lex::init_query()
   nest_level= 0;
   link_next= 0;
   lock_option= TL_READ_DEFAULT;
+
+  bzero((char*) expr_cache_may_be_used, sizeof(expr_cache_may_be_used));
 }
 
 void st_select_lex::init_select()
@@ -1829,6 +1831,55 @@ void st_select_lex_unit::exclude_tree()
 }
 
 
+/**
+  Register reference to an item which the subqueries depends on
+
+  @param def_sel         select against which the item is resolved
+  @param dependency      reference to the item
+
+  @details
+  This function puts the reference dependency to an item that is either an
+  outer field or an aggregate function resolved against an outer select into
+  the list 'depends_on'. It adds it to the 'depends_on' lists for each
+  subquery between this one and 'def_sel' - the subquery against which the
+  item is resolved.
+*/
+
+void st_select_lex::register_dependency_item(st_select_lex *def_sel,
+                                             Item **dependency)
+{
+  SELECT_LEX *s= this;
+  DBUG_ENTER("st_select_lex::register_dependency_item");
+  DBUG_ASSERT(this != def_sel);
+  DBUG_ASSERT(*dependency);
+  do
+  {
+    /* check duplicates */
+    List_iterator_fast<Item*> li(s->master_unit()->item->depends_on);
+    Item **dep;
+    while ((dep= li++))
+    {
+      if ((*dep)->eq(*dependency, FALSE))
+      {
+         DBUG_PRINT("info", ("dependency %s already present",
+                             ((*dependency)->name ?
+                              (*dependency)->name :
+                              "<no name>")));
+         DBUG_VOID_RETURN;
+      }
+    }
+
+    s->master_unit()->item->depends_on.push_back(dependency);
+    DBUG_PRINT("info", ("depends_on: Select: %d  added: %s",
+                        s->select_number,
+                        ((*dependency)->name ?
+                         (*dependency)->name :
+                         "<no name>")));
+  } while ((s= s->outer_select()) != def_sel);
+  DBUG_VOID_RETURN;
+}
+
+
 /*
   st_select_lex_node::mark_as_dependent mark all st_select_lex struct from 
   this to 'last' as dependent