Merging 4.1 to 5.0.

BitKeeper/etc/ignore:
  auto-union
BitKeeper/etc/logging_ok:
  auto-union
client/mysqltest.c:
  Auto merged
configure.in:
  Auto merged
include/my_sys.h:
  Auto merged
include/mysql_com.h:
  Auto merged
libmysql/libmysql.c:
  Auto merged
libmysqld/Makefile.am:
  Auto merged
libmysqld/lib_sql.cc:
  Auto merged
myisam/mi_check.c:
  Auto merged
myisam/myisamchk.c:
  Auto merged
myisam/myisamdef.h:
  Auto merged
mysql-test/r/func_group.result:
  Auto merged
mysql-test/r/func_time.result:
  Auto merged
mysql-test/r/null.result:
  Auto merged
mysql-test/r/query_cache.result:
  Auto merged
mysql-test/r/rpl_server_id2.result:
  Auto merged
mysql-test/r/select.result:
  Auto merged
mysql-test/r/subselect.result:
  Auto merged
mysql-test/r/variables.result:
  Auto merged
mysql-test/t/rpl000015.test:
  Auto merged
mysql-test/t/rpl_error_ignored_table.test:
  Auto merged
mysql-test/t/rpl_log.test:
  Auto merged
mysql-test/t/rpl_log_pos.test:
  Auto merged
mysql-test/t/rpl_max_relay_size.test:
  Auto merged
mysql-test/t/rpl_relayrotate.test:
  Auto merged
mysql-test/t/rpl_rotate_logs.test:
  Auto merged
mysql-test/t/rpl_server_id2.test:
  Auto merged
mysql-test/t/subselect.test:
  Auto merged
mysql-test/t/variables.test:
  Auto merged
mysys/my_pthread.c:
  Auto merged
netware/BUILD/compile-netware-all:
  Auto merged
netware/BUILD/compile-netware-standard:
  Auto merged
netware/BUILD/mwenv:
  Auto merged
netware/Makefile.am:
  Auto merged
netware/my_manage.c:
  Auto merged
netware/my_manage.h:
  Auto merged
netware/mysql_test_run.c:
  Auto merged
scripts/mysql_install_db.sh:
  Auto merged
sql/Makefile.am:
  Auto merged
sql/ha_berkeley.cc:
  Auto merged
sql/ha_berkeley.h:
  Auto merged
sql/ha_innodb.cc:
  Auto merged
sql/ha_innodb.h:
  Auto merged
sql/ha_myisam.cc:
  Auto merged
sql/handler.cc:
  Auto merged
sql/handler.h:
  Auto merged
sql/item.cc:
  Auto merged
sql/item.h:
  Auto merged
sql/item_cmpfunc.cc:
  Auto merged
sql/item_func.cc:
  Auto merged
sql/item_subselect.cc:
  Auto merged
sql/item_subselect.h:
  Auto merged
sql/item_sum.cc:
  Auto merged
sql/item_sum.h:
  Auto merged
sql/item_timefunc.cc:
  Auto merged
sql/lock.cc:
  Auto merged
sql/mysql_priv.h:
  Auto merged
sql/opt_range.cc:
  Auto merged
sql/protocol.cc:
  Auto merged
sql/protocol.h:
  Auto merged
sql/repl_failsafe.cc:
  Auto merged
sql/set_var.cc:
  Auto merged
sql/sql_acl.cc:
  Auto merged
sql/sql_base.cc:
  Auto merged
sql/sql_cache.cc:
  Auto merged
sql/sql_class.cc:
  Auto merged
sql/sql_class.h:
  Auto merged
sql/sql_db.cc:
  Auto merged
sql/sql_insert.cc:
  Auto merged
sql/sql_parse.cc:
  Auto merged
sql/sql_prepare.cc:
  Auto merged
sql/sql_select.h:
  Auto merged
sql/sql_show.cc:
  Auto merged
sql/sql_string.cc:
  Auto merged
sql/sql_string.h:
  Auto merged
sql/sql_table.cc:
  Auto merged
sql/sql_union.cc:
  Auto merged
sql/sql_yacc.yy:
  Auto merged
tests/client_test.c:
  Auto merged

1 files changed, 73 insertions, 14 deletions

diff --git a/sql/sql_union.cc b/sql/sql_union.cc
index 794fbc74c73..73d4616b313 100644
--- a/sql/sql_union.cc
+++ b/sql/sql_union.cc
@@ -41,7 +41,7 @@ int mysql_union(THD *thd, LEX *lex, select_result *result,
 ***************************************************************************/
 
 select_union::select_union(TABLE *table_par)
-  :table(table_par), not_describe(0)
+  :table(table_par)
 {
   bzero((char*) &info,sizeof(info));
   /*
@@ -120,7 +120,7 @@ bool select_union::flush()
 ulong
 st_select_lex_unit::init_prepare_fake_select_lex(THD *thd) 
 {
-  ulong options_tmp= thd->options;
+  ulong options_tmp= thd->options | fake_select_lex->options;
   thd->lex->current_select= fake_select_lex;
   offset_limit_cnt= global_parameters->offset_limit;
   select_limit_cnt= global_parameters->select_limit +
@@ -149,6 +149,8 @@ int st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
   select_result *tmp_result;
   DBUG_ENTER("st_select_lex_unit::prepare");
 
+  describe= test(additional_options & SELECT_DESCRIBE);
+
   /*
     result object should be reassigned even if preparing already done for
     max/min subquery (ALL/ANY optimization)
@@ -156,7 +158,26 @@ int st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
   result= sel_result;
 
   if (prepared)
+  {
+    if (describe)
+    {
+      /* fast reinit for EXPLAIN */
+      for (sl= first_select_in_union(); sl; sl= sl->next_select())
+      {
+	sl->join->result= result;
+	select_limit_cnt= HA_POS_ERROR;
+	offset_limit_cnt= 0;
+	if (!sl->join->procedure &&
+	    result->prepare(sl->join->fields_list, this))
+	{
+	  DBUG_RETURN(1);
+	}
+	sl->join->select_options|= SELECT_DESCRIBE;
+	sl->join->reinit();
+      }
+    }
     DBUG_RETURN(0);
+  }
   prepared= 1;
   res= 0;
   
@@ -169,8 +190,9 @@ int st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
   {
     if (!(tmp_result= union_result= new select_union(0)))
       goto err;
-    union_result->not_describe= 1;
     union_result->tmp_table_param.init();
+    if (describe)
+      tmp_result= sel_result;
   }
   else
   {
@@ -329,20 +351,24 @@ int st_select_lex_unit::exec()
   ulonglong add_rows=0;
   DBUG_ENTER("st_select_lex_unit::exec");
 
-  if (executed && !uncacheable)
+  if (executed && !uncacheable && !describe)
     DBUG_RETURN(0);
   executed= 1;
   
-  if (uncacheable || !item || !item->assigned())
+  if (uncacheable || !item || !item->assigned() || describe)
   {
-    if (optimized && item && item->assigned())
+    if (optimized && item)
     {
-      item->assigned(0); // We will reinit & rexecute unit
-      item->reset();
-      table->file->delete_all_rows();
+      if (item->assigned())
+      {
+        item->assigned(0); // We will reinit & rexecute unit
+        item->reset();
+        table->file->delete_all_rows();
+      }
+      /* re-enabling indexes for next subselect iteration */
+      if (union_distinct && table->file->enable_indexes(HA_KEY_SWITCH_ALL))
+        DBUG_ASSERT(1);
     }
-    if (union_distinct) // for subselects
-      table->file->extra(HA_EXTRA_CHANGE_KEY_TO_UNIQUE);
     for (SELECT_LEX *sl= select_cursor; sl; sl= sl->next_select())
     {
       ha_rows records_at_start= 0;
@@ -352,7 +378,7 @@ int st_select_lex_unit::exec()
 	res= sl->join->reinit();
       else
       {
-	if (sl != global_parameters)
+	if (sl != global_parameters && !describe)
 	{
 	  offset_limit_cnt= sl->offset_limit;
 	  select_limit_cnt= sl->select_limit+sl->offset_limit;
@@ -364,7 +390,7 @@ int st_select_lex_unit::exec()
 	    We can't use LIMIT at this stage if we are using ORDER BY for the
 	    whole query
 	  */
-	  if (sl->order_list.first)
+	  if (sl->order_list.first || describe)
 	    select_limit_cnt= HA_POS_ERROR;
 	  else
 	    select_limit_cnt= sl->select_limit+sl->offset_limit;
@@ -394,7 +420,11 @@ int st_select_lex_unit::exec()
 	records_at_start= table->file->records;
 	sl->join->exec();
         if (sl == union_distinct)
-          table->file->extra(HA_EXTRA_CHANGE_KEY_TO_DUP);
+	{
+	  if (table->file->disable_indexes(HA_KEY_SWITCH_ALL))
+	    DBUG_RETURN(1);
+	  table->no_keyread=1;
+	}
 	res= sl->join->error;
 	offset_limit_cnt= sl->offset_limit;
 	if (!res && union_result->flush())
@@ -557,3 +587,32 @@ void st_select_lex_unit::reinit_exec_mechanism()
   }
 #endif
 }
+
+
+/*
+  change select_result object of unit
+
+  SYNOPSIS
+    st_select_lex_unit::change_result()
+    result	new select_result object
+    old_result	old select_result object
+
+  RETURN
+    0 - OK
+    -1 - error
+*/
+
+int st_select_lex_unit::change_result(select_subselect *result,
+				      select_subselect *old_result)
+{
+  int res= 0;
+  for (SELECT_LEX *sl= first_select_in_union(); sl; sl= sl->next_select())
+  {
+    if (sl->join && sl->join->result == old_result)
+      if ((res= sl->join->change_result(result)))
+	return (res);
+  }
+  if (fake_select_lex && fake_select_lex->join)
+    res= fake_select_lex->join->change_result(result);
+  return (res);
+}