MDEV-17096 Pushdown of simple derived tables to storage engines

Resolved the problem of forming a proper query string for FEDERATEDX.
Added test cases.

Cleanup of extra spaces.

14 files changed, 233 insertions, 67 deletions

diff --git a/mysql-test/suite/federated/federatedx_create_handlers.result b/mysql-test/suite/federated/federatedx_create_handlers.result
index fdad44c1b95..a25b0191e55 100644
--- a/mysql-test/suite/federated/federatedx_create_handlers.result
+++ b/mysql-test/suite/federated/federatedx_create_handlers.result
@@ -10,7 +10,7 @@ Warnings:
 Note	1051	Unknown table 'federated.t1'
 CREATE TABLE federated.t1 (
 id int(20) NOT NULL,
-name varchar(16) NOT NULL default ''  
+name varchar(16) NOT NULL default ''
 )
 DEFAULT CHARSET=latin1;
 INSERT INTO federated.t1 VALUES
@@ -19,7 +19,7 @@ DROP TABLE IF EXISTS federated.t2;
 Warnings:
 Note	1051	Unknown table 'federated.t2'
 CREATE TABLE federated.t2 (
-name varchar(16) NOT NULL default ''  
+name varchar(16) NOT NULL default ''
 )
 DEFAULT CHARSET=latin1;
 INSERT INTO federated.t2 VALUES
@@ -30,7 +30,7 @@ Warnings:
 Note	1051	Unknown table 'federated.t1'
 CREATE TABLE federated.t1 (
 id int(20) NOT NULL,
-name varchar(16) NOT NULL default ''  
+name varchar(16) NOT NULL default ''
 )
 ENGINE="FEDERATED" DEFAULT CHARSET=latin1
 CONNECTION='mysql://root@127.0.0.1:SLAVE_PORT/federated/t1';
@@ -38,7 +38,7 @@ DROP TABLE IF EXISTS federated.t2;
 Warnings:
 Note	1051	Unknown table 'federated.t2'
 CREATE TABLE federated.t2 (
-name varchar(16) NOT NULL default ''  
+name varchar(16) NOT NULL default ''
 )
 ENGINE="FEDERATED" DEFAULT CHARSET=latin1
 CONNECTION='mysql://root@127.0.0.1:SLAVE_PORT/federated/t2';
@@ -123,7 +123,7 @@ ANALYZE
   }
 }
 CREATE TABLE federated.t3 (
-name varchar(16) NOT NULL default ''  
+name varchar(16) NOT NULL default ''
 )
 DEFAULT CHARSET=latin1;
 INSERT INTO federated.t3 VALUES
@@ -190,7 +190,114 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_f
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	7	7.00	100.00	100.00	
 1	PRIMARY	<derived2>	ref	key0	key0	18	federated.t3.name	2	0.00	100.00	100.00	
 2	PUSHED DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
-DROP TABLE federated.t1, federated.t2;
+SELECT *
+FROM federated.t3, (SELECT t1.name FROM federated.t1
+WHERE id IN (SELECT count(*)
+FROM federated.t2 GROUP BY name)) t
+WHERE federated.t3.name=t.name;
+name	name
+xxx	xxx
+EXPLAIN
+SELECT *
+FROM federated.t3, (SELECT t1.name FROM federated.t1
+WHERE id IN (SELECT count(*)
+FROM federated.t2 GROUP BY name)) t
+WHERE federated.t3.name=t.name;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	7	
+1	PRIMARY	<derived2>	ref	key0	key0	18	federated.t3.name	2	
+2	PUSHED DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+3	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	7	Using temporary
+ANALYZE FORMAT=JSON
+SELECT *
+FROM federated.t3, (SELECT t1.name FROM federated.t1
+WHERE id IN (SELECT count(*)
+FROM federated.t2 GROUP BY name)) t
+WHERE federated.t3.name=t.name;
+ANALYZE
+{
+  "query_block": {
+    "select_id": 1,
+    "r_loops": 1,
+    "r_total_time_ms": "REPLACED",
+    "table": {
+      "table_name": "t3",
+      "access_type": "ALL",
+      "r_loops": 1,
+      "rows": 7,
+      "r_rows": 7,
+      "r_total_time_ms": "REPLACED",
+      "filtered": 100,
+      "r_filtered": 100
+    },
+    "table": {
+      "table_name": "<derived2>",
+      "access_type": "ref",
+      "possible_keys": ["key0"],
+      "key": "key0",
+      "key_length": "18",
+      "used_key_parts": ["name"],
+      "ref": ["federated.t3.name"],
+      "r_loops": 7,
+      "rows": 2,
+      "r_rows": 0,
+      "r_total_time_ms": "REPLACED",
+      "filtered": 100,
+      "r_filtered": 100,
+      "materialized": {
+        "query_block": {
+          "select_id": 2,
+          "table": {
+            "message": "Pushed derived"
+          },
+          "subqueries": [
+            {
+              "query_block": {
+                "select_id": 3,
+                "temporary_table": {
+                  "table": {
+                    "table_name": "t2",
+                    "access_type": "ALL",
+                    "r_loops": 0,
+                    "rows": 7,
+                    "r_rows": null,
+                    "filtered": 100,
+                    "r_filtered": null
+                  }
+                }
+              }
+            }
+          ]
+        }
+      }
+    }
+  }
+}
+SELECT t.id, federated.t3.name
+FROM federated.t3,
+( SELECT * FROM federated.t1 WHERE id < 3
+UNION
+SELECT * FROM federated.t1 WHERE id >= 5) t
+WHERE federated.t3.name=t.name;
+id	name
+5	yyy
+7	yyy
+5	yyy
+7	yyy
+5	yyy
+7	yyy
+EXPLAIN
+SELECT t.id, federated.t3.name
+FROM federated.t3,
+( SELECT * FROM federated.t1 WHERE id < 3
+UNION
+SELECT * FROM federated.t1 WHERE id >= 5) t
+WHERE federated.t3.name=t.name;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	7	
+1	PRIMARY	<derived2>	ref	key0	key0	18	federated.t3.name	2	
+2	PUSHED DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+DROP TABLE federated.t1, federated.t2, federated.t3;
 connection slave;
 DROP TABLE federated.t1, federated.t2;
 connection default;
diff --git a/mysql-test/suite/federated/federatedx_create_handlers.test b/mysql-test/suite/federated/federatedx_create_handlers.test
index 0e586dad0c1..21539b61c8a 100644
--- a/mysql-test/suite/federated/federatedx_create_handlers.test
+++ b/mysql-test/suite/federated/federatedx_create_handlers.test
@@ -7,7 +7,7 @@ DROP TABLE IF EXISTS federated.t1;
 
 CREATE TABLE federated.t1 (
   id int(20) NOT NULL,
-  name varchar(16) NOT NULL default ''  
+  name varchar(16) NOT NULL default ''
 )
 DEFAULT CHARSET=latin1;
 
@@ -17,7 +17,7 @@ INSERT INTO federated.t1 VALUES
 DROP TABLE IF EXISTS federated.t2;
 
 CREATE TABLE federated.t2 (
-  name varchar(16) NOT NULL default ''  
+  name varchar(16) NOT NULL default ''
 )
 DEFAULT CHARSET=latin1;
 
@@ -33,7 +33,7 @@ DROP TABLE IF EXISTS federated.t1;
 eval
 CREATE TABLE federated.t1 (
   id int(20) NOT NULL,
-  name varchar(16) NOT NULL default ''  
+  name varchar(16) NOT NULL default ''
 )
 ENGINE="FEDERATED" DEFAULT CHARSET=latin1
 CONNECTION='mysql://root@127.0.0.1:$SLAVE_MYPORT/federated/t1';
@@ -43,7 +43,7 @@ DROP TABLE IF EXISTS federated.t2;
 --replace_result $SLAVE_MYPORT SLAVE_PORT
 eval
 CREATE TABLE federated.t2 (
-  name varchar(16) NOT NULL default ''  
+  name varchar(16) NOT NULL default ''
 )
 ENGINE="FEDERATED" DEFAULT CHARSET=latin1
 CONNECTION='mysql://root@127.0.0.1:$SLAVE_MYPORT/federated/t2';
@@ -76,11 +76,12 @@ SELECT id FROM federated.t1 WHERE id < 5;
 ANALYZE
 SELECT id FROM federated.t1 WHERE id < 5;
 
+--source include/analyze-format.inc
 ANALYZE FORMAT=JSON
 SELECT id FROM federated.t1 WHERE id < 5;
 
 CREATE TABLE federated.t3 (
-  name varchar(16) NOT NULL default ''  
+  name varchar(16) NOT NULL default ''
 )
 DEFAULT CHARSET=latin1;
 
@@ -89,26 +90,63 @@ INSERT INTO federated.t3 VALUES
 
 SELECT *
 FROM federated.t3, (SELECT * FROM federated.t1 WHERE id > 3) t
-WHERE federated.t3.name=t.name; 
+WHERE federated.t3.name=t.name;
 
 EXPLAIN
 SELECT *
 FROM federated.t3, (SELECT * FROM federated.t1 WHERE id > 3) t
-WHERE federated.t3.name=t.name; 
+WHERE federated.t3.name=t.name;
 
 EXPLAIN FORMAT=JSON
 SELECT *
 FROM federated.t3, (SELECT * FROM federated.t1 WHERE id > 3) t
-WHERE federated.t3.name=t.name; 
+WHERE federated.t3.name=t.name;
 
 ANALYZE
 SELECT *
 FROM federated.t3, (SELECT * FROM federated.t1 WHERE id > 3) t
-WHERE federated.t3.name=t.name; 
+WHERE federated.t3.name=t.name;
 
-DROP TABLE federated.t1, federated.t2;
+SELECT *
+FROM federated.t3, (SELECT t1.name FROM federated.t1
+                    WHERE id IN (SELECT count(*)
+                                 FROM federated.t2 GROUP BY name)) t
+WHERE federated.t3.name=t.name;
 
-connection slave; 
+EXPLAIN
+SELECT *
+FROM federated.t3, (SELECT t1.name FROM federated.t1
+                    WHERE id IN (SELECT count(*)
+                                 FROM federated.t2 GROUP BY name)) t
+WHERE federated.t3.name=t.name;
+
+--source include/analyze-format.inc
+ANALYZE FORMAT=JSON
+SELECT *
+FROM federated.t3, (SELECT t1.name FROM federated.t1
+                    WHERE id IN (SELECT count(*)
+                                 FROM federated.t2 GROUP BY name)) t
+WHERE federated.t3.name=t.name;
+
+SELECT t.id, federated.t3.name
+FROM federated.t3,
+     ( SELECT * FROM federated.t1 WHERE id < 3
+       UNION
+       SELECT * FROM federated.t1 WHERE id >= 5) t
+WHERE federated.t3.name=t.name;
+
+EXPLAIN
+SELECT t.id, federated.t3.name
+FROM federated.t3,
+     ( SELECT * FROM federated.t1 WHERE id < 3
+       UNION
+       SELECT * FROM federated.t1 WHERE id >= 5) t
+WHERE federated.t3.name=t.name;
+
+
+DROP TABLE federated.t1, federated.t2, federated.t3;
+
+connection slave;
 DROP TABLE federated.t1, federated.t2;
 
 connection default;
diff --git a/sql/derived_handler.cc b/sql/derived_handler.cc
index 561c18a5657..1fa5e94a1d4 100644
--- a/sql/derived_handler.cc
+++ b/sql/derived_handler.cc
@@ -16,7 +16,7 @@ void derived_handler::set_derived(TABLE_LIST *tbl)
 
 Pushdown_derived::Pushdown_derived(TABLE_LIST *tbl, derived_handler *h)
  : derived(tbl), handler(h)
-{ 
+{
   is_analyze= handler->thd->lex->analyze_stmt;
 }
 
@@ -42,7 +42,7 @@ int Pushdown_derived::execute()
     handler->end_scan();
     DBUG_RETURN(0);
   }
-  
+
   while (!(err= handler->next_row()))
   {
     if (unlikely(thd->check_killed()))
@@ -50,7 +50,7 @@ int Pushdown_derived::execute()
       handler->end_scan();
       DBUG_RETURN(-1);
     }
-  
+
     if ((err= table->file->ha_write_tmp_row(table->record[0])))
     {
       bool is_duplicate;
@@ -81,4 +81,4 @@ error_2:
   handler->print_error(err, MYF(0));
   DBUG_RETURN(-1);                              // Error not sent to client
 }
-  
+
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 4cd63042558..821f51ffaf5 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -1215,8 +1215,13 @@ bool Item_in_optimizer::eval_not_null_tables(void *opt_arg)
 
 void Item_in_optimizer::print(String *str, enum_query_type query_type)
 {
-   restore_first_argument();
-   Item_func::print(str, query_type);
+  if (query_type & QT_PARSABLE)
+    args[1]->print(str, query_type);
+  else
+  {
+     restore_first_argument();
+     Item_func::print(str, query_type);
+  }
 }
 
 
diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index 0ace59fd2fc..7aa2ed489a3 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -3272,7 +3272,8 @@ out:
 
 void Item_in_subselect::print(String *str, enum_query_type query_type)
 {
-  if (test_strategy(SUBS_IN_TO_EXISTS))
+  if (test_strategy(SUBS_IN_TO_EXISTS) &&
+      !(query_type & QT_PARSABLE))
     str->append(STRING_WITH_LEN("<exists>"));
   else
   {
@@ -3499,7 +3500,8 @@ Item_allany_subselect::select_transformer(JOIN *join)
 
 void Item_allany_subselect::print(String *str, enum_query_type query_type)
 {
-  if (test_strategy(SUBS_IN_TO_EXISTS))
+  if (test_strategy(SUBS_IN_TO_EXISTS) &&
+      !(query_type & QT_PARSABLE))
     str->append(STRING_WITH_LEN("<exists>"));
   else
   {
diff --git a/sql/mysqld.h b/sql/mysqld.h
index 3d056fb95c7..320dedc4671 100644
--- a/sql/mysqld.h
+++ b/sql/mysqld.h
@@ -745,6 +745,8 @@ enum enum_query_type
   /// SHOW CREATE {VIEW|PROCEDURE|FUNCTION} and other cases where the
   /// original representation is required, should set this flag.
   QT_ITEM_ORIGINAL_FUNC_NULLIF= (1 << 7),
+  /// good for parsing
+  QT_PARSABLE= (1 << 8),
 
   /// This value means focus on readability, not on ability to parse back, etc.
   QT_EXPLAIN=           QT_TO_SYSTEM_CHARSET |
diff --git a/sql/select_handler.cc b/sql/select_handler.cc
index 17475f4907d..9a8d3914b21 100644
--- a/sql/select_handler.cc
+++ b/sql/select_handler.cc
@@ -6,7 +6,7 @@
 
 Pushdown_select::Pushdown_select(SELECT_LEX *sel, select_handler *h)
   : select(sel), handler(h)
-{ 
+{
   is_analyze= handler->thd->lex->analyze_stmt;
 }
 
@@ -35,7 +35,7 @@ bool Pushdown_select::init()
     DBUG_RETURN(true);
   if (handler->table->fill_item_list(&result_columns))
     DBUG_RETURN(true);
-  DBUG_RETURN(false);  
+  DBUG_RETURN(false);
 }
 
 bool Pushdown_select::send_result_set_metadata()
@@ -74,7 +74,7 @@ bool Pushdown_select::send_data()
     protocol->remove_last_row();
     DBUG_RETURN(true);
   }
- 
+
   thd->inc_sent_row_count(1);
 
   if (thd->vio_ok())
@@ -88,13 +88,13 @@ bool Pushdown_select::send_eof()
   THD *thd= handler->thd;
   DBUG_ENTER("Pushdown_select::send_eof");
 
-  /* 
+  /*
     Don't send EOF if we're in error condition (which implies we've already
     sent or are sending an error)
   */
   if (thd->is_error())
     DBUG_RETURN(true);
-  ::my_eof(thd);  
+  ::my_eof(thd);
   DBUG_RETURN(false);
 }
 
@@ -113,10 +113,10 @@ int Pushdown_select::execute()
     handler->end_scan();
     DBUG_RETURN(0);
   }
-  
+
   if (send_result_set_metadata())
     DBUG_RETURN(-1);
-  
+
   while (!(err= handler->next_row()))
   {
     if (thd->check_killed() || send_data())
diff --git a/sql/select_handler.h b/sql/select_handler.h
index 3b1347efed6..19a1883f6c7 100644
--- a/sql/select_handler.h
+++ b/sql/select_handler.h
@@ -20,9 +20,9 @@ class select_handler
 
   select_handler(THD *thd_arg, handlerton *ht_arg)
     : thd(thd_arg), ht(ht_arg), table(0) {}
-  
-  virtual ~select_handler() {} 
- 
+
+  virtual ~select_handler() {}
+
   /*
     Functions to scan the select result set.
     All these returns 0 if ok, error code in case of error.
@@ -32,7 +32,7 @@ class select_handler
   virtual int init_scan() = 0;
 
   /*
-    Put the next produced row of the result set in table->record[0] 
+    Put the next produced row of the result set in table->record[0]
     and return 0. Return HA_ERR_END_OF_FILE if there are no more rows,
     return other error number in case of fatal error.
   */
@@ -40,7 +40,7 @@ class select_handler
 
   /* Finish scanning */
   virtual int end_scan() = 0;
-  
+
   /* Report errors */
   virtual void print_error(int error, myf errflag) = 0;
 };
diff --git a/sql/sql_derived.cc b/sql/sql_derived.cc
index 9ad22dde9c6..564049e59e1 100644
--- a/sql/sql_derived.cc
+++ b/sql/sql_derived.cc
@@ -385,7 +385,7 @@ bool mysql_derived_merge(THD *thd, LEX *lex, TABLE_LIST *derived)
     DBUG_RETURN(FALSE);
   }
 
-  if ((derived->dt_handler= derived->find_derived_handler(thd)))
+  if (derived->dt_handler)
   {
     derived->change_refs_to_fields();
     derived->set_materialized_derived();
@@ -820,6 +820,24 @@ bool mysql_derived_prepare(THD *thd, LEX *lex, TABLE_LIST *derived)
   if (derived->is_derived() && derived->is_merged_derived())
     first_select->mark_as_belong_to_derived(derived);
 
+  derived->dt_handler= derived->find_derived_handler(thd);
+  if (derived->dt_handler)
+  {
+    char query_buff[4096];
+    String derived_query(query_buff, sizeof(query_buff), thd->charset());
+    derived_query.length(0);
+    derived->derived->print(&derived_query,
+                            enum_query_type(QT_VIEW_INTERNAL | 
+                                            QT_ITEM_ORIGINAL_FUNC_NULLIF |
+                                            QT_PARSABLE));
+    if (!thd->make_lex_string(&derived->derived_spec,
+                              derived_query.ptr(), derived_query.length()))
+    {
+      delete derived->dt_handler;
+      derived->dt_handler= NULL;
+    }
+  }
+
 exit:
   /* Hide "Unknown column" or "Unknown function" error */
   if (derived->view)
@@ -912,19 +930,17 @@ bool mysql_derived_optimize(THD *thd, LEX *lex, TABLE_LIST *derived)
     DBUG_RETURN(FALSE);
   }
 
-  if (derived->is_materialized_derived() && !derived->dt_handler)
-    derived->dt_handler= derived->find_derived_handler(thd);
-  if (derived->dt_handler)
+  if (derived->is_materialized_derived() && derived->dt_handler)
   {
     if (!(derived->pushdown_derived=
             new (thd->mem_root) Pushdown_derived(derived, derived->dt_handler)))
     {
       delete derived->dt_handler;
-      derived->dt_handler= NULL; 
-      DBUG_RETURN(1);
+      derived->dt_handler= NULL;
+      DBUG_RETURN(TRUE);
     }
-  }    
-  
+  }
+
   lex->current_select= first_select;
 
   if (unit->is_unit_op())
@@ -1136,7 +1152,7 @@ bool mysql_derived_fill(THD *thd, LEX *lex, TABLE_LIST *derived)
     if (unit->executed)
       DBUG_RETURN(FALSE);
     res= derived->pushdown_derived->execute();
-    unit->executed= true; 
+    unit->executed= true;
     delete derived->pushdown_derived;
       DBUG_RETURN(res);
   }
diff --git a/sql/sql_explain.cc b/sql/sql_explain.cc
index b8d80c7c59c..7bb04fe6be4 100644
--- a/sql/sql_explain.cc
+++ b/sql/sql_explain.cc
@@ -339,7 +339,7 @@ int print_explain_row(select_result_sink *result,
 
   if (!select_type[0])
     return 0;
-  
+
   item_list.push_back(new (mem_root) Item_int(thd, (int32) select_number),
                       mem_root);
   item_list.push_back(new (mem_root) Item_string_sys(thd, select_type),
@@ -756,7 +756,7 @@ int Explain_select::print_explain(Explain_query *query,
   {
      print_explain_message_line(output, explain_flags, is_analyze,
                                 select_id /*select number*/,
-                                select_type, 
+                                select_type,
                                 NULL, /* rows */
                                 NULL);
   }
@@ -1225,7 +1225,7 @@ int Explain_table_access::print_explain(select_result_sink *output, uint8 explai
 {
   THD *thd= output->thd;
   MEM_ROOT *mem_root= thd->mem_root;
-  
+
   List<Item> item_list;
   Item *item_null= new (mem_root) Item_null(thd);
   
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 7cbbdfeee4f..e9040e197e0 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -4044,7 +4044,7 @@ void JOIN::exec_inner()
     not the case.
   */
   if (exec_const_order_group_cond.elements &&
-      !(select_options & SELECT_DESCRIBE) && 
+      !(select_options & SELECT_DESCRIBE) &&
       !select_lex->pushdown_select)
   {
     List_iterator_fast<Item> const_item_it(exec_const_order_group_cond);
@@ -4300,7 +4300,7 @@ mysql_select(THD *thd,
       DBUG_RETURN(TRUE);
     }
   }
-      
+
   if ((err= join->optimize()))
   {
     goto err;					// 1
@@ -4322,7 +4322,7 @@ mysql_select(THD *thd,
     select_lex->where= join->conds_history;
     select_lex->having= join->having_history;
   }
-    
+
 err:
 
   if (select_lex->pushdown_select)
@@ -25885,7 +25885,7 @@ bool mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, select_result *result)
         res= unit->exec();
     }
   }
-  else 
+  else
   {
     thd->lex->current_select= first;
     unit->set_limit(unit->global_parameters());
diff --git a/sql/table.h b/sql/table.h
index 7b88344830b..f7bcdaa58b2 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -2137,6 +2137,7 @@ struct TABLE_LIST
   bool is_derived_with_recursive_reference;
   bool block_handle_derived;
   derived_handler *dt_handler;
+  LEX_CSTRING derived_spec;
   Pushdown_derived *pushdown_derived;
   ST_SCHEMA_TABLE *schema_table;        /* Information_schema table */
   st_select_lex	*schema_select_lex;
diff --git a/storage/federatedx/federatedx_pushdown.cc b/storage/federatedx/federatedx_pushdown.cc
index bfe421c8ab2..c53b35976f7 100644
--- a/storage/federatedx/federatedx_pushdown.cc
+++ b/storage/federatedx/federatedx_pushdown.cc
@@ -38,14 +38,14 @@ create_federatedx_derived_handler(THD* thd, TABLE_LIST *derived)
         return 0;
     }
   }
-  
+
   handler= new ha_federatedx_derived_handler(thd, derived);
 
   return handler;
 }
 
 
-/* 
+/*
   Implementation class of the derived_handler interface for FEDERATEDX:
   class implementation
 */
@@ -62,7 +62,6 @@ ha_federatedx_derived_handler::~ha_federatedx_derived_handler() {}
 
 int ha_federatedx_derived_handler::init_scan()
 {
-  char query_buff[4096];
   THD *thd;
   int rc= 0;
 
@@ -76,12 +75,8 @@ int ha_federatedx_derived_handler::init_scan()
   txn= h->get_txn(thd);
   if ((rc= txn->acquire(share, thd, TRUE, iop)))
     DBUG_RETURN(rc);
-  
-  String derived_query(query_buff, sizeof(query_buff), thd->charset());
-  derived_query.length(0);
-  derived->derived->print(&derived_query, QT_ORDINARY);
-  
-  if ((*iop)->query(derived_query.ptr(), derived_query.length()))
+
+  if ((*iop)->query(derived->derived_spec.str, derived->derived_spec.length))
     goto err;
 
   stored_result= (*iop)->store_result();
@@ -93,7 +88,7 @@ int ha_federatedx_derived_handler::init_scan()
 err:
   DBUG_RETURN(HA_FEDERATEDX_ERROR_WITH_REMOTE_SYSTEM);
 }
-      
+
 int ha_federatedx_derived_handler::next_row()
 {
   int rc;
@@ -167,7 +162,7 @@ create_federatedx_select_handler(THD* thd, SELECT_LEX *sel)
   return handler;
 }
 
-/* 
+/*
   Implementation class of the select_handler interface for FEDERATEDX:
   class implementation
 */
@@ -175,7 +170,7 @@ create_federatedx_select_handler(THD* thd, SELECT_LEX *sel)
 ha_federatedx_select_handler::ha_federatedx_select_handler(THD *thd,
                                                            SELECT_LEX *sel)
   : select_handler(thd, federatedx_hton),
-    share(NULL), txn(NULL), iop(NULL), stored_result(NULL) 
+    share(NULL), txn(NULL), iop(NULL), stored_result(NULL)
 {
   select= sel;
 }
diff --git a/storage/federatedx/federatedx_pushdown.h b/storage/federatedx/federatedx_pushdown.h
index 961571b972c..673abcfc68d 100644
--- a/storage/federatedx/federatedx_pushdown.h
+++ b/storage/federatedx/federatedx_pushdown.h
@@ -17,7 +17,7 @@
 #include "derived_handler.h"
 #include "select_handler.h"
 
-/* 
+/*
   Implementation class of the derived_handler interface for FEDERATEDX:
   class declaration
 */
@@ -40,7 +40,7 @@ public:
 };
 
 
-/* 
+/*
   Implementation class of the select_handler interface for FEDERATEDX:
   class declaration
 */