1 files changed, 125 insertions, 0 deletions
diff --git a/sql/derived_handler.cc b/sql/derived_handler.cc
new file mode 100644
index 00000000..f48b95cb
--- /dev/null
+++ b/sql/derived_handler.cc
@@ -0,0 +1,125 @@
+/*
+   Copyright (c) 2018, 2019 MariaDB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA */
+
+#include "mariadb.h"
+#include "sql_priv.h"
+#include "sql_select.h"
+#include "derived_handler.h"
+
+
+/**
+  The methods of the Pushdown_derived class.
+
+  The objects of this class are used for pushdown of the derived tables
+  into engines. The main  method of the class is Pushdown_derived::execute()
+  that initiates execution of the query specifying a derived by a foreign
+  engine, receives the rows of the result set and put them in a temporary
+  table on the server side.
+
+  The method uses only the functions of the derived_handle interface to do
+  this. The constructor of the class gets this interface as a parameter.
+
+  Currently a derived tables pushed into an engine is always materialized.
+  It could be changed if the cases when the tables is used as driving table.
+*/
+
+
+Pushdown_derived::Pushdown_derived(TABLE_LIST *tbl, derived_handler *h)
+ : derived(tbl), handler(h)
+{
+  is_analyze= handler->thd->lex->analyze_stmt;
+}
+
+
+Pushdown_derived::~Pushdown_derived()
+{
+  delete handler;
+}
+
+
+int Pushdown_derived::execute()
+{
+  int err;
+  THD *thd= handler->thd;
+  TABLE *table= handler->table;
+  TMP_TABLE_PARAM *tmp_table_param= handler->tmp_table_param;
+
+  DBUG_ENTER("Pushdown_query::execute");
+
+  if ((err= handler->init_scan()))
+    goto error;
+
+  if (is_analyze)
+  {
+    handler->end_scan();
+    DBUG_RETURN(0);
+  }
+
+  while (!(err= handler->next_row()))
+  {
+    if (unlikely(thd->check_killed()))
+    {
+      handler->end_scan();
+      DBUG_RETURN(-1);
+    }
+
+    if ((err= table->file->ha_write_tmp_row(table->record[0])))
+    {
+      bool is_duplicate;
+      if (likely(!table->file->is_fatal_error(err, HA_CHECK_DUP)))
+        continue;                           // Distinct elimination
+
+      if (create_internal_tmp_table_from_heap(thd, table,
+                                              tmp_table_param->start_recinfo,
+                                              &tmp_table_param->recinfo,
+                                              err, 1, &is_duplicate))
+        DBUG_RETURN(1);
+      if (is_duplicate)
+        continue;
+    }
+  }
+
+  if (err != 0 && err != HA_ERR_END_OF_FILE)
+    goto error;
+
+  if ((err= handler->end_scan()))
+    goto error_2;
+
+  DBUG_RETURN(0);
+
+error:
+  handler->end_scan();
+error_2:
+  handler->print_error(err, MYF(0));
+  DBUG_RETURN(-1);                              // Error not sent to client
+}
+
+
+void derived_handler::print_error(int error, myf errflag)
+{
+  my_error(ER_GET_ERRNO, MYF(0), error, hton_name(ht)->str);
+}
+
+
+void derived_handler::set_derived(TABLE_LIST *tbl)
+{
+  derived= tbl;
+  table= tbl->table;
+  unit= tbl->derived;
+  select= unit->first_select();
+  tmp_table_param= ((select_unit *)(unit->result))->get_tmp_table_param();
+}
+