summaryrefslogtreecommitdiffstats
path: root/sql/derived_handler.cc
diff options
context:
space:
mode:
Diffstat (limited to 'sql/derived_handler.cc')
-rw-r--r--sql/derived_handler.cc113
1 files changed, 113 insertions, 0 deletions
diff --git a/sql/derived_handler.cc b/sql/derived_handler.cc
new file mode 100644
index 00000000..cddd1200
--- /dev/null
+++ b/sql/derived_handler.cc
@@ -0,0 +1,113 @@
+/*
+ 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)
+{
+}
+
+
+
+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_derived::execute");
+
+ if ((err= handler->init_scan()))
+ goto error;
+
+ 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();
+}
+