1 /*
2 Copyright (c) 2018, 2019 MariaDB
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; version 2 of the License.
7
8 This program is distributed in the hope that it will be useful,
9 but WITHOUT ANY WARRANTY; without even the implied warranty of
10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 GNU General Public License for more details.
12
13 You should have received a copy of the GNU General Public License
14 along with this program; if not, write to the Free Software
15 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA */
16
17 #include "mariadb.h"
18 #include "sql_priv.h"
19 #include "sql_select.h"
20 #include "derived_handler.h"
21
22
23 /**
24 The methods of the Pushdown_derived class.
25
26 The objects of this class are used for pushdown of the derived tables
27 into engines. The main method of the class is Pushdown_derived::execute()
28 that initiates execution of the query specifying a derived by a foreign
29 engine, receives the rows of the result set and put them in a temporary
30 table on the server side.
31
32 The method uses only the functions of the derived_handle interface to do
33 this. The constructor of the class gets this interface as a parameter.
34
35 Currently a derived tables pushed into an engine is always materialized.
36 It could be changed if the cases when the tables is used as driving table.
37 */
38
39
Pushdown_derived(TABLE_LIST * tbl,derived_handler * h)40 Pushdown_derived::Pushdown_derived(TABLE_LIST *tbl, derived_handler *h)
41 : derived(tbl), handler(h)
42 {
43 is_analyze= handler->thd->lex->analyze_stmt;
44 }
45
46
~Pushdown_derived()47 Pushdown_derived::~Pushdown_derived()
48 {
49 delete handler;
50 }
51
52
execute()53 int Pushdown_derived::execute()
54 {
55 int err;
56 THD *thd= handler->thd;
57 TABLE *table= handler->table;
58 TMP_TABLE_PARAM *tmp_table_param= handler->tmp_table_param;
59
60 DBUG_ENTER("Pushdown_query::execute");
61
62 if ((err= handler->init_scan()))
63 goto error;
64
65 if (is_analyze)
66 {
67 handler->end_scan();
68 DBUG_RETURN(0);
69 }
70
71 while (!(err= handler->next_row()))
72 {
73 if (unlikely(thd->check_killed()))
74 {
75 handler->end_scan();
76 DBUG_RETURN(-1);
77 }
78
79 if ((err= table->file->ha_write_tmp_row(table->record[0])))
80 {
81 bool is_duplicate;
82 if (likely(!table->file->is_fatal_error(err, HA_CHECK_DUP)))
83 continue; // Distinct elimination
84
85 if (create_internal_tmp_table_from_heap(thd, table,
86 tmp_table_param->start_recinfo,
87 &tmp_table_param->recinfo,
88 err, 1, &is_duplicate))
89 DBUG_RETURN(1);
90 if (is_duplicate)
91 continue;
92 }
93 }
94
95 if (err != 0 && err != HA_ERR_END_OF_FILE)
96 goto error;
97
98 if ((err= handler->end_scan()))
99 goto error_2;
100
101 DBUG_RETURN(0);
102
103 error:
104 handler->end_scan();
105 error_2:
106 handler->print_error(err, MYF(0));
107 DBUG_RETURN(-1); // Error not sent to client
108 }
109
110
print_error(int error,myf errflag)111 void derived_handler::print_error(int error, myf errflag)
112 {
113 my_error(ER_GET_ERRNO, MYF(0), error, hton_name(ht)->str);
114 }
115
116
set_derived(TABLE_LIST * tbl)117 void derived_handler::set_derived(TABLE_LIST *tbl)
118 {
119 derived= tbl;
120 table= tbl->table;
121 unit= tbl->derived;
122 select= unit->first_select();
123 tmp_table_param= ((select_unit *)(unit->result))->get_tmp_table_param();
124 }
125
126