MDEV-33281 Implement optimizer hints

Forbid adding optimizer hints to view definitions.
In the case when optimizer hints are added to the view definition
at a `CREATE (OR REPLACE) VIEW`/`ALTER VIEW` statement, a warning is
generated and the hints are ignored.

This commit also disables ps-protocol for test cases where
`Unresolved table/index name` warnings are generated. The reason
for this is such warnings are generated during both PREPARE
and EXECUTE stages. Since opt_hints.test has `--enable_prepare_warnings`,
running it with `--ps-protocol` causes duplication of warning messages

mysql-test/main/lowercase_table.test

@@ -220,6 +220,7 @@ SET NAMES utf8mb4;
 CREATE TABLE t1 (a INT);
 INSERT INTO t1 VALUES (1), (2);
 
+--enable_prepare_warnings
 # Test that aliases are accent sensitive with lowercase-table-names=1
 # Test that table names in hints are also accent sensitive
 SELECT /*+BKA(a) BKA(å)*/ a.a FROM t1 a, t1 å;
@@ -229,6 +230,7 @@ SELECT /*+BKA(a) BKA(å)*/ a.a FROM t1 a, t1 å;
 SELECT a.a, A.a FROM t1 a, t1 A;
 # Test that table names in hints are also case insensitive
 SELECT /*+BKA(a) BKA(A)*/ a.a FROM t1 a;
+--disable_prepare_warnings
 
 DROP TABLE t1;
 

mysql-test/main/opt_hints.result

@@ -1070,7 +1070,69 @@ i
 Warnings:
 Warning	4202	Hint NO_ICP(`t1`@`q1` `PRIMARY`) is ignored as conflicting/duplicated
 DROP TABLE t1;
-# WL#8016 Parser for optimizer hints
+#
+# Hints inside views are not supported
+#
+CREATE TABLE t1 (a INT, INDEX idx_a(a));
+INSERT INTO t1 VALUES (1),(2);
+CREATE VIEW v1 AS SELECT /*+ NO_MRR(t1 idx_a) */ a FROM t1;
+Warnings:
+Warning	4206	Optimizer hints are not supported inside view definitions
+SELECT * FROM v1;
+a
+1
+2
+# Make sure hints are not present inside the view definition:
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select `t1`.`a` AS `a` from `t1`	utf8mb4	utf8mb4_uca1400_ai_ci
+EXPLAIN EXTENDED SELECT * FROM v1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	index	NULL	idx_a	5	NULL	2	100.00	Using index
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1`
+CREATE OR REPLACE VIEW v1 AS SELECT /*+ NO_MRR(t1 idx_a) BKA(t1)*/ a FROM t1;
+Warnings:
+Warning	4206	Optimizer hints are not supported inside view definitions
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select `t1`.`a` AS `a` from `t1`	utf8mb4	utf8mb4_uca1400_ai_ci
+ALTER VIEW v1 AS SELECT /*+ QB_NAME(q1)*/ a FROM t1;
+Warnings:
+Warning	4206	Optimizer hints are not supported inside view definitions
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select `t1`.`a` AS `a` from `t1`	utf8mb4	utf8mb4_uca1400_ai_ci
+SELECT * FROM v1;
+a
+1
+2
+# Wrong place for the hint, must be simply ignored:
+CREATE OR REPLACE VIEW v1 AS SELECT a /*+ NO_ICP(t1 idx_a)*/ FROM t1;
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select `t1`.`a` AS `a` from `t1`	utf8mb4	utf8mb4_uca1400_ai_ci
+# Incorrect hint does not prevent view creation, only a warning generated:
+CREATE VIEW v2 AS SELECT /*+ BAD HINT*/ a+10 FROM t1;
+Warnings:
+Warning	1064	Optimizer hint syntax error near 'BAD HINT*/ a+10 FROM t1' at line 1
+SELECT * FROM v2;
+a+10
+11
+12
+EXPLAIN EXTENDED SELECT * FROM v2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	index	NULL	idx_a	5	NULL	2	100.00	Using index
+Warnings:
+Note	1003	select `test`.`t1`.`a` + 10 AS `a+10` from `test`.`t1`
+SHOW CREATE VIEW v2;
+View	Create View	character_set_client	collation_connection
+v2	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v2` AS select `t1`.`a` + 10 AS `a+10` from `t1`	utf8mb4	utf8mb4_uca1400_ai_ci
+DROP VIEW v1, v2;
+DROP TABLE t1;
+#
+# Tests of parser for optimizer hints
+#
 CREATE TABLE t1 (i INT, j INT);
 CREATE INDEX i1 ON t1(i);
 CREATE INDEX i2 ON t1(j);
@@ -1450,6 +1512,10 @@ SELECT 1 FROM /*+ #1 */ t1 WHERE /*+ #2 */ 1 /*+ #3 */;
 1
 1
 1
+SELECT 1 FROM /*+ QB_NAME(q1) */ t1 /*+ NO_ICP() */WHERE /*+ NO_MRR(t1) */ 1 /*+ #3 */;
+1
+1
+1
 # Warnings expected:
 SELECT /*+ NO_ICP() */ 1
 FROM /*+ regular commentary, not a hint! */ t1;

mysql-test/main/opt_hints.test

 --enable_prepare_warnings
-
+--disable_view_protocol # Since optimizer hints are not supported inside views
 SET NAMES utf8mb4;
 
 --echo # Testing that index names in hints are accent sensitive case insensitive
@@ -7,8 +7,13 @@ CREATE TABLE t1 (a INT, ä INT, INDEX idx_a(a), INDEX idx_ä(ä));
 INSERT INTO t1 VALUES (1,1),(2,2);
 SELECT /*+ NO_MRR(t1 idx_a) */ a FROM t1;
 SELECT /*+ NO_MRR(t1 idx_A) */ a FROM t1;
+
+# Warnings "Unresolved table/index name..." are generated during both prepare
+# and execution stages. So disable PS protocol to avoid duplication
+--disable_ps_protocol
 SELECT /*+ NO_MRR(t1 idx_å) */ a FROM t1;
 SELECT /*+ NO_MRR(t1 idx_a, idx_å, idx_A) */ a FROM t1;
+--enable_ps_protocol
 DROP TABLE t1;
 
 --echo # Testing that query block names are accent sensitive case insensitive
@@ -129,9 +134,13 @@ EXPLAIN EXTENDED SELECT /*+ NO_ICP(t5@блок1 x_idx) */ * FROM
 
 
 --echo # Expected warning for z_idx key, unresolved name.
+# Warnings "Unresolved table/index name..." are generated during both prepare
+# and execution stages. So disable PS protocol to avoid duplication
+--disable_ps_protocol
 EXPLAIN EXTENDED SELECT * FROM
   (SELECT /*+ NO_ICP(t5 y_idx, x_idx, z_idx) */ t4.x, t5.y FROM t4, t4 t5
    WHERE t4.y = 8 AND t5.x BETWEEN 7 AND t4.y+0) AS TD;
+--enable_ps_protocol
 
 --echo # ICP should still be used
 EXPLAIN EXTENDED SELECT * FROM
@@ -300,10 +309,14 @@ EXPLAIN EXTENDED SELECT /*+ BKA(tbl12, tbl13) */ * FROM t12 tbl12, t13 tbl13
 WHERE tbl12.a=tbl13.a AND (tbl13.b+1 <= tbl13.b+1);
 
 --echo # Print warnings for nonexistent names
+# Warnings "Unresolved table/index name..." are generated during both prepare
+# and execution stages. So disable PS protocol to avoid duplication
+--disable_ps_protocol
 EXPLAIN EXTENDED
 SELECT /*+ BKA(t2) NO_BNL(t1) BKA(t3) NO_RANGE_OPTIMIZATION(t3 idx1) NO_RANGE_OPTIMIZATION(t3) */
 t2.f1, t2.f2, t2.f3 FROM t1,t2 WHERE t1.f1=t2.f1 AND
 t2.f2 BETWEEN t1.f1 AND t1.f2 AND t2.f2 + 1 >= t1.f1 + 1;
+--enable_ps_protocol
 
 --echo # Check illegal syntax
 EXPLAIN EXTENDED SELECT /*+ BKA(qb1 t3@qb1) */ f2 FROM
@@ -319,8 +332,12 @@ EXPLAIN EXTENDED SELECT /*+ BKA(@qb1 t13) */ * FROM (SELECT /*+ QB_NAME(QB1) */
 WHERE t12.a=t13.a AND (t13.b+1 <= t13.b+1)) AS s1;
 
 --echo # Check that original table name is not recognized if alias is used.
+# Warnings "Unresolved table/index name..." are generated during both prepare
+# and execution stages. So disable PS protocol to avoid duplication
+--disable_ps_protocol
 EXPLAIN EXTENDED SELECT /*+ BKA(tbl2) */ * FROM t12 tbl12, t13 tbl13 
 WHERE tbl12.a=tbl13.a AND (tbl13.b+1 <= tbl13.b+1);
+--enable_ps_protocol
 
 --disable_ps2_protocol
 --echo # Check that PS and conventional statements give the same result.
@@ -500,8 +517,41 @@ SELECT /*+ QB_NAME(q1) NO_ICP(@q1 t1 PRIMARY) NO_ICP(@q1 t1 PRIMARY) */ * FROM t
 
 DROP TABLE t1;
 
---echo # WL#8016 Parser for optimizer hints
+--echo #
+--echo # Hints inside views are not supported
+--echo #
+CREATE TABLE t1 (a INT, INDEX idx_a(a));
+INSERT INTO t1 VALUES (1),(2);
+
+CREATE VIEW v1 AS SELECT /*+ NO_MRR(t1 idx_a) */ a FROM t1;
+SELECT * FROM v1;
+--echo # Make sure hints are not present inside the view definition:
+SHOW CREATE VIEW v1;
+EXPLAIN EXTENDED SELECT * FROM v1;
+
+CREATE OR REPLACE VIEW v1 AS SELECT /*+ NO_MRR(t1 idx_a) BKA(t1)*/ a FROM t1;
+SHOW CREATE VIEW v1;
+
+ALTER VIEW v1 AS SELECT /*+ QB_NAME(q1)*/ a FROM t1;
+SHOW CREATE VIEW v1;
+SELECT * FROM v1;
+
+--echo # Wrong place for the hint, must be simply ignored:
+CREATE OR REPLACE VIEW v1 AS SELECT a /*+ NO_ICP(t1 idx_a)*/ FROM t1;
+SHOW CREATE VIEW v1;
 
+--echo # Incorrect hint does not prevent view creation, only a warning generated:
+CREATE VIEW v2 AS SELECT /*+ BAD HINT*/ a+10 FROM t1;
+SELECT * FROM v2;
+EXPLAIN EXTENDED SELECT * FROM v2;
+SHOW CREATE VIEW v2;
+
+DROP VIEW v1, v2;
+DROP TABLE t1;
+
+--echo #
+--echo # Tests of parser for optimizer hints
+--echo #
 
 CREATE TABLE t1 (i INT, j INT);
 CREATE INDEX i1 ON t1(i);
@@ -552,8 +602,12 @@ DELETE  /*+ NO_ICP() */ FROM t1 WHERE 1;
 
 SELECT /*+ BKA(a b) */   1 FROM t1 a, t1 b;
 
+# Warnings "Unresolved table/index name..." are generated during both prepare
+# and execution stages. So disable PS protocol to avoid duplication
+--disable_ps_protocol
 SELECT /*+ NO_ICP(i1) */ 1 FROM t1;
 SELECT /*+ NO_ICP(i1 i2) */ 1 FROM t1;
+--enable_ps_protocol
 SELECT /*+ NO_ICP(@qb ident) */ 1 FROM t1;
 
 --echo
@@ -578,6 +632,10 @@ EXPLAIN EXTENDED DELETE /*+ test */ FROM t1 WHERE i = 10;
 --echo
 
 CREATE INDEX 3rd_index ON t1(i, j);
+
+# Warnings "Unresolved table/index name..." are generated during both prepare
+# and execution stages. So disable PS protocol to avoid duplication
+--disable_ps_protocol
 SELECT /*+ NO_ICP(3rd_index) */ 1 FROM t1;
 
 CREATE INDEX $index ON t1(j, i);
@@ -605,6 +663,7 @@ SELECT /*+ BKA(" quoted name test") */ 1 FROM t1;
 
 DROP TABLE ` quoted name test`;
 DROP TABLE `test1``test2```;
+--enable_ps_protocol
 
 --echo # Valid hints, no warning:
 EXPLAIN EXTENDED SELECT /*+ QB_NAME(`*`) */ 1;
@@ -622,6 +681,10 @@ EXPLAIN EXTENDED SELECT /*+ QB_NAME(`\BF``\BF`) */ 1;
 CREATE TABLE tableТ (i INT);
 
 --echo # invalid hints, should warn:
+
+# Warnings "Unresolved table/index name..." are generated during both prepare
+# and execution stages. So disable PS protocol to avoid duplication
+--disable_ps_protocol
 SELECT /*+ BKA(tableТ) */ 1 FROM t1;
 SELECT /*+ BKA(test@tableТ) */ 1 FROM t1;
 DROP TABLE tableТ;
@@ -635,6 +698,7 @@ SELECT /*+ BKA(test@таблица) */ 1 FROM t1;
 SELECT /*+ NO_ICP(`\D1`) */ 1 FROM t1;
 
 DROP TABLE таблица;
+--enable_ps_protocol
 
 --echo
 --echo # derived tables and other subqueries:
@@ -649,7 +713,9 @@ SELECT 1 FROM DUAL WHERE 1 IN (SELECT /*+ DEBUG_HINT3 */ 1);
 --echo
 SELECT /*+ 10 */ 1;
 SELECT /*+ NO_ICP() */ 1;
+--disable_ps_protocol # to avoid warnings duplication, see details above
 SELECT /*+ NO_ICP(10) */ 1;
+--enable_ps_protocol
 SELECT /*+ NO_ICP( */ 1;
 SELECT /*+ NO_ICP) */ 1;
 SELECT /*+ NO_ICP(t1 */ 1;
@@ -664,6 +730,7 @@ INSERT INTO t1 VALUES (1, 1), (2, 2);
 
 SELECT 1 FROM /*+ regular commentary, not a hint! */ t1;
 SELECT 1 FROM /*+ #1 */ t1 WHERE /*+ #2 */ 1 /*+ #3 */;
+SELECT 1 FROM /*+ QB_NAME(q1) */ t1 /*+ NO_ICP() */WHERE /*+ NO_MRR(t1) */ 1 /*+ #3 */;
 
 --echo # Warnings expected:
 SELECT /*+ NO_ICP() */ 1

sql/opt_hints.cc

@@ -674,6 +674,15 @@ bool Optimizer_hint_parser::Qb_name_hint::resolve(Parse_context *pc) const
 
 bool Optimizer_hint_parser::Hint_list::resolve(Parse_context *pc)
 {
+  if (pc->thd->lex->create_view)
+  {
+    // we're creating or modifying a view, hints are not allowed here
+    push_warning_printf(pc->thd, Sql_condition::WARN_LEVEL_WARN,
+                        ER_HINTS_INSIDE_VIEWS_NOT_SUPPORTED,
+                        ER_THD(pc->thd, ER_HINTS_INSIDE_VIEWS_NOT_SUPPORTED));
+    return false;
+  }
+
   if (!get_qb_hints(pc))
     return true;
 

sql/share/errmsg-utf8.txt

@@ -12290,3 +12290,5 @@ ER_UNRESOLVED_TABLE_HINT_NAME
         eng "Unresolved table name %s for %s hint"
 ER_UNRESOLVED_INDEX_HINT_NAME
         eng "Unresolved index name %s for %s hint"
+ER_HINTS_INSIDE_VIEWS_NOT_SUPPORTED
+        eng "Optimizer hints are not supported inside view definitions"