MDEV-36106 New-style hints: [NO_]DERIVED_CONDITION_PUSHDOWN, [NO_]MERGE

Implements and tests the optimizer hints DERIVED_CONDITION_PUSHDOWN
and NO_DERIVED_CONDITION_PUSHDOWN, table-level hints to enable and
disable, respectively, the condition pushdown for derived tables
which is typically controlled by the condition_pushdown_for_derived
optimizer switch.

Implements and tests the optimizer hints MERGE and NO_MERGE, table-level
hints to enable and disable, respectively, the derived_merge optimization
which is typically controlled by the derived_merge optimizer switch.

Sometimes hints need to be fixed before TABLE instances are available, but
after TABLE_LIST instances have been created (as in the cases of MERGE and
NO_MERGE).  This commit introduces a new function called
fix_hints_for_derived_table to allow early hint fixing for derived tables,
using only a TABLE_LIST instance (so long as such hints are not index-level).

mysql-test/main/opt_hints_derived_condition_pushdown.test

@@ -0,0 +1,417 @@
+--source include/have_sequence.inc
+--disable_view_protocol
+create table t1 (a int, b int, c int);
+create table t2 (a int, b int, c int, d decimal);
+insert into t1 values
+  (1,21,345), (1,33,7), (8,33,114), (1,21,500), (1,19,107), (5,14,787),
+  (8,33,123), (9,10,211), (5,16,207), (1,33,988), (5,27,132), (1,21,104),
+  (6,20,309), (6,20,315), (1,21,101), (8,33,404), (9,10,800), (1,21,123),
+  (7,11,708), (6,20,214);
+create index t1_a on t1 (a);
+insert into t2 values
+  (2,3,207,207.0000), (1,21,909,12.0000), (7,13,312,406.0000),
+  (8,64,248,107.0000), (6,20,315,279.3333), (1,19,203,107.0000),
+  (8,80,800,314.0000), (3,12,231,190.0000), (6,23,303,909.0000);
+create view v1 as select a, b, max(c) as max_c, avg(c) as avg_c from t1
+  group by a,b having max_c < 707;
+create table t3 select 2*seq as a, 2*seq+1 as b from seq_0_to_1000;
+CREATE TABLE t4 (a INT, b INT);
+INSERT INTO t4 VALUES (1,2),(2,3),(3,4);
+create table t5 select seq as i, 10*seq as j from seq_1_to_10;
+create view v2 as select * from t5;
+create table t6 (a int primary key);
+insert into t6 select * from seq_1_to_50;
+create view v6 as select a from t6 where a mod 2 = 1;
+
+set @save_optimizer_switch=@@optimizer_switch;
+
+set session optimizer_switch='condition_pushdown_for_derived=on';
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ NO_DERIVED_CONDITION_PUSHDOWN(v1) */ * from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a));
+select /*+ NO_DERIVED_CONDITION_PUSHDOWN(v1) */ * from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a));
+select * from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a));
+
+--source include/explain-no-costs.inc
+explain format=json with cte as (
+  select /*+ QB_NAME(qb1) */ max_c, avg_c from v1,t2 where
+    ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a)))
+select /*+ NO_DERIVED_CONDITION_PUSHDOWN(v1@qb1) */ * from cte;
+with cte as (
+  select /*+ QB_NAME(qb1) */ max_c, avg_c from v1,t2 where
+    ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a)))
+select /*+ NO_DERIVED_CONDITION_PUSHDOWN(v1@qb1) */ * from cte;
+with cte as (
+  select /*+ QB_NAME(qb1) */ max_c, avg_c from v1,t2 where
+    ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a)))
+select * from cte;
+
+--source include/explain-no-costs.inc
+explain format=json with recursive cte as (
+  select max_c, avg_c from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+  ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a))
+  union
+  select * from cte where max_c < 100
+) select /*+ NO_DERIVED_CONDITION_PUSHDOWN(cte) */ * from cte;
+with recursive cte as (
+  select max_c, avg_c from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+  ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a))
+  union
+  select * from cte where max_c < 100
+) select /*+ NO_DERIVED_CONDITION_PUSHDOWN(cte) */ * from cte;
+with recursive cte as (
+  select max_c, avg_c from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+  ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a))
+  union
+  select * from cte where max_c < 100
+) select * from cte;
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ NO_DERIVED_CONDITION_PUSHDOWN(dt)*/ * from
+  (select t3.b as a from t3 group by t3.a) dt where (dt.a=3 or dt.a=5);
+select /*+ NO_DERIVED_CONDITION_PUSHDOWN(dt)*/ * from
+  (select t3.b as a from t3 group by t3.a) dt where (dt.a=3 or dt.a=5);
+select * from
+  (select t3.b as a from t3 group by t3.a) dt where (dt.a=3 or dt.a=5);
+
+--echo "This explain and query shows the result when no hints are specified, for comparison to hint cases in the next three explain and select pairs"
+--source include/explain-no-costs.inc
+explain format=json select * from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+select count(*) from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ NO_DERIVED_CONDITION_PUSHDOWN(dt)*/ * from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+select /*+ NO_DERIVED_CONDITION_PUSHDOWN(dt)*/ count(*) from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ NO_DERIVED_CONDITION_PUSHDOWN(du)*/ * from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+select /*+ NO_DERIVED_CONDITION_PUSHDOWN(du)*/ count(*) from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ NO_DERIVED_CONDITION_PUSHDOWN(dt,du)*/ * from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+select /*+ NO_DERIVED_CONDITION_PUSHDOWN(dt,du)*/ count(*) from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+
+--source include/explain-no-costs.inc
+explain format=json SELECT /*+ NO_DERIVED_CONDITION_PUSHDOWN(dt) */ * FROM (
+  SELECT t4.b AS a
+  FROM t4
+  GROUP BY t4.a
+) dt WHERE (dt.a=2);
+SELECT /*+ NO_DERIVED_CONDITION_PUSHDOWN(dt) */ * FROM (
+  SELECT t4.b AS a
+  FROM t4
+  GROUP BY t4.a
+) dt WHERE (dt.a=2);
+SELECT * FROM (
+  SELECT t4.b AS a
+  FROM t4
+  GROUP BY t4.a
+) dt WHERE (dt.a=2);
+
+--source include/explain-no-costs.inc
+explain format=json SELECT /*+ NO_DERIVED_CONDITION_PUSHDOWN(dt) */ * FROM (
+  SELECT qb.b AS a
+  FROM (
+    select 1*t4.b as b, 1*t4.a as a from t4
+  ) qb
+  GROUP BY qb.a
+) dt WHERE (dt.a=2);
+SELECT /*+ NO_DERIVED_CONDITION_PUSHDOWN(dt) */ * FROM (
+  SELECT qb.b AS a
+  FROM (
+    select 1*t4.b as b, 1*t4.a as a from t4
+  ) qb
+  GROUP BY qb.a
+) dt WHERE (dt.a=2);
+SELECT * FROM (
+  SELECT qb.b AS a
+  FROM (
+    select 1*t4.b as b, 1*t4.a as a from t4
+  ) qb
+  GROUP BY qb.a
+) dt WHERE (dt.a=2);
+
+--source include/explain-no-costs.inc
+explain format=json
+select /*+ NO_DERIVED_CONDITION_PUSHDOWN(@qb1 dv6) */ * from
+  (select /*+ QB_NAME(qb4) */ * from
+    (select /*+ QB_NAME(qb3) */ * from
+      (select /*+ QB_NAME(qb2) */ * from
+        (select /*+ QB_NAME(qb1) */ avg_a from
+          (select avg(a) as avg_a from v6) dv6
+        ) dv6) dv6) dv6) dv6 where avg_a <> 0;
+
+--source include/explain-no-costs.inc
+explain format=json
+select /*+ NO_DERIVED_CONDITION_PUSHDOWN(@qb2 dv6) */ * from
+  (select /*+ QB_NAME(qb4) */ * from
+    (select /*+ QB_NAME(qb3) */ * from
+      (select /*+ QB_NAME(qb2) */ * from
+        (select /*+ QB_NAME(qb1) */ avg_a from
+          (select avg(a) as avg_a from v6) dv6
+        ) dv6) dv6) dv6) dv6 where avg_a <> 0;
+
+--source include/explain-no-costs.inc
+explain format=json
+select /*+ NO_DERIVED_CONDITION_PUSHDOWN(@qb3 dv6) */ * from
+  (select /*+ QB_NAME(qb4) */ * from
+    (select /*+ QB_NAME(qb3) */ * from
+      (select /*+ QB_NAME(qb2) */ * from
+        (select /*+ QB_NAME(qb1) */ avg_a from
+          (select avg(a) as avg_a from v6) dv6
+        ) dv6) dv6) dv6) dv6 where avg_a <> 0;
+
+--source include/explain-no-costs.inc
+explain format=json
+select /*+ NO_DERIVED_CONDITION_PUSHDOWN(@qb4 dv6) */ * from
+  (select /*+ QB_NAME(qb4) */ * from
+    (select /*+ QB_NAME(qb3) */ * from
+      (select /*+ QB_NAME(qb2) */ * from
+        (select /*+ QB_NAME(qb1) */ avg_a from
+          (select avg(a) as avg_a from v6) dv6
+        ) dv6) dv6) dv6) dv6 where avg_a <> 0;
+
+set session optimizer_switch='condition_pushdown_for_derived=off';
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ DERIVED_CONDITION_PUSHDOWN(v1) */ * from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a));
+select /*+ DERIVED_CONDITION_PUSHDOWN(v1) */ * from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a));
+select * from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a));
+
+--source include/explain-no-costs.inc
+explain format=json with cte as (
+  select /*+ QB_NAME(qb1) */ max_c, avg_c from v1,t2 where
+    ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a)))
+select /*+ DERIVED_CONDITION_PUSHDOWN(v1@qb1) */ * from cte;
+with cte as (
+  select /*+ QB_NAME(qb1) */ max_c, avg_c from v1,t2 where
+    ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a)))
+select /*+ DERIVED_CONDITION_PUSHDOWN(v1@qb1) */ * from cte;
+with cte as (
+  select /*+ QB_NAME(qb1) */ max_c, avg_c from v1,t2 where
+    ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+    ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a)))
+select * from cte;
+
+--source include/explain-no-costs.inc
+explain format=json with recursive cte as (
+  select /*+ QB_NAME(qb1) */ max_c, avg_c from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+  ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a))
+  union
+  select /*+ QB_NAME(qb2) */ * from cte where max_c < 100
+) select /*+ DERIVED_CONDITION_PUSHDOWN(v1@qb1) DERIVED_CONDITION_PUSHDOWN(cte) */ * from cte;
+with recursive cte as (
+  select /*+ QB_NAME(qb1) */ max_c, avg_c from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+  ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a))
+  union
+  select /*+ QB_NAME(qb2) */ * from cte where max_c < 100
+) select /*+ DERIVED_CONDITION_PUSHDOWN(v1@qb1) DERIVED_CONDITION_PUSHDOWN(cte) */ * from cte;
+with recursive cte as (
+  select max_c, avg_c from v1,t2 where
+  ((v1.max_c>300) and (v1.avg_c>t2.d) and (v1.b=t2.b)) or
+  ((v1.max_c<135) and (v1.max_c<t2.c) and (v1.a=t2.a))
+  union
+  select * from cte where max_c < 100
+) select * from cte;
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ DERIVED_CONDITION_PUSHDOWN(dt)*/ * from
+  (select t3.b as a from t3 group by t3.a) dt where (dt.a=3 or dt.a=5);
+select /*+ DERIVED_CONDITION_PUSHDOWN(dt)*/ * from
+  (select t3.b as a from t3 group by t3.a) dt where (dt.a=3 or dt.a=5);
+select * from
+  (select t3.b as a from t3 group by t3.a) dt where (dt.a=3 or dt.a=5);
+
+--source include/explain-no-costs.inc
+explain format=json SELECT /*+ DERIVED_CONDITION_PUSHDOWN(dt) */ * FROM (
+  SELECT t4.b AS a
+  FROM t4
+  GROUP BY t4.a
+) dt WHERE (dt.a=2);
+SELECT /*+ DERIVED_CONDITION_PUSHDOWN(dt) */ * FROM (
+  SELECT t4.b AS a
+  FROM t4
+  GROUP BY t4.a
+) dt WHERE (dt.a=2);
+SELECT * FROM (
+  SELECT t4.b AS a
+  FROM t4
+  GROUP BY t4.a
+) dt WHERE (dt.a=2);
+
+--source include/explain-no-costs.inc
+explain format=json SELECT /*+ DERIVED_CONDITION_PUSHDOWN(dt) */ * FROM (
+  SELECT qb.b AS a
+  FROM (
+    select 1*t4.b as b, 1*t4.a as a from t4
+  ) qb
+  GROUP BY qb.a
+) dt WHERE (dt.a=2);
+SELECT /*+ DERIVED_CONDITION_PUSHDOWN(dt) */ * FROM (
+  SELECT qb.b AS a
+  FROM (
+    select 1*t4.b as b, 1*t4.a as a from t4
+  ) qb
+  GROUP BY qb.a
+) dt WHERE (dt.a=2);
+SELECT * FROM (
+  SELECT qb.b AS a
+  FROM (
+    select 1*t4.b as b, 1*t4.a as a from t4
+  ) qb
+  GROUP BY qb.a
+) dt WHERE (dt.a=2);
+
+--echo "This explain and query shows the result when no hints are specified, for comparison to hint cases in the next three explain and select pairs"
+--source include/explain-no-costs.inc
+explain format=json select * from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+select count(*) from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ DERIVED_CONDITION_PUSHDOWN(dt)*/ * from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+select /*+ DERIVED_CONDITION_PUSHDOWN(dt)*/ count(*) from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ DERIVED_CONDITION_PUSHDOWN(du)*/ * from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+select /*+ DERIVED_CONDITION_PUSHDOWN(du)*/ count(*) from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ DERIVED_CONDITION_PUSHDOWN(dt,du)*/ * from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+select /*+ DERIVED_CONDITION_PUSHDOWN(dt,du)*/ count(*) from (
+  select t3.b as a from t3 group by t3.a
+) dt join (
+  select t3.a as a, t3.b as b from t3 where t3.a % 2 = 0 group by t3.b
+) du where (dt.a=3 or dt.a=5) and (du.a % 10 <> 0 or du.a % 5 <> 0);
+
+--source include/explain-no-costs.inc
+explain format=json
+select /*+ DERIVED_CONDITION_PUSHDOWN(@qb1 dv6) */ * from
+  (select /*+ QB_NAME(qb4) */ * from
+    (select /*+ QB_NAME(qb3) */ * from
+      (select /*+ QB_NAME(qb2) */ * from
+        (select /*+ QB_NAME(qb1) */ avg_a from
+          (select avg(a) as avg_a from v6) dv6
+        ) dv6) dv6) dv6) dv6 where avg_a <> 0;
+
+--source include/explain-no-costs.inc
+explain format=json
+select /*+ DERIVED_CONDITION_PUSHDOWN(@qb2 dv6) */ * from
+  (select /*+ QB_NAME(qb4) */ * from
+    (select /*+ QB_NAME(qb3) */ * from
+      (select /*+ QB_NAME(qb2) */ * from
+        (select /*+ QB_NAME(qb1) */ avg_a from
+          (select avg(a) as avg_a from v6) dv6
+        ) dv6) dv6) dv6) dv6 where avg_a <> 0;
+
+--source include/explain-no-costs.inc
+explain format=json
+select /*+ DERIVED_CONDITION_PUSHDOWN(@qb3 dv6) */ * from
+  (select /*+ QB_NAME(qb4) */ * from
+    (select /*+ QB_NAME(qb3) */ * from
+      (select /*+ QB_NAME(qb2) */ * from
+        (select /*+ QB_NAME(qb1) */ avg_a from
+          (select avg(a) as avg_a from v6) dv6
+        ) dv6) dv6) dv6) dv6 where avg_a <> 0;
+
+--source include/explain-no-costs.inc
+explain format=json
+select /*+ DERIVED_CONDITION_PUSHDOWN(@qb4 dv6) */ * from
+  (select /*+ QB_NAME(qb4) */ * from
+    (select /*+ QB_NAME(qb3) */ * from
+      (select /*+ QB_NAME(qb2) */ * from
+        (select /*+ QB_NAME(qb1) */ avg_a from
+          (select avg(a) as avg_a from v6) dv6
+        ) dv6) dv6) dv6) dv6 where avg_a <> 0;
+
+set optimizer_switch=@save_optimizer_switch;
+
+create table t7(a int);
+insert into t7 values (1),(2),(3);
+explain extended select /*+ NO_MERGE(t) NO_ICP(t key1) */ * from (select * from t7) t;
+explain extended select /*+ NO_MERGE(t) NO_ICP(t) */ * from (select * from t7) t;
+
+drop view v1, v2, v6;
+drop table t1, t2, t3, t4, t5, t6, t7;
+--enable_view_protocol

mysql-test/main/opt_hints_merge.result

@@ -0,0 +1,469 @@
+create table t1 select seq as i, 10*seq as j from seq_1_to_10;
+create view v1 as select * from t1 where i % 2 = 0;
+set @save_optimizer_switch=@@optimizer_switch;
+set session optimizer_switch='derived_merge=on';
+explain format=json SELECT a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "cost": "COST_REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "loops": 1,
+          "rows": 10,
+          "cost": "COST_REPLACED",
+          "filtered": 100,
+          "attached_condition": "t1.i < 3 and t1.j > 8"
+        }
+      }
+    ]
+  }
+}
+SELECT a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+a	b
+1	10
+2	20
+explain format=json SELECT /*+ NO_MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "cost": "COST_REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "<derived2>",
+          "access_type": "ALL",
+          "loops": 1,
+          "rows": 10,
+          "cost": "COST_REPLACED",
+          "filtered": 100,
+          "attached_condition": "dt.a < 3 and dt.b > 8",
+          "materialized": {
+            "query_block": {
+              "select_id": 2,
+              "cost": "COST_REPLACED",
+              "nested_loop": [
+                {
+                  "table": {
+                    "table_name": "t1",
+                    "access_type": "ALL",
+                    "loops": 1,
+                    "rows": 10,
+                    "cost": "COST_REPLACED",
+                    "filtered": 100,
+                    "attached_condition": "t1.i < 3 and t1.j > 8"
+                  }
+                }
+              ]
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+SELECT /*+ NO_MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+a	b
+1	10
+2	20
+explain format=json select * from (select i, j from v1) dt where dt.j % 5 = 0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "cost": "COST_REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "loops": 1,
+          "rows": 10,
+          "cost": "COST_REPLACED",
+          "filtered": 100,
+          "attached_condition": "t1.j MOD 5 = 0 and t1.i MOD 2 = 0"
+        }
+      }
+    ]
+  }
+}
+select * from (select i, j from v1) dt where dt.j % 5 = 0;
+i	j
+2	20
+4	40
+6	60
+8	80
+10	100
+explain format=json select /*+ NO_MERGE(dt) */ * from (select /*+ NO_MERGE(v1) */ i, j from v1) dt where dt.j % 5 = 0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "cost": "COST_REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "<derived2>",
+          "access_type": "ALL",
+          "loops": 1,
+          "rows": 10,
+          "cost": "COST_REPLACED",
+          "filtered": 100,
+          "attached_condition": "dt.j MOD 5 = 0",
+          "materialized": {
+            "query_block": {
+              "select_id": 2,
+              "cost": "COST_REPLACED",
+              "nested_loop": [
+                {
+                  "table": {
+                    "table_name": "t1",
+                    "access_type": "ALL",
+                    "loops": 1,
+                    "rows": 10,
+                    "cost": "COST_REPLACED",
+                    "filtered": 100,
+                    "attached_condition": "t1.i MOD 2 = 0 and t1.j MOD 5 = 0"
+                  }
+                }
+              ]
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+select /*+ NO_MERGE(dt) */ * from (select /*+ NO_MERGE(v1) */ i, j from v1) dt where dt.j % 5 = 0;
+i	j
+2	20
+4	40
+6	60
+8	80
+10	100
+explain format=json select /*+ NO_MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "cost": "COST_REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "<derived2>",
+          "access_type": "ALL",
+          "loops": 1,
+          "rows": 10,
+          "cost": "COST_REPLACED",
+          "filtered": 100,
+          "attached_condition": "dt.j MOD 5 = 0",
+          "materialized": {
+            "query_block": {
+              "select_id": 2,
+              "cost": "COST_REPLACED",
+              "nested_loop": [
+                {
+                  "table": {
+                    "table_name": "t1",
+                    "access_type": "ALL",
+                    "loops": 1,
+                    "rows": 10,
+                    "cost": "COST_REPLACED",
+                    "filtered": 100,
+                    "attached_condition": "t1.i MOD 2 = 0 and t1.j MOD 5 = 0"
+                  }
+                }
+              ]
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+select /*+ NO_MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+i	j
+2	20
+4	40
+6	60
+8	80
+10	100
+explain extended SELECT /*+ NO_MERGE(dt2) NO_MERGE(dt)*/ * FROM
+(SELECT i as a, j as b FROM t1) AS dt, (SELECT i as a, j as b FROM t1) AS dt2
+WHERE dt.a = dt2.a and dt.b = dt2.b AND dt.a < 3 AND dt.b > 8;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
+1	PRIMARY	<derived3>	ref	key0	key0	16	dt.a,dt.b	1	100.00	
+3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
+Warnings:
+Note	1003	/* select#1 */ select /*+ NO_MERGE(`dt2`@`select#1`) NO_MERGE(`dt`@`select#1`) */ `dt`.`a` AS `a`,`dt`.`b` AS `b`,`dt2`.`a` AS `a`,`dt2`.`b` AS `b` from (/* select#2 */ select `test`.`t1`.`i` AS `a`,`test`.`t1`.`j` AS `b` from `test`.`t1` where `test`.`t1`.`i` < 3 and `test`.`t1`.`j` > 8) `dt` join (/* select#3 */ select `test`.`t1`.`i` AS `a`,`test`.`t1`.`j` AS `b` from `test`.`t1` where `test`.`t1`.`i` < 3 and `test`.`t1`.`j` > 8) `dt2` where `dt2`.`a` = `dt`.`a` and `dt2`.`b` = `dt`.`b` and `dt`.`a` < 3 and `dt`.`b` > 8
+set session optimizer_switch='derived_merge=off';
+explain format=json SELECT a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "cost": "COST_REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "<derived2>",
+          "access_type": "ALL",
+          "loops": 1,
+          "rows": 10,
+          "cost": "COST_REPLACED",
+          "filtered": 100,
+          "attached_condition": "dt.a < 3 and dt.b > 8",
+          "materialized": {
+            "query_block": {
+              "select_id": 2,
+              "cost": "COST_REPLACED",
+              "nested_loop": [
+                {
+                  "table": {
+                    "table_name": "t1",
+                    "access_type": "ALL",
+                    "loops": 1,
+                    "rows": 10,
+                    "cost": "COST_REPLACED",
+                    "filtered": 100,
+                    "attached_condition": "t1.i < 3 and t1.j > 8"
+                  }
+                }
+              ]
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+SELECT a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+a	b
+1	10
+2	20
+explain format=json select /*+ MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "cost": "COST_REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "loops": 1,
+          "rows": 10,
+          "cost": "COST_REPLACED",
+          "filtered": 100,
+          "attached_condition": "t1.j MOD 5 = 0 and t1.i MOD 2 = 0"
+        }
+      }
+    ]
+  }
+}
+select /*+ MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+i	j
+2	20
+4	40
+6	60
+8	80
+10	100
+explain format=json select * from (select i, j from v1) dt where dt.j % 5 = 0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "cost": "COST_REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "<derived2>",
+          "access_type": "ALL",
+          "loops": 1,
+          "rows": 10,
+          "cost": "COST_REPLACED",
+          "filtered": 100,
+          "attached_condition": "dt.j MOD 5 = 0",
+          "materialized": {
+            "query_block": {
+              "select_id": 2,
+              "cost": "COST_REPLACED",
+              "nested_loop": [
+                {
+                  "table": {
+                    "table_name": "t1",
+                    "access_type": "ALL",
+                    "loops": 1,
+                    "rows": 10,
+                    "cost": "COST_REPLACED",
+                    "filtered": 100,
+                    "attached_condition": "t1.i MOD 2 = 0 and t1.j MOD 5 = 0"
+                  }
+                }
+              ]
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+select * from (select i, j from v1) dt where dt.j % 5 = 0;
+i	j
+2	20
+4	40
+6	60
+8	80
+10	100
+explain format=json select /*+ MERGE(dt) */ * from (select /*+ MERGE(v1) */ i, j from v1) dt where dt.j % 5 = 0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "cost": "COST_REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "loops": 1,
+          "rows": 10,
+          "cost": "COST_REPLACED",
+          "filtered": 100,
+          "attached_condition": "t1.j MOD 5 = 0 and t1.i MOD 2 = 0"
+        }
+      }
+    ]
+  }
+}
+select /*+ MERGE(dt) */ * from (select /*+ MERGE(v1) */ i, j from v1) dt where dt.j % 5 = 0;
+i	j
+2	20
+4	40
+6	60
+8	80
+10	100
+explain format=json select /*+ MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "cost": "COST_REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "loops": 1,
+          "rows": 10,
+          "cost": "COST_REPLACED",
+          "filtered": 100,
+          "attached_condition": "t1.j MOD 5 = 0 and t1.i MOD 2 = 0"
+        }
+      }
+    ]
+  }
+}
+select /*+ MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+i	j
+2	20
+4	40
+6	60
+8	80
+10	100
+explain extended SELECT /*+ MERGE(dt2) MERGE(dt)*/ * FROM
+(SELECT i as a, j as b FROM t1) AS dt, (SELECT i as a, j as b FROM t1) AS dt2
+WHERE dt.a = dt2.a and dt.b = dt2.b AND dt.a < 3 AND dt.b > 8;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where; Using join buffer (flat, BNL join)
+Warnings:
+Note	1003	select /*+ MERGE(`dt2`@`select#1`) MERGE(`dt`@`select#1`) */ `test`.`t1`.`i` AS `a`,`test`.`t1`.`j` AS `b`,`test`.`t1`.`i` AS `a`,`test`.`t1`.`j` AS `b` from `test`.`t1` join `test`.`t1` where `test`.`t1`.`i` = `test`.`t1`.`i` and `test`.`t1`.`j` = `test`.`t1`.`j` and `test`.`t1`.`i` < 3 and `test`.`t1`.`j` > 8
+set optimizer_switch=@save_optimizer_switch;
+explain extended select /*+ NO_MERGE(t) */ * from (select * from t1) t;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	10	100.00	
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	
+Warnings:
+Note	1003	/* select#1 */ select /*+ NO_MERGE(`t`@`select#1`) */ `t`.`i` AS `i`,`t`.`j` AS `j` from (/* select#2 */ select `test`.`t1`.`i` AS `i`,`test`.`t1`.`j` AS `j` from `test`.`t1`) `t`
+explain extended select /*+ MERGE(t) */ * from (select * from t1) t;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	
+Warnings:
+Note	1003	select /*+ MERGE(`t`@`select#1`) */ `test`.`t1`.`i` AS `i`,`test`.`t1`.`j` AS `j` from `test`.`t1`
+create table t2 select seq as i, 10*seq as j from seq_1_to_10;
+create view v2 as select * from t2;
+set session optimizer_switch='derived_merge=off';
+explain extended
+SELECT /*+ merge(wrong_name) */a, b FROM
+(SELECT /*+ merge(wrong_name) */ i as a, j as b FROM
+(select i*10 as i, j*5 as j from v2) dt_in) AS dt_out
+WHERE a < 3 AND b > 8;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
+2	DERIVED	<derived3>	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
+3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
+Warnings:
+Warning	4221	Unresolved table name `wrong_name`@`select#2` for MERGE hint
+Warning	4221	Unresolved table name `wrong_name`@`select#1` for MERGE hint
+Note	1003	/* select#1 */ select `dt_out`.`a` AS `a`,`dt_out`.`b` AS `b` from (/* select#2 */ select `dt_in`.`i` AS `a`,`dt_in`.`j` AS `b` from (/* select#3 */ select `test`.`t2`.`i` * 10 AS `i`,`test`.`t2`.`j` * 5 AS `j` from `test`.`t2` where `test`.`t2`.`i` * 10 < 3 and `test`.`t2`.`j` * 5 > 8) `dt_in` where `dt_in`.`i` < 3 and `dt_in`.`j` > 8) `dt_out` where `dt_out`.`a` < 3 and `dt_out`.`b` > 8
+SELECT /*+ MERGE(dt) MERGE(foo) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+a	b
+1	10
+2	20
+Warnings:
+Warning	4221	Unresolved table name `foo`@`select#1` for MERGE hint
+SELECT /*+ MERGE(dt) MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+a	b
+1	10
+2	20
+Warnings:
+Warning	4219	Hint MERGE(`dt`) is ignored as conflicting/duplicated
+SELECT /*+ MERGE(bar) MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+a	b
+1	10
+2	20
+Warnings:
+Warning	4221	Unresolved table name `bar`@`select#1` for MERGE hint
+SELECT /*+ MERGE(bar) MERGE(foo) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+a	b
+1	10
+2	20
+Warnings:
+Warning	4221	Unresolved table name `bar`@`select#1` for MERGE hint
+Warning	4221	Unresolved table name `foo`@`select#1` for MERGE hint
+SELECT /*+ NO_MERGE(dt) NO_MERGE(foo) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+a	b
+1	10
+2	20
+Warnings:
+Warning	4221	Unresolved table name `foo`@`select#1` for NO_MERGE hint
+SELECT /*+ NO_MERGE(dt) NO_MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+a	b
+1	10
+2	20
+Warnings:
+Warning	4219	Hint NO_MERGE(`dt`) is ignored as conflicting/duplicated
+SELECT /*+ NO_MERGE(bar) NO_MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+a	b
+1	10
+2	20
+Warnings:
+Warning	4221	Unresolved table name `bar`@`select#1` for NO_MERGE hint
+SELECT /*+ NO_MERGE(bar) NO_MERGE(foo) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+a	b
+1	10
+2	20
+Warnings:
+Warning	4221	Unresolved table name `bar`@`select#1` for NO_MERGE hint
+Warning	4221	Unresolved table name `foo`@`select#1` for NO_MERGE hint
+drop table t1, t2;
+drop view v1, v2;

mysql-test/main/opt_hints_merge.test

@@ -0,0 +1,95 @@
+--source include/have_sequence.inc
+--disable_view_protocol
+create table t1 select seq as i, 10*seq as j from seq_1_to_10;
+create view v1 as select * from t1 where i % 2 = 0;
+
+set @save_optimizer_switch=@@optimizer_switch;
+
+set session optimizer_switch='derived_merge=on';
+
+--source include/explain-no-costs.inc
+explain format=json SELECT a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+SELECT a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+
+--source include/explain-no-costs.inc
+explain format=json SELECT /*+ NO_MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+SELECT /*+ NO_MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+
+--source include/explain-no-costs.inc
+explain format=json select * from (select i, j from v1) dt where dt.j % 5 = 0;
+select * from (select i, j from v1) dt where dt.j % 5 = 0;
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ NO_MERGE(dt) */ * from (select /*+ NO_MERGE(v1) */ i, j from v1) dt where dt.j % 5 = 0;
+select /*+ NO_MERGE(dt) */ * from (select /*+ NO_MERGE(v1) */ i, j from v1) dt where dt.j % 5 = 0;
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ NO_MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+select /*+ NO_MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+
+--source include/explain-no-costs.inc
+explain extended SELECT /*+ NO_MERGE(dt2) NO_MERGE(dt)*/ * FROM
+(SELECT i as a, j as b FROM t1) AS dt, (SELECT i as a, j as b FROM t1) AS dt2
+WHERE dt.a = dt2.a and dt.b = dt2.b AND dt.a < 3 AND dt.b > 8;
+
+set session optimizer_switch='derived_merge=off';
+
+--source include/explain-no-costs.inc
+explain format=json SELECT a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+SELECT a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+select /*+ MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+
+--source include/explain-no-costs.inc
+explain format=json select * from (select i, j from v1) dt where dt.j % 5 = 0;
+select * from (select i, j from v1) dt where dt.j % 5 = 0;
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ MERGE(dt) */ * from (select /*+ MERGE(v1) */ i, j from v1) dt where dt.j % 5 = 0;
+select /*+ MERGE(dt) */ * from (select /*+ MERGE(v1) */ i, j from v1) dt where dt.j % 5 = 0;
+
+--source include/explain-no-costs.inc
+explain format=json select /*+ MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+select /*+ MERGE(dt) */ * from (select i, j from v1) dt where dt.j % 5 = 0;
+
+--source include/explain-no-costs.inc
+explain extended SELECT /*+ MERGE(dt2) MERGE(dt)*/ * FROM
+(SELECT i as a, j as b FROM t1) AS dt, (SELECT i as a, j as b FROM t1) AS dt2
+WHERE dt.a = dt2.a and dt.b = dt2.b AND dt.a < 3 AND dt.b > 8;
+
+set optimizer_switch=@save_optimizer_switch;
+
+# Test warnings
+explain extended select /*+ NO_MERGE(t) */ * from (select * from t1) t;
+explain extended select /*+ MERGE(t) */ * from (select * from t1) t;
+create table t2 select seq as i, 10*seq as j from seq_1_to_10;
+create view v2 as select * from t2;
+set session optimizer_switch='derived_merge=off';
+explain extended
+  SELECT /*+ merge(wrong_name) */a, b FROM
+     (SELECT /*+ merge(wrong_name) */ i as a, j as b FROM
+        (select i*10 as i, j*5 as j from v2) dt_in) AS dt_out
+  WHERE a < 3 AND b > 8;
+
+SELECT /*+ MERGE(dt) MERGE(foo) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+
+--disable_ps_protocol
+SELECT /*+ MERGE(dt) MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+--enable_ps_protocol
+
+SELECT /*+ MERGE(bar) MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+SELECT /*+ MERGE(bar) MERGE(foo) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+SELECT /*+ NO_MERGE(dt) NO_MERGE(foo) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+
+--disable_ps_protocol
+SELECT /*+ NO_MERGE(dt) NO_MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+--enable_ps_protocol
+
+SELECT /*+ NO_MERGE(bar) NO_MERGE(dt) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+SELECT /*+ NO_MERGE(bar) NO_MERGE(foo) */ a, b FROM (SELECT i as a, j as b FROM t1) AS dt WHERE a < 3 AND b > 8;
+
+drop table t1, t2;
+drop view v1, v2;
+--enable_view_protocol

sql/opt_hints.cc

@@ -45,6 +45,8 @@ struct st_opt_hint_info opt_hint_info[]=
   {{STRING_WITH_LEN("JOIN_SUFFIX")}, false, true, true},
   {{STRING_WITH_LEN("JOIN_ORDER")}, false, true, true},
   {{STRING_WITH_LEN("JOIN_FIXED_ORDER")}, false, true, false},
+  {{STRING_WITH_LEN("DERIVED_CONDITION_PUSHDOWN")}, false, false, false},
+  {{STRING_WITH_LEN("MERGE")}, false, false, false},
   {null_clex_str, 0, 0, 0}
 };
 
@@ -199,6 +201,7 @@ Opt_hints_qb *get_qb_hints(Parse_context *pc)
     /*
       Mark the query block as resolved as we know which SELECT_LEX it is
       attached to.
+
       Note that children (indexes, tables) are probably not resolved, yet.
     */
     qb->set_fixed();
@@ -398,10 +401,52 @@ Opt_hints_qb::Opt_hints_qb(Opt_hints *opt_hints_arg,
 }
 
 
+/**
+  fix_hints_for_derived_table allows early hint fixing for
+  derived tables by linking both *this and the Opt_hints_table
+  object to the passed TABLE_LIST instance.
+
+  @param table_list Pointer to TABLE_LIST object
+*/
+
+void Opt_hints_qb::fix_hints_for_derived_table(TABLE_LIST *table_list)
+{
+  Opt_hints_table *tab=
+    static_cast<Opt_hints_table *>(find_by_name(table_list->alias));
+
+  /*
+    If this is fixed and the corresponding Opt_hints_table doesn't exist (or it
+    exists and is fixed) then there's nothing to do, so return early.
+  */
+  if (is_fixed() && (!tab || tab->is_fixed()))
+    return;
+
+  /*
+    This instance will have been marked as fixed on the basis of its
+    attachment to a SELECT_LEX (during get_qb_hints) but that is
+    insufficient to consider it fixed for the case where a TABLE
+    instance is required but not yet available.  If the associated
+    table isn't yet fixed, then fix this hint as though it were unfixed.
+
+    We mark the Opt_hints_table as 'fixed' here and this means we
+    won't try to fix the child hints again later.  They will remain
+    unfixed and will eventually produce "Unresolved index name" error
+    in opt_hints_qb->check_unfixed().  This is acceptable because
+    no child hints apply to derived tables.
+  */
+  DBUG_ASSERT(!table_list->opt_hints_table);
+  DBUG_ASSERT(tab);
+  table_list->opt_hints_qb= this;
+  table_list->opt_hints_table= tab;
+  tab->set_fixed();
+}
+
+
 Opt_hints_table *Opt_hints_qb::fix_hints_for_table(TABLE *table,
                                                    const Lex_ident_table &alias)
 {
-  Opt_hints_table *tab= static_cast<Opt_hints_table *>(find_by_name(alias));
+  Opt_hints_table *tab=
+    static_cast<Opt_hints_table *>(find_by_name(alias));
 
   table->pos_in_table_list->opt_hints_qb= this;
 
@@ -591,11 +636,9 @@ bool hint_key_state(const THD *thd, const TABLE *table,
 }
 
 
-bool hint_table_state(const THD *thd, const TABLE *table,
+bool hint_table_state(const THD *thd, const TABLE_LIST *table_list,
-                                  opt_hints_enum type_arg,
+                      opt_hints_enum type_arg, bool fallback_value)
-                                  bool fallback_value)
 {
-  TABLE_LIST *table_list= table->pos_in_table_list;
   if (table_list->opt_hints_qb)
   {
     bool ret_val= false;
@@ -609,6 +652,15 @@ bool hint_table_state(const THD *thd, const TABLE *table,
 }
 
 
+bool hint_table_state(const THD *thd, const TABLE *table,
+                                  opt_hints_enum type_arg,
+                                  bool fallback_value)
+{
+  return hint_table_state(thd, table->pos_in_table_list, type_arg,
+                          fallback_value);
+}
+
+
 void append_table_name(THD *thd, String *str, const LEX_CSTRING &table_name,
                        const LEX_CSTRING &qb_name)
 {

sql/opt_hints.h

@@ -51,6 +51,11 @@
   each table, as a result TABLE_LIST::opt_hints_table points to the table's
   hints.
 
+  Non-index hints may be fixed before TABLE instances are available, by
+  calling fix_hints_for_derived_table and using a TABLE_LIST instance; as
+  the name implies, this is the case for derived tables (and such tables
+  are the only use case at this point).
+
   == Hint hierarchy ==
 
   Hints have this hierarchy, less specific to more specific:
@@ -178,6 +183,13 @@ protected:
     for key level.
   */
   Lex_ident_sys name;
+
+  /*
+    Hints by default are NOT_FIXED.
+    When hints are fixed, during hint resolution, they
+    transition from NOT_FIXED to FIXED.
+  */
+  enum class Fixed_state { NOT_FIXED, FIXED };
 private:
   /*
     Parent object. There is no parent for global level,
@@ -193,8 +205,8 @@ private:
   /* Array of child objects. i.e. array of the lower level objects */
   Mem_root_array<Opt_hints*, true> child_array;
 
-  /* true if hint is connected to the real object */
+  /* FIXED if hint is connected to the real object (see above) */
-  bool fixed;
+  Fixed_state fixed;
 
   /*
     Number of child hints that are fully fixed, that is, fixed and
@@ -208,7 +220,7 @@ public:
             Opt_hints *parent_arg,
             MEM_ROOT *mem_root_arg)
     : name(name_arg), parent(parent_arg), child_array(mem_root_arg),
-      fixed(false), n_fully_fixed_children(0)
+      fixed(Fixed_state::NOT_FIXED), n_fully_fixed_children(0)
   { }
 
   bool is_specified(opt_hints_enum type_arg) const
@@ -260,8 +272,8 @@ public:
   }
   void set_name(const Lex_ident_sys &name_arg) { name= name_arg; }
   Opt_hints *get_parent() const { return parent; }
-  void set_fixed() { fixed= true; }
+  void set_fixed() { fixed= Fixed_state::FIXED; }
-  bool is_fixed() const { return fixed; }
+  bool is_fixed() const { return fixed == Fixed_state::FIXED; }
   void incr_fully_fixed_children() { n_fully_fixed_children++; }
   Mem_root_array<Opt_hints*, true> *child_array_ptr() { return &child_array; }
 
@@ -450,6 +462,8 @@ public:
   void append_hint_arguments(THD *thd, opt_hints_enum hint,
                              String *str) override;
 
+  void fix_hints_for_derived_table(TABLE_LIST *table_list);
+
   /**
     Function finds Opt_hints_table object corresponding to
     table alias in the query block and attaches corresponding
@@ -662,6 +676,20 @@ bool hint_key_state(const THD *thd, const TABLE *table,
                     uint keyno, opt_hints_enum type_arg,
                     uint optimizer_switch);
 
+/**
+  Returns table hint value if hint is specified, returns
+  fallback value if hint is not specified.
+
+  @param thd                Pointer to THD object
+  @param table_lsit         Pointer to TABLE_LIST object
+  @param type_arg           Hint type
+  @param fallback_value     Value to be returned if the hint is not set
+
+  @return table hint value if hint is specified,
+          otherwise fallback value.
+*/
+bool hint_table_state(const THD *thd, const TABLE_LIST *table_list,
+                      opt_hints_enum type_arg, bool fallback_value);
 
 /**
   Returns table hint value if hint is specified, returns

sql/opt_hints_parser.cc

@@ -71,6 +71,10 @@ Optimizer_hint_tokenizer::find_keyword(const LEX_CSTRING &str)
     if ("MRR"_Lex_ident_column.streq(str)) return TokenID::keyword_MRR;
     break;
 
+  case 5:
+    if ("MERGE"_Lex_ident_column.streq(str)) return TokenID::keyword_MERGE;
+    break;
+
   case 6:
     if ("NO_BKA"_Lex_ident_column.streq(str)) return TokenID::keyword_NO_BKA;
     if ("NO_BNL"_Lex_ident_column.streq(str)) return TokenID::keyword_NO_BNL;
@@ -88,6 +92,8 @@ Optimizer_hint_tokenizer::find_keyword(const LEX_CSTRING &str)
       return TokenID::keyword_SEMIJOIN;
     else if ("SUBQUERY"_Lex_ident_column.streq(str))
       return TokenID::keyword_SUBQUERY;
+    else if ("NO_MERGE"_Lex_ident_column.streq(str))
+      return TokenID::keyword_NO_MERGE;
     break;
 
   case 9:
@@ -134,6 +140,16 @@ Optimizer_hint_tokenizer::find_keyword(const LEX_CSTRING &str)
     if ("NO_RANGE_OPTIMIZATION"_Lex_ident_column.streq(str))
       return TokenID::keyword_NO_RANGE_OPTIMIZATION;
     break;
+
+  case 26:
+    if ("DERIVED_CONDITION_PUSHDOWN"_Lex_ident_column.streq(str))
+      return TokenID::keyword_DERIVED_CONDITION_PUSHDOWN;
+    break;
+
+  case 29:
+    if ("NO_DERIVED_CONDITION_PUSHDOWN"_Lex_ident_column.streq(str))
+      return TokenID::keyword_NO_DERIVED_CONDITION_PUSHDOWN;
+    break;
   }
 
   if (str.length > 0 && (str.str[0] >= '0' && str.str[0] <= '9'))
@@ -325,6 +341,22 @@ bool Parser::Table_level_hint::resolve(Parse_context *pc) const
     hint_type= BKA_HINT_ENUM;
     hint_state= false;
     break;
+  case TokenID::keyword_DERIVED_CONDITION_PUSHDOWN:
+     hint_type= DERIVED_CONDITION_PUSHDOWN_HINT_ENUM;
+     hint_state= true;
+     break;
+  case TokenID::keyword_NO_DERIVED_CONDITION_PUSHDOWN:
+     hint_type= DERIVED_CONDITION_PUSHDOWN_HINT_ENUM;
+     hint_state= false;
+     break;
+  case TokenID::keyword_MERGE:
+     hint_type= MERGE_HINT_ENUM;
+     hint_state= true;
+     break;
+  case TokenID::keyword_NO_MERGE:
+     hint_type= MERGE_HINT_ENUM;
+     hint_state= false;
+     break;
   default:
     DBUG_ASSERT(0);
     return true;

sql/opt_hints_parser.h

@@ -48,6 +48,8 @@ enum opt_hints_enum
   JOIN_SUFFIX_HINT_ENUM,
   JOIN_ORDER_HINT_ENUM,
   JOIN_FIXED_ORDER_HINT_ENUM,
+  DERIVED_CONDITION_PUSHDOWN_HINT_ENUM,
+  MERGE_HINT_ENUM,
   MAX_HINT_ENUM // This one must be the last in the list
 };
 
@@ -112,7 +114,11 @@ public:
     keyword_JOIN_PREFIX,
     keyword_JOIN_SUFFIX,
     keyword_JOIN_ORDER,
-    keyword_JOIN_FIXED_ORDER
+    keyword_JOIN_FIXED_ORDER,
+    keyword_DERIVED_CONDITION_PUSHDOWN,
+    keyword_NO_DERIVED_CONDITION_PUSHDOWN,
+    keyword_MERGE,
+    keyword_NO_MERGE
   };
 
   class Token: public Lex_cstring
@@ -363,7 +369,11 @@ private:
       return id == TokenID::keyword_BKA ||
              id == TokenID::keyword_BNL ||
              id == TokenID::keyword_NO_BKA ||
-             id == TokenID::keyword_NO_BNL;
+             id == TokenID::keyword_NO_BNL ||
+             id == TokenID::keyword_DERIVED_CONDITION_PUSHDOWN ||
+             id == TokenID::keyword_NO_DERIVED_CONDITION_PUSHDOWN ||
+             id == TokenID::keyword_MERGE ||
+             id == TokenID::keyword_NO_MERGE;
     }
   };
   class Table_level_hint_type: public TokenChoice<Parser,

sql/sql_select.cc

@@ -2513,43 +2513,42 @@ JOIN::optimize_inner()
       DBUG_RETURN(TRUE);
   }
 
-  if (optimizer_flag(thd, OPTIMIZER_SWITCH_COND_PUSHDOWN_FOR_DERIVED))
+  TABLE_LIST *tbl;
+  List_iterator_fast<TABLE_LIST> li(select_lex->leaf_tables);
+  while ((tbl= li++))
   {
-    TABLE_LIST *tbl;
+    const bool is_derived_pushdown_allowed= hint_table_state(
-    List_iterator_fast<TABLE_LIST> li(select_lex->leaf_tables);
+      thd, tbl->table, DERIVED_CONDITION_PUSHDOWN_HINT_ENUM,
-    while ((tbl= li++))
+      optimizer_flag(thd, OPTIMIZER_SWITCH_COND_PUSHDOWN_FOR_DERIVED));
+    if (!is_derived_pushdown_allowed)
     {
-      /* 
+      /* Run optimize phase on this derived table/view. */
+      if (tbl->is_view_or_derived() &&
+          tbl->handle_derived(thd->lex, DT_OPTIMIZE))
+        DBUG_RETURN(1);
+      continue;
+    }
+
+    if (tbl->is_materialized_derived())
+    {
+      JOIN *join= tbl->get_unit()->first_select()->join;
+      if (join &&
+          join->optimization_state == JOIN::OPTIMIZATION_PHASE_1_DONE &&
+          join->with_two_phase_optimization)
+        continue;
+      /*
         Do not push conditions from where into materialized inner tables
         of outer joins: this is not valid.
       */
-      if (tbl->is_materialized_derived())
+      if (!tbl->is_inner_table_of_outer_join())
       {
-        JOIN *join= tbl->get_unit()->first_select()->join;
+        if (pushdown_cond_for_derived(thd, conds, tbl))
-        if (join &&
+          DBUG_RETURN(1);
-            join->optimization_state == JOIN::OPTIMIZATION_PHASE_1_DONE &&
-            join->with_two_phase_optimization)
-          continue;
-        /*
-          Do not push conditions from where into materialized inner tables
-          of outer joins: this is not valid.
-        */
-        if (!tbl->is_inner_table_of_outer_join())
-	{
-          if (pushdown_cond_for_derived(thd, conds, tbl))
-	    DBUG_RETURN(1);
-        }
-	if (mysql_handle_single_derived(thd->lex, tbl, DT_OPTIMIZE))
-	  DBUG_RETURN(1);
       }
+      if (mysql_handle_single_derived(thd->lex, tbl, DT_OPTIMIZE))
+        DBUG_RETURN(1);
     }
   }
-  else
-  {
-    /* Run optimize phase for all derived tables/views used in this SELECT. */
-    if (select_lex->handle_derived(thd->lex, DT_OPTIMIZE))
-      DBUG_RETURN(1);
-  }
   {
     if (select_lex->where)
     {

sql/table.cc

@@ -57,6 +57,7 @@
 #endif
 #include "log_event.h"           // MAX_TABLE_MAP_ID
 #include "sql_class.h"
+#include "opt_hints.h"
 
 /* For MySQL 5.7 virtual fields */
 #define MYSQL57_GENERATED_FIELD 128
@@ -10105,6 +10106,19 @@ bool TABLE_LIST::init_derived(THD *thd, bool init_view)
     bool forced_no_merge_for_update_delete=
            belong_to_view ? belong_to_view->updating :
                            !unit->outer_select()->outer_select();
+
+    /*
+       In the case where a table merge operation moves a derived table from
+       one select to another, table hints may be adjusted already.
+    */
+    if (select_lex->opt_hints_qb &&    // QB hints initialized
+        !this->opt_hints_table)        // Table hints are not adjusted yet
+      select_lex->opt_hints_qb->fix_hints_for_derived_table(this);
+
+    bool is_derived_merge_allowed=
+        hint_table_state(thd, this, MERGE_HINT_ENUM,
+            optimizer_flag(thd, OPTIMIZER_SWITCH_DERIVED_MERGE));
+
     if (!is_materialized_derived() && unit->can_be_merged() &&
         /*
           Following is special case of
@@ -10121,7 +10135,7 @@ bool TABLE_LIST::init_derived(THD *thd, bool init_view)
          (!first_select->group_list.elements &&
           !first_select->order_list.elements)) &&
         (is_view() ||
-         optimizer_flag(thd, OPTIMIZER_SWITCH_DERIVED_MERGE)) &&
+         is_derived_merge_allowed) &&
           !thd->lex->can_not_use_merged() &&
         !(!is_view() && forced_no_merge_for_update_delete &&
           (thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||