MDEV-5535: Cannot reopen temporary table

mysqld maintains a list of TABLE objects for all temporary
tables created within a session in THD. Here each table is
represented by a TABLE object.

A query referencing a particular temporary table for more
than once, however, failed with ER_CANT_REOPEN_TABLE error
because a TABLE_SHARE was allocate together with the TABLE,
so temporary tables always had only one TABLE per TABLE_SHARE.

This patch lift this restriction by separating TABLE and
TABLE_SHARE objects and storing TABLE_SHAREs for temporary
tables in a list in THD, and TABLEs in a list within their
respective TABLE_SHAREs.

libmysqld/CMakeLists.txt

@@ -111,6 +111,7 @@ SET(SQL_EMBEDDED_SOURCES emb_qcache.cc libmysqld.c lib_sql.cc
            ../sql/wsrep_dummy.cc ../sql/encryption.cc
            ../sql/item_windowfunc.cc ../sql/sql_window.cc
            ../sql/sql_cte.cc
+           ../sql/temporary_tables.cc
            ${GEN_SOURCES}
            ${MYSYS_LIBWRAP_SOURCE}
 )

mysql-test/r/create.result

@@ -1736,7 +1736,8 @@ drop view t1;
 create table t1 (a int) select 1 as a;
 create temporary table if not exists t1 (a int) select * from t1;
 create temporary table if not exists t1 (a int) select * from t1;
-ERROR HY000: Can't reopen table: 't1'
+Warnings:
+Note	1050	Table 't1' already exists
 select * from t1;
 a
 1

mysql-test/r/lock.result

@@ -380,12 +380,7 @@ alter table t1 add column j int;
 unlock tables;
 drop table t1;
 create temporary table t1 (i int);
-#
-# This is just for test coverage purposes, 
-# when this is allowed, remove the --error.
-#
 lock tables t1 write, t1 as a read, t1 as b read;
-ERROR HY000: Can't reopen table: 't1'
 alter table t1 add column j int;
 unlock tables;
 drop table t1;

mysql-test/r/reopen_temp_table.result

@@ -0,0 +1,133 @@
+#
+# MDEV-5535: Cannot reopen temporary table
+#
+DROP DATABASE IF EXISTS temp_db;
+CREATE DATABASE temp_db;
+USE temp_db;
+#
+# Reopen temporary table
+#
+CREATE TEMPORARY TABLE t1(i int)ENGINE=INNODB;
+INSERT INTO t1 VALUES(1), (2);
+SELECT * FROM t1 a, t1 b;
+i	i
+1	1
+2	1
+1	2
+2	2
+DROP TABLE t1;
+#
+# CREATE & Stored routines
+#
+CREATE TEMPORARY TABLE t3 AS SELECT 1 AS a;
+CREATE PROCEDURE p1()
+BEGIN
+DROP TEMPORARY TABLE t3;
+end|
+CREATE FUNCTION f3() RETURNS INT
+BEGIN
+CALL p1();
+RETURN 1;
+END|
+PREPARE STMT FROM "SELECT f3() AS my_Column, a FROM t3";
+EXECUTE STMT;
+ERROR HY000: Can't reopen table: 't3'
+DROP TABLE t3;
+DROP FUNCTION f3;
+DROP PROCEDURE p1;
+CREATE TEMPORARY TABLE t4 (i INT);
+INSERT INTO t4 VALUES(1), (2);
+CREATE FUNCTION f4() RETURNS INT
+BEGIN
+DROP TEMPORARY TABLE t4;
+RETURN 1;
+END|
+SELECT f4() FROM t4;
+ERROR HY000: Can't reopen table: 't4'
+SELECT * FROM t4;
+i
+1
+2
+DROP TABLE t4;
+DROP FUNCTION f4;
+CREATE TEMPORARY TABLE t5 AS SELECT 1 AS a;
+CREATE PROCEDURE p2()
+BEGIN
+DROP TEMPORARY TABLE t5;
+END|
+CREATE FUNCTION f5() RETURNS INT
+BEGIN
+CALL p2();
+RETURN 1;
+END|
+SELECT f5() AS my_column, a FROM t5;
+ERROR HY000: Can't reopen table: 't5'
+DROP TABLE t5;
+DROP FUNCTION f5;
+DROP PROCEDURE p2;
+#
+# CTAS
+#
+CREATE TABLE t1(i INT);
+INSERT INTO t1 VALUES(1), (2);
+CREATE TEMPORARY TABLE t1
+SELECT temp_1.i a, temp_2.i b FROM t1 AS temp_1, t1 AS temp_2;
+SELECT * FROM t1;
+a	b
+1	1
+2	1
+1	2
+2	2
+DROP TABLE t1;
+SELECT * FROM t1;
+i
+1
+2
+DROP TABLE t1;
+#
+# HANDLER
+#
+CREATE TABLE t1 (a INT, KEY a(a));
+INSERT INTO t1 (a) VALUES (1), (2), (3), (4), (5);
+CREATE TABLE t2 (a INT, KEY a (a)) SELECT * FROM t1;
+CREATE TEMPORARY TABLE t3 (a INT, KEY a (a)) SELECT * FROM t2;
+HANDLER t3 OPEN;
+SELECT * FROM t1;
+a
+1
+2
+3
+4
+5
+LOCK TABLE t1 READ;
+HANDLER t3 OPEN;
+ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
+UNLOCK TABLES;
+HANDLER t3 OPEN;
+ERROR 42000: Not unique table/alias: 't3'
+HANDLER t3 READ NEXT;
+a
+1
+HANDLER t3 OPEN AS t3_1;
+HANDLER t3_1 READ NEXT;
+a
+1
+HANDLER t3_1 READ NEXT;
+a
+2
+HANDLER t3 CLOSE;
+HANDLER t3_1 CLOSE;
+DROP TEMPORARY TABLE t3;
+DROP TABLE t1, t2;
+#
+# INSERT-SELECT
+#
+CREATE TEMPORARY TABLE t4 (a INT) ENGINE=MYISAM;
+INSERT INTO t4 VALUES(1), (2);
+INSERT INTO t4 SELECT * FROM t4;
+SELECT COUNT(*) FROM t4;
+COUNT(*)
+4
+DROP TABLE t4;
+# Cleanup
+DROP DATABASE temp_db;

mysql-test/r/sp.result

@@ -1140,9 +1140,12 @@ insert into t3 values (1), (2), (3);
 return (select count(*) from t3 as a, t3 as b);
 end|
 select f11()|
-ERROR HY000: Can't reopen table: 'a'
+f11()
+9
 select f11() from t1|
-ERROR HY000: Can't reopen table: 'a'
+f11()
+9
+9
 create function f12_1() returns int
 begin
 drop temporary table if exists t3;
@@ -1156,6 +1159,7 @@ drop temporary table t3|
 select f12_1()|
 f12_1()
 3
+drop temporary table t3|
 select f12_1() from t1 limit 1|
 f12_1()
 3
@@ -6933,7 +6937,7 @@ CREATE TEMPORARY TABLE t3 LIKE t1;
 CREATE PROCEDURE p1 () BEGIN SELECT f1 FROM t3 AS A WHERE A.f1 IN ( SELECT f1 FROM t3 ) ;
 END|
 CALL p1;
-ERROR HY000: Can't reopen table: 'A'
+f1
 CREATE VIEW t3 AS SELECT f1 FROM t2 A WHERE A.f1 IN ( SELECT f1 FROM t2 );
 DROP TABLE t3;
 CALL p1;

mysql-test/suite/handler/aria.result

@@ -632,7 +632,18 @@ handler a1 read a next;
 a	b
 3	d
 select a,b from t1;
-ERROR HY000: Can't reopen table: 'a1'
+a	b
+0	a
+1	b
+2	c
+3	d
+4	e
+5	f
+6	g
+7	h
+8	i
+9	j
+9	k
 handler a1 read a prev;
 a	b
 2	c
@@ -745,7 +756,7 @@ ERROR HY000: Can't execute the given command because you have active locked tabl
 handler t2 close;
 ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
 handler t3 open;
-ERROR HY000: Can't reopen table: 't3'
+ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
 # After UNLOCK TABLES handlers should be around and
 # we should be able to continue reading through them.
 unlock tables;
@@ -1396,7 +1407,12 @@ handler t2 read a next;
 a	b
 3	NULL
 select * from t2;
-ERROR HY000: Can't reopen table: 't2'
+a	b
+1	NULL
+2	NULL
+3	NULL
+4	NULL
+5	NULL
 handler t2 read a next;
 a	b
 4	NULL

mysql-test/suite/handler/handler.inc

@@ -460,9 +460,6 @@ drop table t1;
 #
 # Bug#30882 Dropping a temporary table inside a stored function may cause a server crash
 #
-# Test HANDLER statements in conjunction with temporary tables. While the temporary table
-# is open by a HANDLER, no other statement can access it.
-#
 
 create temporary table t1 (a int, b char(1), key a using btree (a), key b using btree (a,b));
 insert into t1 values (0,"a"),(1,"b"),(2,"c"),(3,"d"),(4,"e"),
@@ -472,7 +469,6 @@ handler t1 open as a1;
 handler a1 read a=(1);
 handler a1 read a next;
 handler a1 read a next;
---error ER_CANT_REOPEN_TABLE
 select a,b from t1;
 handler a1 read a prev;
 handler a1 read a prev;
@@ -564,7 +560,7 @@ handler t1 open;
 handler t1 read next;
 --error ER_LOCK_OR_ACTIVE_TRANSACTION
 handler t2 close;
---error ER_CANT_REOPEN_TABLE
+--error ER_LOCK_OR_ACTIVE_TRANSACTION
 handler t3 open;
 --echo # After UNLOCK TABLES handlers should be around and
 --echo # we should be able to continue reading through them.
@@ -1182,7 +1178,6 @@ handler t1 read a next;
 select * from t1;
 --echo # Sic: the position is not lost
 handler t2 read a next;
---error ER_CANT_REOPEN_TABLE
 select * from t2;
 handler t2 read a next;
 drop table t1;

mysql-test/suite/handler/heap.result

@@ -632,7 +632,18 @@ handler a1 read a next;
 a	b
 3	d
 select a,b from t1;
-ERROR HY000: Can't reopen table: 'a1'
+a	b
+0	a
+1	b
+2	c
+3	d
+4	e
+5	f
+6	g
+7	h
+8	i
+9	j
+9	k
 handler a1 read a prev;
 a	b
 2	c
@@ -745,7 +756,7 @@ ERROR HY000: Can't execute the given command because you have active locked tabl
 handler t2 close;
 ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
 handler t3 open;
-ERROR HY000: Can't reopen table: 't3'
+ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
 # After UNLOCK TABLES handlers should be around and
 # we should be able to continue reading through them.
 unlock tables;
@@ -1396,7 +1407,12 @@ handler t2 read a next;
 a	b
 3	NULL
 select * from t2;
-ERROR HY000: Can't reopen table: 't2'
+a	b
+1	NULL
+2	NULL
+3	NULL
+4	NULL
+5	NULL
 handler t2 read a next;
 a	b
 4	NULL

mysql-test/suite/handler/innodb.result

@@ -633,7 +633,18 @@ handler a1 read a next;
 a	b
 3	d
 select a,b from t1;
-ERROR HY000: Can't reopen table: 'a1'
+a	b
+0	a
+1	b
+2	c
+3	d
+4	e
+5	f
+6	g
+7	h
+8	i
+9	j
+9	k
 handler a1 read a prev;
 a	b
 2	c
@@ -747,7 +758,7 @@ ERROR HY000: Can't execute the given command because you have active locked tabl
 handler t2 close;
 ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
 handler t3 open;
-ERROR HY000: Can't reopen table: 't3'
+ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
 # After UNLOCK TABLES handlers should be around and
 # we should be able to continue reading through them.
 unlock tables;
@@ -1400,7 +1411,12 @@ handler t2 read a next;
 a	b
 3	NULL
 select * from t2;
-ERROR HY000: Can't reopen table: 't2'
+a	b
+1	NULL
+2	NULL
+3	NULL
+4	NULL
+5	NULL
 handler t2 read a next;
 a	b
 4	NULL