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.

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

mysql-test/suite/handler/myisam.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