install plugin innodb soname 'ha_innodb';
create table t1(a int not null primary key) engine=innodb;
begin;
insert into t1 values(1);
flush tables;
uninstall plugin innodb;
select sleep(1);
sleep(1)
0
Warnings:
Warning	1620	Plugin is busy and will be uninstalled on shutdown
drop table t1;
install plugin innodb soname 'ha_innodb';
create table t2(a int not null primary key) engine=innodb;
insert into t2 values(1);
drop table t2;
uninstall plugin innodb;
select sleep(1);
sleep(1)
0
Warnings:
Warning	1620	Plugin is busy and will be uninstalled on shutdown