CREATE TABLE t1(a int) ENGINE=BLACKHOLE;
Warnings:
Warning	1286	Unknown storage engine 'BLACKHOLE'
Warning	1266	Using storage engine MyISAM for table 't1'
DROP TABLE t1;
INSTALL PLUGIN blackhole SONAME 'ha_blackhole.so';
INSTALL PLUGIN BLACKHOLE SONAME 'ha_blackhole.so';
ERROR HY000: Function 'BLACKHOLE' already exists
UNINSTALL PLUGIN blackhole;
INSTALL PLUGIN blackhole SONAME 'ha_blackhole.so';
CREATE TABLE t1(a int) ENGINE=BLACKHOLE;
DROP TABLE t1;
SELECT 1;
1
1
UNINSTALL PLUGIN blackhole;
UNINSTALL PLUGIN blackhole;
ERROR 42000: PLUGIN blackhole does not exist