create table t1(a blob) engine=innodb key_block_size=8;
create function generate_blob()
returns varchar(20000)
begin
declare x varchar(20000) default '';
declare i int default 500;
while i > 0 do
set x = concat(sha1(i), x);
set i = i - 1;
end while;
return x;
end //
insert into t1 select generate_blob();
truncate t1;
insert into t1 select generate_blob();
drop table t1;
drop function generate_blob;