postgres=# create index idx on t using lsm3(id) with (unique=true);
postgres=# insert into t select generate_series(1,10000000), md5(random()::text);
postgres=# \dt+ t
List of relations
Schema | Name | Type | Owner | Persistence | Size | Description
--------+------+-------+----------+-------------+--------+-------------
public | t | table | postgres | permanent | 651 MB |
public | idx | index | postgres | t | permanent | 69 GB |
HI, lsm3 index more larger than btree index: