postgres=# EXPLAIN ANALYZE select (regexp_split_to_array('wqer  wetr кеке werwerw ' || i, '\s+'))[2] from generate_series(1, 100000) as i;
                                                         QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------
 Function Scan on generate_series i  (cost=0.00..20.00 rows=1000 width=4) (actual time=15.396..1115.696 rows=100000 loops=1)
 Total runtime: 1131.406 ms
(2 rows)

postgres=# EXPLAIN ANALYZE select split_part(regexp_replace('wqer  wetr кеке werwerw ' || i, '\s+', ' '), ' ', 2) from generate_series(1, 100000) as i;
                                                         QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
 Function Scan on generate_series i  (cost=0.00..22.50 rows=1000 width=4) (actual time=15.367..286.597 rows=100000 loops=1)
 Total runtime: 295.583 ms
(2 rows)