Long UPDATE in postgresql

UPDATE pagelinks SET pl_to = page_id
    FROM page
    WHERE
        (pl_namespace, pl_title) = (page_namespace, page_title)
        AND
        page_is_redirect = 0
;

Merge Join  (cost=127710692.21..135714045.43 rows=452882848 width=57)
  Merge Cond: (("outer".page_namespace = "inner".pl_namespace) AND ("outer"."?column4?" = "inner"."?column5?"))
  ->  Sort  (cost=3193335.39..3219544.38 rows=10483593 width=41)
        Sort Key: page.page_namespace, (page.page_title)::text
        ->  Seq Scan on page  (cost=0.00..439678.01 rows=10483593 width=41)
              Filter: (page_is_redirect = 0::numeric)
  ->  Sort  (cost=124517356.82..125285665.74 rows=307323566 width=46)
        Sort Key: pagelinks.pl_namespace, (pagelinks.pl_title)::text"
        ->  Seq Scan on pagelinks  (cost=0.00..6169460.66 rows=307323566 width=46)

CREATE INDEX page_ns_title_idx on page(page_namespace, page_title);
CREATE INDEX pl_ns_title_idx on pagelink(pl_namespace, pl_title);
CREATE INDEX page_redir_idx on page(page_is_redirect);