"Ara Anjargolian" <ara(at)jargol(dot)com> writes:
> jargol=# explain select user_id, first_names, last_name from articles, users
> where article_id = 5027 and (articles.author_id1 = users.user_id or
> articles.author_id2 = users.user_id);
> Why does it think it MUST do a seq-scan in the second case?
There's no support for generating an OR indexscan in the context of a
join.
regards, tom lane