Viktor Rosenfeld <-berlin.de> writes:
> -> Seq Scan on corpus toplevel (cost=0.00..1.39 rows=1 width=54)
> Filter: (top_level AND (id = 25::numeric))
> Specifically, I'm wondering why the innermost scan on corpus
> (toplevel) does not use the index idx_corpus__toplevel
The cost estimate indicates that there are so few rows in corpus
that an indexscan would be a waste of time.
> and why the
> join between corpus (toplevel) and corpus (child) is not a merge join
> using the index corpus_pre_key to access the child table.
Same answer. Populate the table and the plan will change.
regards, tom lane