Re: Query taking seq scan on a table

Shrikant Bhende <shrikantpostgresql(at)gmail(dot)com> writes:
> *create index concurrently lname_test_btree_txt_pat_ops on wldbowner.member
> (lname text_pattern_ops) where fname like LOWER(unaccent_string(lname) ||
> '%')*
> Is this the correct way to create a b-tree index with text_pattern_ops for
> my requirement ?

No. What you're trying to optimize is

Filter: ((lower(unaccent_string((lname)::text))
~~ 'info%'::text) AND (lower(unaccent_string((fname)::text)) ~~
'travel%'::text))

so you need one or both of

create index on member (lower(unaccent_string(lname)) text_pattern_ops);
create index on member (lower(unaccent_string(fname)) text_pattern_ops);

If one of those two conditions is reliably more selective than the
other, perhaps just one index would do.

regards, tom lane