Re: Query taking seq scan on a table

Hello,

It worked fine for me.
Thanks for the correction and all the help!

On Tue, Sep 22, 2020 at 7:37 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> 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
>