From: | Rick Otten <rottenwindfish(at)gmail(dot)com> |
---|---|
To: | greatvovan(at)gmail(dot)com |
Cc: | andrew(at)tao11(dot)riddles(dot)org(dot)uk, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-performance(at)lists(dot)postgresql(dot)org |
Subject: | Re: Why Postgres doesn't use TID scan? |
Date: | 2018-12-20 13:46:04 |
Message-ID: | CAMAYy4KC+epqkZLgxgyv+hy9Cwp+RwjuaO_7mb0HhPZC+74TrQ@mail.gmail.com |
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Thread: | |
Lists: | pgsql-performance |
On Wed, Dec 19, 2018 at 6:45 PM Vladimir Ryabtsev <greatvovan(at)gmail(dot)com>
wrote:
> > The fundamental issue is that "ANY" has two meanings in PG, one of them
> following the SQL standard and one not:
>
> Oh yes, I was aware about two forms but it did not come into my mind, I
> was thinking I use the same form in both cases since my query returns only
> one row and column.
> Thanks for pointing me into that.
>
> --
> Vlad
>
For what it is worth, I have found that if I am checking for the presence
of an object in an array, while this syntax is easy to understand and more
intuitive to craft:
select
*
from
mytable
where
' test' = ANY (my_varchar_array_column)
;
This syntax is almost always much faster:
select
*
from
mytable
where
ARRAY['test'::varchar] <@ my_varchar_array_column
;
(Since this is a performance list after all.)
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