Re: custom function for converting human readable sizes to bytes

2016-01-04 21:29 GMT+01:00 Robert Haas <robertmhaas(at)gmail(dot)com>:

> On Mon, Jan 4, 2016 at 12:17 PM, Shulgin, Oleksandr
> <oleksandr(dot)shulgin(at)zalando(dot)de> wrote:
> >> I'm also kind of wondering what the intended use case for this
> >> function is. Why do we want it? Do we want it?
> >
> > As suggested above a usecase could be like the following:
> >
> > SELECT relname FROM pg_class WHERE pg_relation_size(oid) >
> > pg_size_bytes('100 GB');
> >
> > I think it's neat and useful.
>
> But you could also write SELECT relname FROM pg_class WHERE
> pg_relation_size(oid) > 100 * 1024^3, which is actually fewer
> characters. Maybe pg_size_bytes('100 GB') is easier for some people
> to remember than 100 * 1024^3, but I'm probably not one of those
> people.
>

I am really one who hasn't memory for numbers - "100GB" is much more
verbose for me. It is more clean in more complex maintenance queries. And
if you need short syntax, you can write own SQL function

CREATE OR REPLACE FUNCTION size(text) RETURNS bigint AS $$ SELECT
pg_size_bytes($1) $$ LANGUAGE sql;

then ... pg_relation_size(oid) > size('100GB')

Regards

Pavel

>
> --
> Robert Haas
> EnterpriseDB: http://www.enterprisedb.com
> The Enterprise PostgreSQL Company
>