Message-ID: <4E6CC458.4010206@squeakycode.net>
Date: Sun, 11 Sep 2011 09:23:20 -0500
From: Andy Colson <andy@squeakycode.net>
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To: Igor Chudov <ichudov@gmail.com>
CC: pgsql-performance@postgresql.org
Subject: Re: Postgres for a "data warehouse", 5-10 TB
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On 09/11/2011 08:59 AM, Igor Chudov wrote:
>
>
> I do not plan to do a lot of random writing. My current design is that my perl scripts write to a temporary table every week, and then I do INSERT..ON DUPLICATE KEY UPDATE.
>
> By the way, does that INSERT UPDATE functionality or something like this exist in Postgres?
>
> i

You have two options:

1) write a function like:
create function doinsert(_id integer, _value text) returns void as $$
begin
   update thetable set value = _value where id = _id;
   if not found then
      insert into thetable(id, value) values (_id, _value);
    end if
end;
$$ language plpgsql;

2) use two sql statements:
-- update the existing
update realTable set value = (select value from tmp where tmp.id = realTable.id)
where exists (select value from tmp where tmp.id = realTable.id);

-- insert the missing
insert into realTable(id, value)
select id, value from tmp where not exists(select 1 from realTable where tmp.id = realTable.id);


-Andy