Re: Create one query out of two

What does EXPLAIN show?

What proportion of contacts have owner_id=7 and user_id is null?

If it's a large number of contacts, I'd try the following:

create temporary table tusers as
select coalesce(p.ref_contact_id,e.ref_contact_id) as id, u.id as user_id
from my_users u
left join phone_number p on on p.significant=u.phone_significant
left join email_addresses e on e.email=u.email
where p.ref_contact_id is not null or e.ref_contact_id is not null;

create unique index tusers_idx on tusers(id);

update contacts set user_id=t.user_id
from tusers t
where t.id=contacts.id and contacts.owner=7 and contacts.user_id is null;

If it's a small number of contacts, then it might be worth creating a
temporary table of that subset, indexing it, then replacing "where
p.ref_contact_id is not null or e.ref_contact_id is not null" with "where
p.ref_contact_id in (select id from TEMPTABLE) or e.ref_contact_id in
(select id from TEMPTABLE)"

Calvin Dodge

On Sat, Aug 17, 2013 at 3:19 PM, Robert DiFalco <robert(dot)difalco(at)gmail(dot)com>wrote:

> Currently I run two queries back-to-back to correlate users with contacts.
>
> UPDATE contacts SET user_id = u.id
> FROM my_users u
> JOIN phone_numbers pn ON u.phone_significant = pn.significant
> WHERE contacts.owner_id = 7 AND contacts.user_id IS NULL AND
> contacts.id = pn.ref_contact_id;
>
> UPDATE contacts SET user_id = u.id
> FROM my_users u
> JOIN email_addresses em ON u.email = em.email
> WHERE contacts.owner_id = 7 AND contacts.user_id IS NULL AND
> contacts.id = em.ref_contact_id;
>
> For some reason I cannot figure out how to combine these into one update
> query. They are running slower than I'd like them to even though I have
> indices on user_id, owner_id, email, and significant. So I'd like to try
> them in a single query to see if that helps.
>
> As always, thanks for your sage advice.
>