Re: Updates, deletes and inserts are very slow. What can I do make them bearable?

>
> No, it isn't.  This is a three-way join between consolidated_urls, cu,
> and tu --- the fact that cu is the same underlying table as

cu is an alias for consolidated_urls. tu is an alias for trending_urls.

There are only two tables in the query.

> consolidated_urls doesn't change that.  And the join is
> underconstrained, causing each row of consolidated_urls to be joined
> to every row of the cu/tu join.  That's why it's taking such an
> unreasonably long time --- you're generating many thousands of redundant
> updates to each row of consolidated_urls.  You should just write this as
>

Once again there are only two tables in the query. The join clause is
inner join trending_urls tu on tu.consolidated_url_id = cu.id

> update consolidated_urls
> set screenshot_file_name = tu.screenshot_file_name,
>   screenshot_content_type  = tu.screenshot_content_type,
>   screenshot_file_size = tu.screenshot_file_size,
>   screenshot_status  = tu.screenshot_status
> from trending_urls tu where tu.consolidated_url_id = consolidated_urls.id
>
> Postgres is a bit different from some other DBMSes in how it interprets
> UPDATE ... FROM syntax.
>

I'll try this too.

Anything to make this query complete in a reasonable amount of time.