| From: | Jonathan Vanasco <postgres(at)2xlp(dot)com> |
|---|---|
| To: | PostgreSQL mailing lists <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: newsfeed type query |
| Date: | 2015-04-30 17:08:19 |
| Message-ID: | 31D4D498-4B17-4239-835D-F604C193ABA2@2xlp.com |
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| Lists: | pgsql-general |
On Apr 29, 2015, at 6:50 PM, Jim Nasby wrote:
> Only because you're using UNION. Use UNION ALL instead.
The difference between "union" and "union all" was negligible. the problem was in the subselect and the sheer size of the tables, even when we could handle it as an index-only scan.
On Apr 29, 2015, at 1:18 PM, Ladislav Lenart wrote:
> I would expect the overall query to return only 60F nad 55F as the most recent
> data. No? You expect it to return 4 items when the LIMIT is only 2. Remember
> that the overall query should be also ordered by ts and limited to 2.
You're right. total mistake on my part and confusion with that. I got this query confused with the specifics of a similar one.
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