Re: UNION causes horrible plan on JOIN
Justin Pryzby <[email protected]> Mon, 28 Oct 2019 17:45:53 -0500
| Newsgroups | gmane.comp.db.postgresql.performance |
|---|---|
| Message-ID | <[email protected]> |
On Mon, Oct 28, 2019 at 03:40:58PM -0700, Craig James wrote: > On Postgres 9.6 (config below), I have a case I don't understand: three > tables that can be separately queried in milliseconds, but when put > together into one view using UNION, take 150 seconds to query. Here's the > rough idea (actual details below): Do you want UNION ALL ? UNION without ALL distintifies the output. https://www.postgresql.org/docs/current/sql-select.html#SQL-UNION Justin