Re: Query slows when used with view - Mailing list pgsql-performance

From Michael Lewis
Subject Re: Query slows when used with view
Date
Msg-id CAHOFxGpi_CnCPhLr0ebudxm7Y0gpP1TTrRwDyfdUTv9Hn9WWoQ@mail.gmail.com
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In response to Re: Query slows when used with view  (Jeff Janes <jeff.janes@gmail.com>)
Responses Re: Query slows when used with view  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
When you join to a view, the view sticks together, as if they were all in parentheses.   But when you substitute the text of a view into another query, then they are all on the same level and can be parsed differently.

Consider the difference between "1+1 * 3", and "(1+1) * 3"

I thought from_collapse_limit being high enough meant that it will get re-written and inlined into the same level. To extend your metaphor, that it would be 1 * 3 + 1 * 3.

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