Re: BUG #16089: Index only scan does not happen but expected - Mailing list pgsql-bugs

From Dmitry Dolgov
Subject Re: BUG #16089: Index only scan does not happen but expected
Date
Msg-id 20191030151439.gtfp77bef25za3n4@localhost
Whole thread Raw
In response to Re: BUG #16089: Index only scan does not happen but expected  (Dmitry Dolgov <9erthalion6@gmail.com>)
Responses RE: BUG #16089: Index only scan does not happen but expected
List pgsql-bugs
> On Wed, Oct 30, 2019 at 04:10:06PM +0100, Dmitry Dolgov wrote:
> > On Wed, Oct 30, 2019 at 02:18:09PM +0000, Stepan Yankevych wrote:
> >
> > >> And in fact at least in my tests this was indeed faster
> > Can you show execution plan when index is used?
> > Does it uses Index only scan or index scan and table scan?
> 
> Yes, at the bottom of the plan there was an Index Only Scan going
> through l1_snapshot_201811 (although while populating the table I've set
> values only for not nullable columns).

To clarify, Index Only Scan was there only after changing
random_page_cost/seq_page_cost. As I mentioned in the previous email,
original plan was also parallel seq scan.



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