Re: Index Skip Scan - Mailing list pgsql-hackers

From Dmitry Dolgov
Subject Re: Index Skip Scan
Date
Msg-id CA+q6zcVFc3+Wm_EfsEif5oy9HKxA+wm9Z2iPSzecSCBKANg5Mw@mail.gmail.com
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In response to Re: Index Skip Scan  (Dmitry Dolgov <9erthalion6@gmail.com>)
Responses Re: Index Skip Scan  (Dmitry Dolgov <9erthalion6@gmail.com>)
List pgsql-hackers
> On Thu, Dec 20, 2018 at 2:46 PM Dmitry Dolgov <9erthalion6@gmail.com> wrote:
>
> I've performed some testing, and on my environment with a dataset of 10^7
> records:
>
> * everything below 7.5 * 10^5 unique records out of 10^7 was faster with skip
>   scan.
>
> * above 7.5 * 10^5 unique records skip scan was slower, e.g. for 10^6 unique
>   records it was about 20% slower than the regular index scan.
>
> For me these numbers sound good, since even in quite extreme case of
> approximately 10 records per group the performance of index skip scan is close
> to the same for the regular index only scan.

Rebased version after rd_amroutine was renamed.

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