Re: BUG #13817: Query planner strange choose while select/count small part of big table - complete

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От Marcin Sieńko
Тема Re: BUG #13817: Query planner strange choose while select/count small part of big table - complete
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Msg-id CAButoGESvhOqUdREmFjNH_zsWSKty0PSmxYPw0ZB3cYEqNfD+A@mail.gmail.com
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Ответ на Re: BUG #13817: Query planner strange choose while select/count small part of big table - complete  ("Peter J. Holzer" <hjp-pgsql@hjp.at>)
Ответы Re: BUG #13817: Query planner strange choose while select/count small part of big table - complete  ("Peter J. Holzer" <hjp-pgsql@hjp.at>)
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Hi,

On 9.5 beta it still works similar. Did You see my last reply?:

I've done it already. I've also already check rewrited query. No changes. But i have a idea. There is generated base and there are "normal" shipment_order_item with 3 - 100 maybe 10000 shipment_order_sub_item but one has 3 992 102. Could it be a problem?

If yes that is my bad to ask You because I'belive there will not occur in production and counting could bye match faster.

I think it could be this problem. Additional I checked number of sub items and there is 6 items and 5 contains 2 sub items and 1 contains 3 992 102 sub items. For me that is only "not normal" data problem and i think it will be working correct when  data is normal.

P.S. I checked all cases on 9.5 and there are no differences.

Regards,
Marcin

2015-12-18 8:09 GMT+01:00 Peter J. Holzer <hjp-pgsql@hjp.at>:
On 2015-12-14 11:45:27 +0000, sienkomarcin@gmail.com wrote:
> The following bug has been logged on the website:
>
> Bug reference:      13817
> Logged by:          Marcin_S
> Email address:      sienkomarcin@gmail.com
> PostgreSQL version: 9.4.5
> Operating system:   Windows 7 x64
> Description:
>
> Hi,
>
> First sorry for not completed last bug (browser handle it too fast :). Here
> is complete version:
>
>
> I've check todo list but i can't find exact problem i'm reporting. It seems
> like query planner fires not needed sequence scan by all rows in table when
> only a few rows were picked.

Can you try this with version 9.5 (currently in beta)? This looks very
similar to a problem I reported some time ago and which is fixed in 9.5.

        hp

--
   _  | Peter J. Holzer    | I want to forget all about both belts and
|_|_) |                    | suspenders; instead, I want to buy pants
| |   | hjp@hjp.at         | that actually fit.
__/   | http://www.hjp.at/ |   -- http://noncombatant.org/

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