| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Heikki Linnakangas <hlinnaka(at)iki(dot)fi> |
| Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Sort performance cliff with small work_mem |
| Date: | 2018-05-02 15:46:30 |
| Message-ID: | CA+Tgmob-_MwpkXpKAGWs8-_m4Ph=zgqL7ZnHywgCGeP0h8i-BA@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Wed, May 2, 2018 at 11:38 AM, Heikki Linnakangas <hlinnaka(at)iki(dot)fi> wrote:
> To fix, I propose that we change the above so that we always subtract
> tapeSpace, but if there is less than e.g. 32 kB of memory left after that
> (including, if it went below 0), then we bump availMem back up to 32 kB. So
> we'd always reserve 32 kB to hold the tuples, even if that means that we
> exceed 'work_mem' slightly.
Sounds very reasonable.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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