| From: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> |
|---|---|
| To: | Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "REIX, Tony" <tony(dot)reix(at)atos(dot)net>, Andres Freund <andres(at)anarazel(dot)de>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>, "EMPEREUR-MOT, SYLVIE" <sylvie(dot)empereur-mot(at)atos(dot)net> |
| Subject: | Re: Shared Memory: How to use SYSV rather than MMAP ? |
| Date: | 2019-01-04 15:39:06 |
| Message-ID: | 8c5f76e4-3541-c7f9-82d3-fd2863817598@2ndquadrant.com |
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| Lists: | pgsql-hackers |
On 27/12/2018 00:53, Thomas Munro wrote:
> mmap and sysv were the same, but there
> did seem to be a measurable speed-up available at high client counts
> with kern.ipc.shm_use_phys=1 and thus for sysv only, for people
> prepared to set 3 sysctls and this proposed new GUC. Maybe the effect
> would be greater with bigger shared_buffers or smaller pages (this
> test ran on super pages)? More work required to figure that out.
Could you get a similar effect for mmap by using mlock() to prevent the
pages from being swapped?
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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