svn commit: r280323 - head/sys/kern

[Dmitry Morozovsky]

On Sat, 21 Mar 2015, Konstantin Belousov wrote:

> > > > >   Somewhat modernize the SysV shm code:
> > > > 
> > > > Is my understanding correct that postgres still uses shm?  If so,
> > > > has someone benchmarked the speedup?
> > > 
> > > Yes, some versions of Postgres still use SysV shm.  
> > 
> > To be clarified: IIUC, *all* contemporary versions of PostgreSQL do
> > use SHM for shatrd buffers (as PgSQL use process-per-connection model)
>
> No.  Recent versions use mmaped shared region for buffers.

Yes, starting from 9.3 main buffers are memory-mapped.  SysV SHM and Semaphores 
*are* still in use though.

(mainly for search engines)

Thanks for the clarification.

-- 
Sincerely,
D.Marck                                     [DM5020, MCK-RIPE, DM3-RIPN]
[ FreeBSD committer:                                 marck at FreeBSD.org ]
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*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck at rinet.ru ***
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