Re: Free WAL caches on switching segments

ITAGAKI Takahiro wrote:
> Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> > > Here is a small patch to prevent undesired WAL file caching by kernel.
> > > posix_fadvise(POSIX_FADV_DONTNEED) attempts to free cached pages and
> > > the kernel will discard them in preference to other data caches.
> >
> > On plenty of platforms, this won't even compile ...
>
>
> Do you mean simply following code? or more pretty way?
>
> #ifdef POSIX_FADV_DONTNEED
>     posix_fadvise(openLogFile, 0, 0, POSIX_FADV_DONTNEED);
> #endif

Yes, but we probably have to have a configure test to see if
posix_fadvise exists too.  I will keep this for 8.2.

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