Re: Experimental patch for inter-page delay in VACUUM - Mailing list pgsql-hackers

From Neil Conway
Subject Re: Experimental patch for inter-page delay in VACUUM
Date
Msg-id 871xsg18j6.fsf@mailbox.samurai.com
Whole thread Raw
In response to Re: Experimental patch for inter-page delay in VACUUM  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: Experimental patch for inter-page delay in VACUUM
List pgsql-hackers
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Now, the disadvantages of large kernel cache, small PostgreSQL buffer
> cache is that data has to be transfered to/from the kernel buffers, and
> second, we can't control the kernel's cache replacement strategy, and
> will probably not be able to in the near future, while we do control our
> own buffer cache replacement strategy.

The intent of the posix_fadvise() work is to at least provide a
few hints about our I/O patterns to the kernel's buffer
cache. Although only Linux supports it (right now), that should
hopefully improve the status quo for a fairly significant portion of
our user base.

I'd be curious to see a comparison of the cost of transferring data
from the kernel's buffers to the PG bufmgr.

-Neil



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