Re: Anything to be gained from a 'Postgres Filesystem'?

After a long battle with technology, simon(at)2ndquadrant(dot)com (Simon Riggs), an earthling, wrote:
> On Thu, 2004-11-04 at 15:47, Chris Browne wrote:
>
>> Another thing that would be valuable would be to have some way to say:
>>
>> "Read this data; don't bother throwing other data out of the cache
>> to stuff this in."
>>
>> Something like a "read_uncached()" call...
>>
>> That would mean that a seq scan or a vacuum wouldn't force useful
>> data out of cache.
>
> ARC does almost exactly those two things in 8.0.
>
> Seq scans do get put in cache, but in a way that means they don't
> spoil the main bulk of the cache.

We're not talking about the same cache.

ARC does these exact things for _shared memory_ cache, and is the
obvious inspiration.

But it does more or less nothing about the way OS file buffer cache is
managed, and the handling of _that_ would be the point of modifying OS
filesystem semantics.
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