Re: Why we are going to have to go DirectIO

On Tue, Dec 3, 2013 at 1:44 PM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
> All,
>
> https://lkml.org/lkml/2013/11/24/133
>
> What this means for us:
>
> http://citusdata.com/blog/72-linux-memory-manager-and-your-big-data
>
> It seems clear that Kernel.org, since 2.6, has been in the business of
> pushing major, hackish, changes to the IO stack without testing them or
> even thinking too hard about what the side-effects might be. This is
> perhaps unsurprising given that two of the largest sponsors of the
> Kernel -- who, incidentally, do 100% of the performance testing -- don't
> use the IO stack.
>
> This says to me that Linux will clearly be an undependable platform in
> the future with the potential to destroy PostgreSQL performance without
> warning, leaving us scrambling for workarounds. Too bad the
> alternatives are so unpopular.
>
> I don't know where we'll get the resources to implement our own storage,
> but it's looking like we don't have a choice.

This seems like a strange reaction to an article that's mostly about
how Linux is now *fixing* a problem that could cause PostgreSQL to
experience performance problems. I agree that we'll probably
eventually need to implement our own storage layer, but this article
isn't evidence of urgency so far as I can determine on first
read-through.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company