Re: [v9.1] sepgsql - userspace access vector cache

On Thu, Jul 21, 2011 at 3:25 PM, Yeb Havinga <yebhavinga@gmail.com> wrote:
> Is it possible to only include the syscache on --enable-selinux
> configurations? It would imply physical data incompatibility with standard
> configurations, but that's also true for e.g. the block size.

Not really.  SECURITY LABEL is supposedly a generic facility that can
be used by a variety of providers, and the regression tests load a
dummy provider which works on any platform to test that it hasn't
gotten broken.

> Also, the tests I did with varying bucket sizes suggested that decreasing
> the syscache to 256 didn't show a significant performance decrease compared
> to the 2048 #buckets, for the restorecon test, which hits over 3000 objects
> with security labels. My guess is that that is a fair middle of the road
> database schema size. Are you unwilling to pay the startup overhead for a
> extra 256 syscache?

Not sure.  I'd rather not, if it's easy to rejigger things so we don't
have to.  I don't think this is necessarily a hard problem to solve -
it's just that no one has tried yet.

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