...and a question (SHA1 UUIDs)

Bron Gondwana brong at fastmail.fm
Thu Sep 6 10:09:15 EDT 2007

On Thu, 06 Sep 2007 09:53:27 -0400, "Ken Murchison" <murch at andrew.cmu.edu> said:
> Bron Gondwana wrote:
> > I guess there's still some value in having a "turn UUIDs off" config
> > option to allow people who don't want the CPU overhead of calculating
> > sha1 values to avoid it.  Unless we're planning to simplify the
> > replication system as well by absolutely demanding that UUIDs are
> > calculated on all messages.  I can see arguments for both sides, so
> > I guess it's down to an executive decision!
> Right.  It comes down to whether we want/need to allow replication 
> without UUIDs.  We can trigger whether we calculate the SHA1 UUIDs on 
> the master by checking to see if 'sync_host' is set.

There's some value anyway for integrity checks.

> If we go with a 'uuid_mode' option, my inclination is default it to 
> 'none' or 'off', so standalone servers aren't wasting CPU by doing SHA1 
> (or else we couple check for 'sync_host' && 'uuid_mode' before doing
> SHA1).

I'd be inclined to make them two separate choices, because sha1 in the
index is still very valuable for integrity checks and potentially
duplicate finding (post dated "single instance store" even!)

  Bron Gondwana
  brong at fastmail.fm

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