Re: [sqlite] Multi-master replication with updated Versioning extension

On Thu, Jul 30, 2009 at 06:11:42PM +0400, Alexey Pechnikov scratched on the 
wall:
> Hello!
> 
> On Thursday 30 July 2009 17:25:15 P Kishor wrote:
> > > I haven't looked at your work in depth, but I am interested in this. I
> > > have implemented a very simple versioning system with TRIGGERs whereby
> > > every change (INSERT, UPDATE, DELETE) in a column in a table is stored
> > > in a versions table along with its primary key, allowing me to go back
> > > and examine any version and roll back to it, if desired.
> 
> Yes, the primary key field is good enough for master-slave replication
> but not for multi-master because each master has self sequence counter.

  You're saying primary key when I think you more specifically mean
  ROWID.  Assuming you could override and force AUTOINCREMENT behavior
  on all tables (that might make an interesting PRAGMA), this could
  help with that:

  http://www.sqlite.org/cvstrac/tktview?tn=3563

  As long as the "BY" is greater than the number of masters and each
  master has a "FROM" that is sequenced, they'll leap-frog over each
  other.

  Then again, given that ROWID values are signed 64 bit values, you
  could just start each master at some offset (like +0x00FFFFFFFFFFFFFF)
  and not worry about it.  It would still be a good idea to force all
  the tables into an AUTOINCREMENT mode somehow.

  PRAGMA request: http://www.sqlite.org/cvstrac/tktview?tn=4002

   -j

-- 
Jay A. Kreibich < J A Y  @  K R E I B I.C H >

"Our opponent is an alien starship packed with atomic bombs.  We have
 a protractor."   "I'll go home and see if I can scrounge up a ruler
 and a piece of string."  --from Anathem by Neal Stephenson
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