On Thu, Jun 11, 2009 at 12:59 PM, Brett Henderson<brett@xxxxxxxxxx> wrote: > Greg Stark wrote: >> Another option to consider would be including a boolean column >> "dumped" defaulted to false. Then you could have a partial index on >> the primary key or date "WHERE NOT dumped". Then when you dump you can >> "SELECT FOR UPDATE * WHERE NOT dumped" and then when you're done >> "UPDATE SET dumped = 't' ". Alternately you could use "UPDATE SET >> dumped='t' WHERE NOT dumped RETURNING *" which is basically >> equivalent. >> > > I have a couple of hesitations with using this approach: > 1. We can only run the replicator once. > 2. We can only run a single replicator. > 3. It requires write access to the db. 4. it requires a schema change to support this use case. again, this isn't a massive issue. but for the time being we're at least making an effort to not extend the schema beyond what the rails code itself requires. > 3 is also a major consideration, it makes everybody's life easier if we can > avoid updates being made to the db by the replicator. for safety's sake i think this makes a lot of sense. > I hope I don't sound too negative. My gut also tells me that what we're > doing is not the "right" solution and I've had fairly similar arguments with > Matt already :-) But having spent some time playing with it I can't find > any reason why it won't work, and from a performance point of view I suspect > it will win ... it seems right to me to use postgres' existing features to support this. we've got pretty close to a working system without needing schema changes, so it would be a shame if they turn out to be necessary. cheers, matt -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
