On Thu, 10 Dec 2020 at 19:37, David G. Johnston <david.g.johns...@gmail.com> wrote:
> On Wed, Dec 9, 2020 at 1:31 PM electrotype <electrot...@gmail.com> wrote: > >> Agreed. >> >> >> However, this isn't really the purview of JDBC - I'm doubting it does >> anything that would cause the order to be different than what is received, >> and the batch items are sent and results processed sequentially. >> >> The main question is whether any batch items are inserting multiple >> records themselves - i.e., RETURNING * is producing multiple results. >> Whatever order RETURNING * produces is what the driver will capture - but >> it isn't responsible for guaranteeing that the order of multiple inserted >> records going in matches what comes out. PostgreSQL needs to make that >> claim. I don't see where it does (i've sent an email to see if adding such >> a claim to the documentation is proper). Done manually one can always do >> "WITH insert returning SELECT ORDER BY", but it doesn't seem workable for >> the driver to try and do that when adding the returning clause, which I >> presume is what is in scope here. >> >> David J. >> >> Thank you, it's appreciated! I'm sure this clarification would help other >> developers too. >> > > My take is that there is presently no guarantee, and that with current > efforts to add parallelism it is quite probable that observation of such > non-orderedness is simply a matter of time. With batching it seems best to > combine its use with single inserts in order to avoid this problem. > > David J. > I'd have to agree. Dave Cramer www.postgres.rocks
