On Tue, Dec 8, 2015 at 9:10 PM, Robert Haas <robertmh...@gmail.com> wrote: > > On Mon, Nov 30, 2015 at 7:47 AM, Kyotaro HORIGUCHI > <horiguchi.kyot...@lab.ntt.co.jp> wrote: > > But is it important enough to be worthwhile? Maybe, maybe not. I > think we should be working toward a world where the Gather is at the > top of the plan tree as often as possible, in which case > asynchronously kicking off a Gather node won't be that exciting any > more - see notes on the "parallelism + sorting" thread where I talk > about primitives that would allow massively parallel merge joins, > rather than 2 or 3 way parallel. From my point of view, the case > where we really need some kind of asynchronous execution solution is a > ForeignScan, and in particular a ForeignScan which is the child of an > Append. In that case it's obviously really useful to be able to kick > off all the foreign scans and then return a tuple from whichever one > coughs it up first. >
How will this be better than doing the same thing in a way we have done Parallel Sequential Scan at ExecutorRun() time? With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
