On Thu, Jun 21, 2018 at 07:42:54AM +0530, Amit Kapila wrote: > On Wed, Jun 20, 2018 at 8:47 PM, Bruce Momjian <br...@momjian.us> wrote: > > On Sat, Jun 2, 2018 at 05:18:17PM -0400, Asim Praveen wrote: > >> Hi Amit > >> > >> On Mon, May 28, 2018 at 4:25 AM, Amit Kapila <amit.kapil...@gmail.com> > >> wrote: > >> > > >> > This is one way, but I think there are other choices as well. We can > >> > identify and flush all the dirty (local) buffers for the relation > >> > being accessed parallelly. Now, once the parallel operation is > >> > started, we won't allow performing any write operation on them. It > >> > >> We talked about this in person in Ottawa and it was great meeting you! > >> To summarize, the above proposal to continue using local buffers for > >> temp tables is a step forward, however, it enables only certain kinds > >> of queries to be parallelized for temp tables. E.g. queries changing > >> a temp table in any way cannot be parallelized due to the restriction > >> of no writes during parallel operation. > > > > Should this be a TODO item? > > > > +1. I think we have not hammered out the design completely, but if > somebody is willing to put effort, it is not an unsolvable problem. > AFAIU, this thread is about parallelizing queries that refer temp > tables, however, it is not clear from the title of this thread.
Seems it is already documented on the wiki: https://wiki.postgresql.org/wiki/Parallel_Query#What_Parts_of_a_Query_Can_Run_In_Parallel.3F o Scans of plain tables may not appear below Gather if (1) they are temporary tables ... ---------------- -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription +