On Sat, Mar 4, 2017 at 2:01 PM, Peter Geoghegan <p...@bowt.ie> wrote: > On Sat, Mar 4, 2017 at 12:23 AM, Robert Haas <robertmh...@gmail.com> wrote: >>> I guess that the workMem scaling threshold thing could be >>> min_parallel_index_scan_size, rather than min_parallel_relation_size >>> (which we now call min_parallel_table_scan_size)? >> >> No, it should be based on min_parallel_table_scan_size, because that >> is the size of the parallel heap scan that will be done as input to >> the sort. > > I'm talking about the extra thing we do to prevent parallelism from > being used when per-worker workMem is excessively low. That has much > more to do with projected index size than current heap size.
Oh. But then I don't see why you need min_parallel_anything. That's just based on an estimate of the amount of data per worker vs. maintenance_work_mem, isn't it? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
