On Sun, Dec 9, 2018 at 6:24 AM Justin Pryzby <pry...@telsasoft.com> wrote: > > The docs say: > https://www.postgresql.org/docs/current/runtime-config-query.html > |min_parallel_table_scan_size Sets the minimum amount of table data that must > be scanned in order for a parallel scan to be considered. [...] > > I'd like to set parallel_min_table_size=32MB, but it looks like that won't do > what I intend for at least one of our tables using inheritence. > > It seems to me that an individual table should not be scanned in parallel if > its size is below the threshold, even if it's a child and has siblings which > are larger and scanned in parallel. > > I found that the current behavior seems to be more or less deliberate,
Yes, you are right. > but > maybe should be revisited following implementation of "parallel append" node, > as previously discussed. > Why? How does parallel append help for individual table/partition scan? If you want the parallel scan to be forced for any individual table, you might want to try setting 'parallel_workers' parameter for that table. For example 'Alter Table tbl Set (parallel_workers=2);' -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
