On Thu, Sep 15, 2016 at 10:44 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> On Thu, Sep 15, 2016 at 9:59 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>> Possibly we ought to change things so that the default value of >>> min_parallel_relation_size is a fixed number of bytes rather >>> than a fixed number of blocks. Not sure though. > >> The reason why this was originally reckoned in blocks is because the >> data is divided between the workers on the basis of a block number. >> In the degenerate case where blocks < workers, the extra workers will >> get no blocks at all, and thus no rows at all. > > Well, sure, but at any reasonable value of min_parallel_relation_size > that won't be a factor. The question here is whether we want the default > value to be platform-independent. I notice that both config.sgml and > postgresql.conf.sample claim that the default value is 8MB, which this > discussion reveals to be a lie. If you want to keep the default expressed > as "1024" and not "(8 * 1024 * 1024) / BLCKSZ", we need to change the > documentation.
I don't particularly care about that. Changing it to 8MB always would be fine with me. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers