> On Wed, Apr 5, 2017 at 6:40 AM, Johann Spies <johann.sp...@gmail.com> wrote: >> >> On 4 April 2017 at 14:07, Johann Spies <johann.sp...@gmail.com> wrote: >> >> > Why would that be? >> >> To answer my own question. After experimenting a lot we found that >> 9.6 uses a parallel seqscan that is actually a lot faster than using >> the index on these large tables.
Further experimenting resulted in a solution which we do not understand: The table 'publication' had the field 'ut' as primary key and the ut index was not used. So we built an additional btree index(ut) on publication - which was ignored as well. Then we built a gin index(ut) on publication and now it is being used. The same happened on the other table (belongs_to) where the btree index was ignored by the planner but the gin-index used. As a result our deletes runs between 25-60 times faster than earlier with maximum of about 200000 records per hour in comparison with a maximum of 4500 earlier.. In the case of both tables the ut has a foreign key reference to another article. Why would the planner prefer the use the gin index and not the btree index in this case? Regards Johann -- Because experiencing your loyal love is better than life itself, my lips will praise you. (Psalm 63:3) -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
