How many tables do you have in your query? If too many, in your case “Genetic Query Optiomiation” might be used (https://www.postgresql.org/docs/10/geqo-pg-intro.html <https://www.postgresql.org/docs/10/geqo-pg-intro.html>).
> On 26. Nov 2019, at 03:19, Игорь Выскорко <vyskorko.i...@yandex.ru> wrote: > > Hi all! > I'm confused by planner choice: seqscan but not index scan when index scan > cost is much cheaper. > 1st plan: https://explain.depesz.com/s/Cti#l8 > 2nd plan (with "set enable_seqscan = off"): > https://explain.depesz.com/s/qn0I#l8 > > Look at 8th row: this nested loop decided to join the second node by using > seqscan (1st plan) when index is available (2nd plan). Index scan is much > cheaper (0.430 over 257.760). > > What am I missing? > > And thanks for any reply! > >
