Re: Set enable_seqscan doesn't take effect?

2023年9月28日 12:26，David G. Johnston <david.g.johnston@gmail.com> 写道：

On Wednesday, September 27, 2023, jacktby jacktby <jacktby@gmail.com> wrote:

postgres=# SET enable_seqscan = off;
SET
postgres=# explain select * from t;
                               QUERY PLAN                               
-------------------------------------------------------------------------
 Seq Scan on t  (cost=10000000000.00..10000000023.60 rows=1360 width=32)

It wouldn’t cost 10billion to return the first tuple if that setting wasn’t working.

That is the “discouragement” the documentation is referring to.

I do agree the wording in the docs could be improved since it is a bit self-contradictory and unspecific, but it is explicitly clear a plan with sequential scan can still be chosen even with this set to off.

David J.