ITAGAKI Takahiro <itagaki.takahiro@oss.ntt.co.jp> writes:
> There might be regularity in the plan selection. When I connect to postgres
> newly, I see plans { A, B, A, A ... }. Then disconnect, re-connect and send
> the same EXPLAINs, the same pattern was reproduced.
Hmph ... maybe some effect associated with loading up the backend's
internal caches? I can't imagine what though.
Please see if you can extract a more self-contained test case.
regards, tom lane