Hi Tom,
Thank you for your prompt response.
I've run analyze(not vacuum analyze), but it doesn't seem to work.
Is there any other way to optimize the database?
At 2022-10-10 00:02:09, "Tom Lane" <tgl@sss.pgh.pa.us> wrote:
>gzh <gzhcoder@126.com> writes:
>> I run following sql in PostgreSQL 8.4 and PostgreSQL 12.11, it returns different execution plan.
>
>Have you done an ANALYZE in the new database? The rowcount estimates
>seem a lot different, leading me to guess that the newer installation
>doesn't have good statistics yet.
>
> regards, tom lane