Re: How to improve the performance of my SQL query？

Thank you for your suggestion.
The database is hosted on AWS RDS, with the instance having vCPU=2 and RAM=4GB.
Could the low performance be due to the low configuration of AWS RDS?
We are considering trying a higher configuration instance.

At 2023-07-27 11:36:20, "David Rowley" <dgrowleyml(at)gmail(dot)com> wrote:
>On Wed, 26 Jul 2023 at 19:46, gzh <gzhcoder(at)126(dot)com> wrote:
>> QUERY PLAN (enable_seqscan=on)
>
>> Execution Time: 167183.133 ms
>
>> QUERY PLAN (enable_seqscan=off)
>
>> Execution Time: 22320.153 ms
>
>effective_cache_size and random_page_cost are the settings you should
>be adjusting to coax the planner into using the index.
>
>A rule of thumb for effective_cache_size would be to set it to about
>75% of RAM. There are certainly cases where lower would make more
>sense, certainly, 75% will make more sense than the default 4GB value
>in the majority of cases.
>
>For random_page_cost, the default of 4.0 has been the default since
>HDDs were common. SSDs are common now and, comparatively to sequential
>I/O, their random I/O is faster than that of an HDD, so you may get
>better results by lowering random_page_cost.
>
>David