On Wed, 26 Jul 2023 at 19:46, gzh <gzhcoder@xxxxxxx> 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
