Yep. Unclear. What parameter is recommended for SSD? Lower? 3? 2? 1? Much better will be write: if you use SSD set 1.
Олег > 19 марта 2020 г., в 23:56, Bruce Momjian <br...@momjian.us> написал(а): > > On Thu, Feb 27, 2020 at 02:48:44PM +0000, PG Doc comments form wrote: >> The following documentation comment has been logged on the website: >> >> Page: https://www.postgresql.org/docs/12/runtime-config-query.html >> Description: >> >> Explanation for random_page_cost is rather outdated, because it did only for >> case of mechanical hdd. But all modern database servers, which I know, made >> upon SSD. Do or not do default value for random_page_cost equal to 1 is the >> question, but, IMHO, at list in the documentation about random_page_cost >> need to add in a speculation about SSD. >> >> It's important because a business programming now is mostly web programming. >> Most database is poorly designed by web programmer, tables looked like a >> primary key and a huge json (containing all) with large gin index upon it. >> Now I am seeing a table with a GIN index 50% of the table size. The database >> is on SSD, of cause. With default random_page_cost=4 GIN index don't used >> by planner, but with random_page_cost=1 the result may be not excellent, but >> acceptable for web programmers. > > Does this sentence in the random_page_cost docs unclear or not have enough > visibility: > > > https://www.postgresql.org/docs/12/runtime-config-query.html#RUNTIME-CONFIG-QUERY-CONSTANTS > > Storage that has a low random read cost relative to sequential, e.g. > solid-state drives, might also be better modeled with a lower value for > random_page_cost. > > -- > Bruce Momjian <br...@momjian.us> https://momjian.us > EnterpriseDB https://enterprisedb.com > > + As you are, so once was I. As I am, so you will be. + > + Ancient Roman grave inscription +
