Hello, As people may know, I've implemented a relation cache mechanism on top of custom-plan interface, that holds contents of a particular columns only, thus it does not need to take storage access as long as user's query refers the columns on in-memory cache. The key factor of how this mechanism works is selection of columns to be cached on the initial read, or re-read, of the related heap. The simplest idea is just picking up referenced columns in the query on demand, and will reconstruct later if further query referenced more wider reference than previous one, however, it is not a good strategy. So, I'd like to investigate the way to select columns to be cached adaptively. Probably, one better idea is columns-selection according to the frequency of column references in a particular time-slot. Right now, pg_statistic does not record such kind of information, if I can understand correctly. Is there any way to retrieve how many times columns were referenced? Or, do I need to implement an own extension to track it?
Thanks, -- KaiGai Kohei <kai...@kaigai.gr.jp> -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers