On 01/14/2014 06:12 PM, Robert Haas wrote: > This would be pretty similar to copy-on-write, except > without the copying. It would just be > forget-from-the-buffer-pool-on-write.
+1 A version of this could probably already be implement using MADV_DONTNEED and MADV_WILLNEED Thet is, just after reading the page in, use MADV_DONTNEED on it. When evicting a clean page, check that it is still in cache and if it is, then MADV_WILLNEED it. Another nice thing to do would be dynamically adjusting kernel dirty_background_ratio and other related knobs in real time based on how many buffers are dirty inside postgresql. Maybe in background writer. Question to LKM folks - will kernel react well to frequent changes to /proc/sys/vm/dirty_* ? How frequent can they be (every few second? every second? 100Hz ?) Cheers -- Hannu Krosing PostgreSQL Consultant Performance, Scalability and High Availability 2ndQuadrant Nordic OÜ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
