I see you are comparing 9.2 and 9.4 -- if you were not already aware there is a kernel restriction on shared memory on Linux systems which, if I recall correctly, must be adjusted in versions before 9.3... https://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server#shared_buffers Not saying it's the answer but maybe another thing to look at... All the best Peter -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general