Hi I have this system with some databases and I have run the cache_hit_ratio.sql script on it. It showed that the db acme777booking had a ratio on 85%. I then changed shared_buffer size from 0.5GB to 4GB as the server has 16GB of physical RAM. After 6 days of running I checked the ratio again and it is still 85%. Am I doing something wrong or should some history be cleared?
cache_hit_ratio.sql datname | blks_read | blks_hit | cachehitratio ----------------+------------+--------------+--------------- acme777web | 50225009 | 3157586919 | 98.43 acmelog | 462198 | 14332508 | 96.88 acme777domain | 7540616252 | 119574349075 | 94.07 acme777booking | 337915568 | 1902310783 | 84.92 (4 rows) pg_runtime.sql pg_start | runtime -------------------------------+------------------------ 2018-07-12 06:49:48.654252+02 | 6 days 02:44:09.488978 (1 row) get_version_num.sql Version text | Num --------------+------- 9.1.9 | 90109 (1 row) SELECT pg_stat_database.datname, pg_stat_database.blks_read, pg_stat_database.blks_hit, round((pg_stat_database.blks_hit::double precision / (pg_stat_database.blks_read + pg_stat_database.blks_hit +1)::double precision * 100::double precision)::numeric, 2) AS cachehitratio FROM pg_stat_database WHERE pg_stat_database.datname !~ '^(template(0|1)|postgres)$'::text ORDER BY round((pg_stat_database.blks_hit::double precision / (pg_stat_database.blks_read + pg_stat_database.blks_hit + 1)::double precision * 100::double precision)::numeric, 2) DESC; OS: Red Hat Enterprise Linux Server release 6.4 (Santiago)