Cache hit ratio

PostgreSQL:

SELECT 
  sum(heap_blks_read) as heap_read,
  sum(heap_blks_hit)  as heap_hit,
  sum(heap_blks_hit) / (sum(heap_blks_hit) + sum(heap_blks_read)) as ratio
FROM 
  pg_statio_user_tables;

See also

• Databases: Database management, SQL, NoSQL, Wide column, PostgreSQL, MariaDB, MySQL, Derby DB, MongoDB, Cassandra, SQLite, HSQL2, H2, RocksDB, Microsoft SQL Server, DB2, Oracle Database, Memcached, Berkeley DB, Collation, SingleStore, Amazon Aurora, Graph database, Amazon DynamoDB, PrestoDB, Cache hit ratio, ACID, WAL, ARIES, DBMS, OLTP, OLAP, Database Schema, CockroachDB, Tables, Views, Apache Druid, RDMS