2026-03-12 20:23:15

timhall/monitoring/db_cache_advice.sql

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+-- -----------------------------------------------------------------------------------
+-- File Name    : https://oracle-base.com/dba/monitoring/db_cache_advice.sql
+-- Author       : Tim Hall
+-- Description  : Predicts how changes to the buffer cache will affect physical reads.
+-- Requirements : Access to the V$ views.
+-- Call Syntax  : @db_cache_advice
+-- Last Modified: 12/02/2004
+-- -----------------------------------------------------------------------------------
+
+COLUMN size_for_estimate          FORMAT 999,999,999,999 heading 'Cache Size (MB)'
+COLUMN buffers_for_estimate       FORMAT 999,999,999 heading 'Buffers'
+COLUMN estd_physical_read_factor  FORMAT 999.90 heading 'Estd Phys|Read Factor'
+COLUMN estd_physical_reads        FORMAT 999,999,999,999 heading 'Estd Phys| Reads'
+
+SELECT size_for_estimate, 
+       buffers_for_estimate,
+       estd_physical_read_factor,
+       estd_physical_reads
+FROM   v$db_cache_advice
+WHERE  name          = 'DEFAULT'
+AND    block_size    = (SELECT value
+                        FROM   v$parameter
+                        WHERE  name = 'db_block_size')
+AND    advice_status = 'ON';