2026-03-12 20:23:15

idev/perf_lru_latch_contention.sql

@@ -0,0 +1,34 @@
+-- +----------------------------------------------------------------------------+
+-- |                          Jeffrey M. Hunter                                 |
+-- |                      jhunter@idevelopment.info                             |
+-- |                         www.idevelopment.info                              |
+-- |----------------------------------------------------------------------------|
+-- |      Copyright (c) 1998-2011 Jeffrey M. Hunter. All rights reserved.       |
+-- |----------------------------------------------------------------------------|
+-- | DATABASE : Oracle                                                          |
+-- | FILE     : perf_lru_latch_contention.sql                                   |
+-- | CLASS    : Tuning                                                          |
+-- | PURPOSE  : This script will detect latch contention in the db block buffer |
+-- |            LRU. The ratio of sleeps/gets should be < 1%.                   |
+-- | NOTE     : As with any code, ensure to test this script in a development   |
+-- |            environment before attempting to run it in production.          |
+-- +----------------------------------------------------------------------------+
+
+SET LINESIZE 145
+SET PAGESIZE 9999
+SET VERIFY   off
+
+COLUMN child_num           HEADING "Child Number"
+COLUMN ratio_sleeps_gets   HEADING "Sleeps / Gets Ratio"
+COLUMN ratio               HEADING "Ratio"
+
+SELECT
+    child#                             child_num
+  , ROUND(sleeps/gets * 100,2)         ratio_sleeps_gets
+  , ROUND(((1 - sleeps/gets) * 100),2) ratio
+FROM
+  v$latch_children
+WHERE
+  name = 'cache buffers lru chain'
+/ 
+