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title DBA SGA Buffer Cache Object Usage | Oracle EBS SQL Report
description SGA buffer cache space usage by object names (in MB). 'Object Percentage' shows how much of one particular object is currently stored in the buffer cache…
keywords Oracle EBS, Oracle E-Business Suite, SQL report, Blitz Report, Enginatics, DBA, SGA, Buffer, Cache, gv$bh
permalink /DBA%20SGA%20Buffer%20Cache%20Object%20Usage/

DBA SGA Buffer Cache Object Usage – Oracle EBS SQL Report

Oracle E-Business Suite SQL report from the Enginatics Library powered by Blitz Report™.

Overview

SGA buffer cache space usage by object names (in MB). 'Object Percentage' shows how much of one particular object is currently stored in the buffer cache. 100% means that the object is completely in the buffer cache.

Current SGA memory usage is also listed in views: select * from v$sga select * from v$sgainfo select * from v$sga_dynamic_components

Arup Nanda gives a good explanation on how the buffer cache works: http://arup.blogspot.ch/2014/11/cache-buffer-chains-demystified.html

Report Parameters

Show Block Status

Oracle EBS Tables Used

gv$bh

Report Categories

Enginatics

Related Reports

DBA SGA+PGA Memory Configuration, FND Concurrent Requests 11i, DBA Result Cache Statistics

Running This SQL Without Blitz Report

Some Oracle EBS SQL reports in this library require functions from the utility package xxen_util. Install it before running the SQL directly against your Oracle EBS database.

Download & Import Options

Resource Link
Excel Example Output DBA SGA Buffer Cache Object Usage 05-Apr-2020 014325.xlsx
Blitz Report™ XML Import DBA_SGA_Buffer_Cache_Object_Usage.xml
Full SQL on Enginatics www.enginatics.com/reports/dba-sga-buffer-cache-object-usage/

Case Study & Technical Analysis

Abstract

The DBA SGA Buffer Cache Object Usage report provides a detailed breakdown of how the Database Buffer Cache memory is being utilized. It identifies which database objects (tables, indexes, clusters) are currently resident in RAM. This insight is critical for verifying that the most frequently accessed data is being cached effectively and for identifying "cache pollution" where large, infrequently used segments are washing out critical data.

Technical Analysis

Core Metrics

  • Size (MB): The amount of buffer cache memory occupied by a specific object.
  • Object Percentage: The percentage of the object's total size that is currently cached. A value of 100% means the entire table/index is in memory.
  • Block Status: (Optional) Can differentiate between xcur (exclusive current), scur (shared current), and cr (consistent read) blocks, which is useful for RAC cache fusion analysis.

Key View

  • GV$BH: The Buffer Header view. This is a high-volume view that lists every single block currently in the buffer cache. Querying this on a busy, large-SGA system can be expensive, so use with caution.

Operational Use Cases

  • Sizing Verification: Determining if DB_CACHE_SIZE is adequate for the working set.
  • Pinning Candidates: Identifying small, hot tables that are frequently re-read and might benefit from being pinned (though less common in modern Oracle versions).
  • Performance Tuning: Detecting if a full table scan on a massive log table has flushed useful indexes out of the cache.
  • RAC Analysis: Understanding block distribution across instances in a cluster.

Useful Links

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