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Use

The SAP liveCache data is organized in classes. Each class can consist of different containers. The OMS objects in a class can be distributed across multiple containers. Each container can consist of multiple page chains. Each OMS object has a unique object ID (OID) with which, for example, an application can request the object.

In the Performance user menu, you can find, among other things, a display of information about class containers since the last start of the liveCache Monitoring.

Prerequisites

The user has been assigned a role in accordance with the authorization concept. You can reach the user menu of the user with the authorizations that correspond to his or her role.

Procedure

  1. In the user menu, choose liveCache Assistant (transaction LC10).

  2. Enter the name of the database connection. You can select the name from the list of existing names. You can restrict the search for the required name.

  3. Choose Start of the navigation path liveCache Next navigation step Monitoring End of the navigation path.

  4. Choose Start of the navigation path Problem Analysis Next navigation step Performance Next navigation step Class Containers End of the navigation path.

The display is part of the DBA Cockpit and can therefore also be called as follows:

  1. Open DBA Cockpit (transaction DBACOCKPIT).

  2. The display options in DBA Cockpit vary depending on which SAP NetWeaver release you are using.

    • Choose Start of the navigation path Diagnosis Next navigation step Database Objects Next navigation step OMS Class Containers End of the navigation path.

    • SAP NetWeaver 7.1: Choose Start of the navigation path Performance Next navigation step Class Containers End of the navigation path.

You can select the displays as follows:

  • Selection of class containers (restriction by entering class name, schema name and/or container number. You do not need to enter the complete name or number. You can enter ranges, such as S* or similar)

  • All class containers (do not specify restriction)

Result

The system displays information about class containers. Every class container contains OMS objects for exactly one persistent class. The system displays information from the OMS intermediate layer and the SAP liveCache basis layer.

OMS Intermediate Layer

The OMS (Object Management System) intermediate layer manages the data (that is, the OMS objects) that are held in the application-specific OMS heap. The application always accesses its OMS data through the OMS intermediate layer and not directly with the SAP liveCache basis layer. If the data is not in the OMS intermediate layer, it is implicitly loaded from the data cache into the OMS intermediate layer. The system displays, among other things, the following analysis data which provides information about the OMS intermediate layer:

Class ID, Class Name, Schema, Container Number

SAP liveCache Basis Layer

The OMS objects are managed in the SAP liveCache basis layer. The data itself is located in the data cache and in the data area. The application cannot access this data directly; it can access the data only if it is in the OMS intermediate layer. The system displays, among other things, the following analysis data which provides information about the SAP liveCache basis layer:

Object Size, Container Size, Free Container Pages, Empty Container Pages, Key Pages, Container Usage, Number of Objects, Wastage, Key Inversions, File ID

You will find more detailed information on the OMS objects in the OMS Object Browser.

Calculation Formulas

  • Number of objects: <Container size>*8100*(<Ø Container usage>/100)/(<Object size>+24)

  • Net size of the liveCache (in KB): SELECT SUM (<Container size>*<Ø Container usage>/100)*8

More Information

liveCache Assistant, Class Container Sizes

DBA Cockpit: SAP MaxDB, OMS Class Containers, OMS Class Container Sizes