DB01922W - BEST PRACTICE SUGGESTION - recommendations
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DB01922W - BEST PRACTICE SUGGESTION - recommendations

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Article ID: 238551

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Updated On:

Products

Datacom/DB Datacom Datacom/AD

Issue/Introduction

During the Datacom MUF startup various DB01922W - BEST PRACTICE SUGGESTION messages are issued.

 DB01922W - BEST PRACTICE SUGGESTION - 6) DATAPOOL DATA2 LT 1000, TARGET 1K-20K
 DB01922W - BEST PRACTICE SUGGESTION - 9) FLEXPOOL NE 0, TARGET 0
 DB01922W - BEST PRACTICE SUGGESTION - 24) HISTORY MISSING
 DB01922W - BEST PRACTICE SUGGESTION - 25) LOGRCV SET AS YES/NEVER

What needs to be changed? What are the recommendations and how to test?

These are the current values for these options:

DB01900I - DATAPOOL   4K,6K,32767,300     DATA BUFFER SIZE,# OF BUFFERS,
DB01900I - *                              LARGE DATA BFR SIZE,# LARGE BUFFERS
DB01900I - FLEXPOOL   100,100,100,100     BUFFERS FOR IXX, DXX, DATA, LARGE DAT
DB01900I - LOGRCV     NEVER               LOG RECOVERY FILE AVAILABLE

Environment

z/OS

 

Cause

The best practices are suggestions to make option changes to what is considered best practice for best performance.  Read about the Best Practice messages in documentation section New MUF SYSPRINT Messages for Best Practices

The best practice message is described in the documentation for message DB01922W.

Resolution

The messages are just suggestions so you don't need to make the changes. The system will still work with the current startup options.

If you decide not to make a change, individual best practice suggestions can be turned off with the MUF startup parameter BEST_PRACTICES_OFF nn.
Where nn is the best practice number from message DB01922W. See Article 1152 for more details.

The first 2 suggestions are to make the MUF perform better so you can't really test unless you keep statistics before and after the change. There is a discussion of database buffers in section Optimizing Datacom/DB Performance

 DB01922W - BEST PRACTICE SUGGESTION - 6) DATAPOOL DATA2 LT 1000, TARGET 1K-20K'

The DATA2 number of buffers is recommended to be at least 1000, so change the DATAPOOL statement to:

DATAPOOL   4K,6K,32767,1000     DATA BUFFER SIZE,# OF BUFFERS,

 DB01922W - BEST PRACTICE SUGGESTION - 9) FLEXPOOL NE 0, TARGET 0

It's not recommended to have FLEXPOOL buffers defined at startup so remove the following:

FLEXPOOL   100,100,100,100     BUFFERS FOR IXX, DXX, DATA, LARGE DAT

DB01922W - BEST PRACTICE SUGGESTION - 25) LOGRCV SET AS YES/NEVER

The following statement indicates no recover file is available so no forward or backward recovery is possible:

LOGRCV     NEVER               LOG RECOVERY FILE AVAILABLE

Is this a production system, or even a test system you would want to have recovery available.
To enable recovery change the LOGRCV option to specify an inactive Recovery File:

LOGRCV     NO

 DB01922W - BEST PRACTICE SUGGESTION - 24) HISTORY MISSING

This history database stores historic information on the Datacom MUF. See documentation of this in section Creating and Maintaining the History Database

You enable it by specifying the HISTORY statement plus some others.

HISTORY    1007                HISTORY DATABASE DBID
HISTORY_END_HOUR   00          00-24 HOUR TO COLLECT HISTORY  
HISTORY_EVENT_TABLE  YES    SUPPORT FOR EVT

Additional Information

Also see Article 201601 - Dealing with DB01922W BEST PRACTICES messages with the ENF IMUF