How To Fix HH054 - The 'read ahead' quality could be better (parameter RA_PAGES too big?)

SAP Error Message - Details

• Message type: E = Error

• Message class: HH - (Long) text for check tool 'infcfgcheck'

• Message number: 054

• Message text: The 'read ahead' quality could be better (parameter RA_PAGES too big?)

What causes this issue?

This is a single 'performance' check and therefore does not
describe a critical system status. It is neither necessary nor
time-critical to perform the steps described below, but they could
help improve the overall performance of your R/3 System.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

The quality of the Informix feature 'Read ahead' (percent ratio
between pages read as a preventive measure and pages actually used
in the database buffer) is not very good. The reason for this could
be that the ONCONFIG parameter 'RA_PAGES' is configured too large.
'RA-PAGES' specifies the number of pages to be read as a preventive
measure. If this value is constantly too large, the displacement
in the buffer will be too large. Only configure a 'realistic'
value for 'RA_PAGES'.
Also read Note 41360 (parameter 'RA_PAGES') about this topic.

System Response

How to fix this error?

To change an ONCONFIG parameter, edit file
'$INFORMIXDIR/etc/$ONCONFIG'. as user 'informix'.
CAUTION: The change will only become active after starting up the
database.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message HH054 - The 'read ahead' quality could be better (parameter RA_PAGES too big?) ?

  The SAP error message HH054, which states "The 'read ahead' quality could be better (parameter RA_PAGES too big?)", typically relates to the performance of the database and the way data is being read into memory. This message is often associated with the database's read-ahead mechanism, which is designed to pre-fetch data pages into memory to improve performance during data retrieval operations.
  Cause:
  
  RA_PAGES Parameter: The error suggests that the RA_PAGES parameter, which controls the number of pages that the database reads ahead, may be set too high. When this parameter is too large, it can lead to inefficiencies in memory usage and may not provide the expected performance benefits.
  Database Performance: The underlying database may be experiencing performance issues, such as high I/O wait times or insufficient memory, which can affect the effectiveness of the read-ahead mechanism.
  Data Access Patterns: If the application is accessing data in a way that does not align well with the read-ahead strategy (e.g., random access patterns), it can lead to suboptimal performance.
  
  Solution:
  
  Adjust RA_PAGES Parameter: Review and adjust the RA_PAGES parameter to a more appropriate value. This may involve reducing the number of pages to improve the quality of read-ahead operations. The optimal value can vary based on the specific workload and database configuration, so it may require some experimentation.
  Monitor Database Performance: Use database monitoring tools to analyze performance metrics. Look for high I/O wait times, memory usage, and other indicators that may suggest the need for further tuning.
  Optimize Queries: Review and optimize the SQL queries being executed. Ensure that they are efficient and make use of appropriate indexing to reduce the need for excessive read-ahead.
  Database Configuration: Consider other database configuration parameters that may impact performance, such as buffer pool size, cache settings, and I/O settings.
  Consult Documentation: Refer to the SAP and database documentation for specific recommendations on tuning parameters and improving read-ahead performance.
  
  Related Information:
  
  SAP Notes: Check for any relevant SAP Notes that may provide additional guidance or updates related to this error message.
  Database Documentation: Review the documentation for the specific database being used (e.g., SAP HANA, Oracle, SQL Server) for best practices on performance tuning and configuration.
  Performance Tuning Guides: Look for performance tuning guides specific to your SAP environment and database to gain insights into optimizing performance.
  
  By addressing the RA_PAGES parameter and monitoring overall database performance, you can improve the quality of the read-ahead mechanism and reduce the occurrence of this error message.