How To Fix BRAIN014 - The query & now reads on demand when navigating

BRAIN014 - Overview

• Message type: E = Error

• Message class: BRAIN -

• Message number: 014

• Message text: The query & now reads on demand when navigating

The read mode determines how the OLAP processor retrieves data during
navigation. There are three different data-retrieval methods:
<ZH>Reading Data During Navigation / When Expanding Hierarchies</>
This mode transfers the smallest amount of data from the database to
the OLAP processor. However, it is also the mode that has the most
read-cycles.
In the "Read During Navigation" mode described below, the system
requests the data for the fully expanded hierarchy. In the "Read During
Navigation / Hierarchy Expansion" mode, however, the database
aggregates the data along the hierarchy and transfers it to the OLAP
processor at the lowest level of the hierarchy that is displayed in the
start list. When a hierarchy node is expanded, the system is able to
target the lower-level nodes directly.
You can improve the performance of queries that have large display
hierarchies, by creating aggregates on an intermediate level of the
hierarchy, greater than or equal to the start level.
<ZH>Reading Data During Navigation</>
Depending on the navigation status of the query in the Business
Explorer, the OLAP processor requests only the data that is required.
The data is read in each step of the navigation.
Unlike the "Read During Navigation / Hierarchy Expansion" mode, display
hierarchies are always read completely on the leaf-level.
When nodes are expanded, the OLAP processor is able to read the data
from the main memory.
When the database is accessed, the best aggregate tables are always
used and aggregated directly on the database whenever possible.
<ZH>Reading All the Data at Once</>
In this mode, there is only one actual read. However, when the query is
executed in the Business Explorer, all the data that is required for
all the possible navigation steps in the query is read from the main
memory of the OLAP processor. During navigation, any new navigation
statuses are aggregated and calculated from the data in the main
memory.
In general, the "Read During Navigation / Hierarchy Expansion" mode
performs better than the other two modes. This is because it requests
only the data that the user wants to see.
Unlike the "Read During Navigation / Hierarchy Expansion" mode, and
with regards to performance, the "Read During Navigation" setting
applies only to queries with display hierarchies.
With regards to performance, and in contrast to the other two modes,
the "Read All Data at Once" setting also applies to queries with free
characteristics. Since the OLAP processor transfers the aggregation for
each query view, the aggregate concept (working with pre-aggregated
data) is least supported in the "Read All Data at Once" mode.
<ZH>We recommend that you use the "Read During Navigation / Hierarchy
Expansion" mode.</>
Use a mode other than "Read During Navigation / Hierarchy Expansion"
only in exceptional cases.
The "Read All Data at Once" mode, for example, is useful in the
following cases:
The InfoProvider does not support selections, meaning that the OLAP
processor reads more data than is needed.
A user-exit is active in a query, and this prevents the system from
aggregating data on the database.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message BRAIN014 - The query & now reads on demand when navigating ?

  The SAP error message BRAIN014 indicates that a query is being executed in "on-demand" mode. This typically occurs in SAP BW (Business Warehouse) when a query is not fully optimized for performance or when certain settings are not configured correctly. Here’s a breakdown of the cause, potential solutions, and related information:
  
  Cause:
  
  Query Design: The query may be designed in a way that requires real-time data retrieval rather than using pre-aggregated data from the InfoCube or DataStore Object (DSO).
  Data Source Configuration: The data source may not be set up to allow for optimized data retrieval, leading to on-demand execution.
  Query Execution Settings: The settings in the query properties may not be configured to use cached data or pre-aggregated data.
  Performance Issues: If the system is experiencing performance issues, it may default to on-demand mode to ensure that the query can still run, albeit slower.
  
  Solutions:
  
  
  Optimize Query Design:
  
  Review the query structure and ensure that it is