How To Fix BRAIN015 - Query & now reads all the data at once

SAP Error Message - Details

• Message type: E = Error

• Message class: BRAIN -

• Message number: 015

• Message text: Query & now reads all the data at once

What causes this issue?

When executing the query in the Business Explorer<(>,<)> all of the fact
table data that is needed for all possible navigational steps in the
query is read in the main memory area of the OLAP processor at once.
This can sometimes lead to very long run times in the query.
For a query, the OLAP processor can read the data in the fact table in
one of three ways:
Reading all of the data
When executing the query in the Business Explorer all of the fact table
data, that is needed for all possible navigational steps in the query,
is read in the main memory area of the OLAP processor. Therefore, all
new navigational states are aggregated and calculated from the data of
the main memory.
Reading the data on demand:
The OLAP processor only requests the corresponding fact table data that
is needed for each navigational state of the query in the Business
Explorer. Therefore, new data is read for each navigational step. The
most suitable aggregate table is used and, if possible, already
aggregated on the database. The data for identical navigational states
yavigating is buffered in the OLAP processor.
Reading on demand when expanding the hierarchy:
When reading data on demand (2), the data for the entire - meaning
completely expanded - hierarchy is requested for a hierarchy drilldown.
For the read on demand when expanding the hierarchy (3), the data is
aggregated by the database along the hierarchy and is sent to the start
level of the hierarchy (highest node) in the OLAP processor. When
expanding a hierarchy node, the children of the node are then
respectively read on demand.

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

In general, the reading of data on demand (2) provides much better
performance than reading all the data (1). This read mode should
especially be considered for queries with many, free characteristics. A
query that contains two or more free characteristics from different
dimensions (e.g. 'Customer' and 'Product'), will probably only be
efficiently executable in this mode, as the aggregates can only be
optimally used when reading the data on demand.
For large hierarchies, aggregates should be created a middle level of
the hierarchy and the start level of the query should be smaller or the
same as this aggregate level. For queries about such large hierarchies,
the read on demand when expanding the hierarchy method (3) should be
set.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message BRAIN015 - Query & now reads all the data at once ?

  The SAP error message BRAIN015 typically indicates an issue related to the performance of queries in SAP BW (Business Warehouse) or SAP BI (Business Intelligence). The message suggests that the query is attempting to read all the data at once, which can lead to performance degradation, especially with large datasets.
  Cause:
  
  Query Design: The query may be designed in a way that it retrieves all records without any filters or aggregations, leading to excessive data being processed at once.
  Data Volume: The underlying data volume is too large, and the query is not optimized to handle such a volume efficiently.
  Missing Aggregates: If aggregates are not defined or used in the query, it may lead to reading all the detailed data instead of summarized data.
  Performance Settings: The settings in the query or the InfoProvider may not be optimized for performance, leading to inefficient data retrieval.
  
  Solution:
  
  
  Optimize Query Design:
  
  Review the query design and ensure that appropriate filters are applied to limit the data being retrieved.
  Use variables to prompt users for input, which can help in narrowing down the data set.
  Consider using calculated key figures or restricted key figures to reduce the amount of data processed.
  
  
  
  Use Aggregates:
  
  Create and utilize aggregates in the InfoCube to allow the query to read summarized data instead of detailed data.
  Ensure that the aggregates are up-to-date and relevant to the queries being run.
  
  
  
  Performance Tuning:
  
  Check the performance settings in the query properties and adjust them as necessary.
  Analyze the execution plan of the query to identify bottlenecks and optimize accordingly.
  
  
  
  Data Modeling:
  
  Review the data model to ensure that it is designed for optimal performance. This may involve restructuring InfoProviders or using different types of InfoProviders (e.g., using CompositeProviders).
  
  
  
  Monitoring and Analysis:
  
  Use transaction codes like RSRT (Query Monitor) to analyze the performance of the query and identify areas for improvement.
  Monitor the system performance during query execution to identify any resource bottlenecks.
  
  
  
  Related Information:
  
  SAP Notes: Check for any relevant SAP Notes that may address specific issues related to the BRAIN015 error or performance tuning in BW/BI.
  Documentation: Refer to SAP BW/BI documentation for best practices in query design and performance optimization.
  Community Forums: Engage with SAP community forums or user groups to share experiences and solutions related to similar issues.
  
  By addressing the underlying causes and implementing the suggested solutions, you should be able to resolve the BRAIN015 error and improve the performance of your SAP queries.