Tab Page: Memory Settings

FLATFACTOR

Default value (20%) for size relation

The system compares the size (the number of rows) in the fact tables with the size of the dimension or SID tables (for items). If the size relation exceeds the limit, the system creates a partition attribute. This ensures that the JOIN can be executed locally with a good level of performance. If two tables in the fact table comparison exceed the limit, the system denormalizes the fact dimension scheme and creates a wide fact index in the BWA instead. This is known as a "flat" fact index.

20

DONT_IGNORE_BIA_OVERLOAD

Do not ignore the "BWA overload" message

If too much data is loaded into the BWA or the user load is so high that the temporary memory usage is too large, the stability of the BWA server can be impaired, and queries can crash.

To ensure early detection of high BWA loads, the system checks the current load of the BWA server during each process that increases the amount of data in the BWA. Processes that significantly increase the BWA load are rebuilding a BWA index and rolling up requests to the BWA. This BWA load check is also performed every time the BWA Monitor is called.

The system checks the following key figures:

• The ratio of memory usage by the loaded data to available main memory (see parameter USED_TO_TOTAL_MEM_RELATION).

• The number of main memory unloads in the past 24 hours (see parameter ALLOWED_UNLOADS_COUNT).

  As soon as one of the key figures exceeds the defined limit, a warning is written to the process log. The process (or the process application log in the process chain) then has the status "yellow".

  If you want the system to write an error to the process log instead, and to cancel the process, set parameter DONT_IGNORE_BIA_OVERLOAD (value = 'X').

USED_TO_TOTAL_MEM_RELATION

Limit for "Used/available main memory"

This parameter is evaluated when the BWA load is checked (see parameter DONT_IGNORE_BIA_OVERLOAD).

The index data on the filter should not exceed 50% of the available main memory. This is the recommended default value, but you can of course set other values.

0.5

ALLOWED_UNLOADS_COUNT

Limit for "Number of main memory displacements"

This parameter is evaluated when the BWA load is checked (see parameter DONT_IGNORE_BIA_OVERLOAD).

If bottlenecks occur due to high memory load, memory is displaced automatically in the BWA server. This can have an adverse effect on performance and stability.

The default setting for this limit is two unloads every 24 hours. This is the recommended default value, but you can of course set other values.

2