The behavior of Maximum Memory Per Request depends on the following Data Integration Service configurations:

The service runs jobs in separate local or remote processes, or the service property Maximum Memory Size is 0 (default).
In this case, Maximum Memory Per Request is the maximum amount of memory, in bytes, that the Data Integration Service can allocate to all transformations that use auto cache mode in a single request. The service allocates memory separately to transformations that have a specific cache size. The total memory used by the request can exceed the value of Maximum Memory Per Request.
The service runs jobs in the Data Integration Service process, and the service property Maximum Memory Size is greater than 0.
In this case, Maximum Memory Per Request is the maximum amount of memory, in bytes, that the Data Integration Service can allocate to a single request. The total memory used by the request cannot exceed the value of Maximum Memory Per Request.

Default is 536,870,912.

Maximum amount of memory, in bytes, that the Data Integration Service can allocate for running all requests concurrently when the service runs jobs in the Data Integration Service process. When the Data Integration Service runs jobs in separate local or remote processes, the service ignores this value. If you do not want to limit the amount of memory the Data Integration Service can allocate, set this property to 0.

If the value is greater than 0, the Data Integration Service uses the property to calculate the maximum total memory allowed for running all requests concurrently. The Data Integration Service calculates the maximum total memory as follows:

Maximum Memory Size + Maximum Heap Size + memory required for loading program components

Default is 0.

Amount of RAM allocated to the Java Virtual Machine (JVM) that runs the Data Integration Service. Use this property to increase the performance. Append one of the following letters to the value to specify the units:

b for bytes.
k for kilobytes.
m for megabytes.
g for gigabytes.

Default is 1024 megabytes.