- Note
- Note that by this procedure you cannot estimate the memory size when using the functionality for reducing Explicit heap memory size utilized by an HTTP session. Follow the procedure described in 7.10.5 How to estimate using statistical information(1) for the memory size if you are using functionality for reducing Explicit heap memory size utilized by an HTTP session.
The memory size of the Explicit heap used by HTTP session-related objects is estimated with the following formula:
Memory-size-of-the-Explicit-heap-used-by-HTTP-session-related-objects
= Memory-size-of-the-Explicit-heap-used-in-the-HTTP-session + Memory-size-of-the-Explicit-heap-area-used-in-the-Web-container |
The memory size of the Explicit heap used by the HTTP session is estimated with the following formula:
Memory-size-of-the-Explicit-heap-used-in-the-HTTP-session
= Memory-size-used-in-one-session#1 Number-of-sessions-required-in-the-system |
The memory size of the Explicit heap area used in the Web container for the HTTP session is estimated with the following formula:
Memory-size-of-the-Explicit-heap-area-used-in-the-Web-container
= Size-of-the-objects-used-for-managing-the-HTTP-sessions#2 (Number-of-Web-applications#3 + 2) |
- #1
- Memory-size-used-in-one-session is equivalent to the size of one Explicit memory block. To estimate the size of one Explicit memory block, actually run the application and check the usage of the Explicit heap. Note that the minimum size of the Explicit memory block differs depending on the use of the automatic allocation functionality of the Explicit Memory Management functionality. The following table describes the minimum size of the Explicit memory block depending on the use of the automatic allocation functionality of the Explicit Memory Management functionality.
Table 7-5 Minimum size of the Explicit memory block depending on the use of the automatic allocation functionality of the Explicit Memory Management functionality
Item number | Whether the automatic allocation functionality of the Explicit Memory Management functionality is used | Minimum size of Explicit memory block |
---|
1 | Y | 16 kilobytes |
2 | -- | 64 kilobytes |
- Legend:
- Y: Automatic allocation functionality of the Explicit Memory Management functionality is used.
- --: Automatic allocation functionality of theExplicit Memory Management functionality is not used.
- You can extend the Explicit memory block in 64 kilobyte units. Therefore, the size would be "size-of-one-Explicit-memory-block
memory-size-used-in-one-session". Also, estimate the size by adding 16 kilobytes when using the automatic allocation functionality of theExplicit Memory Management functionality.
- #2
- Size-of-the-objects-used-for-managing-the-HTTP-sessions is the minimum size of the Explicit memory block described in Table 7-5.
- #3
- Number-of-Web-applications shows the number of running Web applications.
- Organization of this subsection
- (1) Estimation procedure
- (2) Estimation example
This point shows an estimation example based on the output example of event log of the explicit management heap functionality. An output example of the explicit management heap functionality is as follows:
- Output example of event log of explicit management heap functionality:
[ENS]Thu Oct 21 14:55:50 2007[EH: 12672K->12800K(12800K/65536K)][E/F/D: 200/0/0][cause:GC][CF: 0] |
In this example, the allocated size of Explicit heap is 12,800 Kilobytes, and the number of Explicit memory block is 200. If this value is applied according to step (5) of (1) Estimation procedure, it is displayed as follows:
- Estimation example of Explicit memory block size:
Size-of-one-Explicit-memory-block
= allocated-size-of-Explicit-heap-(12,800 Kilobytes)/number-of-Explicit-memory-size-(200)
=64 Kilobytes
The value multiplied with the number of sessions assumed in the businesses is considered as the total memory size of Explicit heap used in the HTTP session.