7.11.2 Mechanism of reducing memory usage
The Explicit memory block in the Explicit heap area, in which an HTTP session is stored, is created every time the application creates an HTTP session. Objects related to the HTTP session are placed in the created Explicit memory block.
This subsection describes the mechanism of reducing the memory usage by comparing the cases when you do not use this functionality and when you use this functionality.
- Organization of this subsection
(1) When you do not use the memory saving functionality of the Explicit heap that is used in an HTTP session
The following figure shows an example where there are three Explicit memory blocks in which objects related to an HTTP session are stored. From among these three blocks, B and C Explicit memory blocks are less utilized. The Explicit memory blocks are associated with the HTTP sessions that are not used for long time.
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![[Figure]](GRAPHICS/ZU081150.GIF)
If you are not using the memory saving functionality of the Explicit heap that is used in an HTTP session, the Explicit memory blocks A-C are not released even when an automatic release occurs. In this case, used size of the Explicit memory block, in which objects related to an HTTP session are stored, matches with total bytes of the objects related to an HTTP session. Also, the number of Explicit memory blocks matches with the number of active sessions.
However, even when you store a small-sized object, the Explicit memory block is secured with a size that is above a fixed size. Therefore, the memory of the Explicit heap area, more than the Explicit memory size actually required, is consumed.
(2) When you use the memory saving functionality of the Explicit heap that is used in an HTTP session
The following figure shows an example where there are three Explicit memory blocks in which objects related to an HTTP session are stored. From among these three blocks, B and C Explicit memory blocks are less utilized. The Explicit memory blocks are associated with the HTTP sessions that are not used for a long time. The example also shows D as an Explicit memory block in which objects specified in an automatic placement configuration file are stored.
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![[Figure]](GRAPHICS/ZU081160.GIF)
If you are using the memory saving functionality of the Explicit heap that is used in an HTTP session, the memory saving functionality of the Explicit heap that is used in an HTTP session is executed when automatic release occurs. Explicit memory blocks B and C, which are less utilized, are released. Objects related to an HTTP session, which was stored in this Explicit memory block, move to D.
Thus, the utilization of Explicit memory blocks improves by moving and consolidating the objects stored in the less-utilized Explicit memory blocks to the other area and by releasing the less-utilized Explicit memory blocks.