Client Session Memory Requirements

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# Client Session Memory Requirements

The following table lists the main memory requirements for an Adabas Vista client session.

Note
This table is not intended to be an exhaustive list of the memory requirements. It is recommended that you use this table during the initial analysis of a system's memory requirements. Once implemented, Adabas System Coordinator Online Services may be used to more accurately monitor the amount of real memory in use.

Memory requirement (per session) for each... |  | Size (in bytes)
--- | --- | ---
session area (one only) |  | 512
database accessed |  | + 160
file accessed | Adabas file | + 80
Adabas Vista translation file | + 80 + 64 + 48
Adabas Vista Standard partitioned file | + 80 + 64 + (48 + partitioning field length + partition concurrency * 5) * number of partitions.
Adabas Vista Extreme partitioned file | As Standard partitioned file + 32K (TP system) OR + 1024K (Batch)
Command ID issued against | an Adabas file | + 80
an Adabas Vista translation file | + 36 + 80
an Adabas Vista partitioned file | + (256 + 80 * number of involved partitions) + (length of Adabas buffers * number of involved partitions)
record held (within a transaction) against | an Adabas file | + 64
an Adabas Vista translation file | + 64
an Adabas Vista partitioned file | + 64 * number of involved partitions

#### Example

1. Estimate the per session memory requirements for an application which has the following characteristics:

   - two databases

   - five Adabas files

   - two Adabas Vista translation files

   - one Adabas Vista Standard partitioned file

     - Partitioning field length is eight bytes

     - User partition concurrency is eight

     - Number of partitions is three

     - Majority of access is distributed (all three partitions involved)

     - Average length of Adabas buffers is 1000 bytes

   - Maximum Command ID concurrency of two (one Adabas file and one Adabas Vista partitioned file)

   - Average number of successful hold commands between `ET/BT` is 20

     - 18 against Adabas files

     - two against Adabas Vista partitioned file

   #### Result

   User session area: |  | 512
   Database requirements: | (2 * 160) | 320
   File requirements: | (5 * 80) + (2 * 192) + 1 * 432 | 1216
   Command ID requirements: | 80 + 3496 | 3576
   Held record requirements: | 18 * 64 + 2 * (64 * 3) | 1536
   | Total | 7160

2. Multiply this value by the estimated number of application clients to estimate the application memory requirements.

3. If a single TP system is host to multiple applications, repeat this process for each application to provide an overall estimate of the TP memory requirements.

The required memory is requested from either

- local TP memory using the host TP services; or

- shared memory using the Adabas System Coordinator daemon.

The use of shared memory depends on whether the job is defined as a clustered application using job types such as CICS Cluster, IMS, or UTM.

Note
It is strongly recommended that you discuss the use of such job types with your system programmer before you implement them.