Buffer Parameters

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# Buffer Parameters

Buffer parameters control the operation of the Adabas Fastpath buffer.

Buffer Parameters
`Additional Encodings`
`Async Coherence Messages`
`Average Item Size`
`Coherence Limit and Suspension Period`
`Dataspace Name`
`Default Pacing Rate`
`Direct Access`
`Fast Cache Attempts`
`Fast Set Create Attempts`
`Find (Sx/L1)`
`Freespace Index`
`Histogram`
`Keep`
`Log`
`Maximum Jobs`
`Message Level (Hex)`
`Minimum Buffer Size`
`RB Length Limit`
`Read Ahead`
`Read Logical (L3)`
`Read Physical (L2)`
`Restart Every n Hours`
`Restart Time`
`Set Concurrency`
`Set ID Length Limit`
`Size`

## Additional Encodings

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | Controls whether data in a character encoding other than that used by the database/file to hold the data can be cached. | Default None All Single byte ascii Single byte ebcdic Double byte ascii Double byte ebcdic | None

## Async Coherence Messages

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | This parameter indicates whether synchronous or asynchronous communication is to be used for retaining cache coherence in remote systems from where the update thread executes. There may be some performance gain by using asynchronous mode but the safest mechanism is synchronous. | Y | N | Y

## Average Item Size

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | All memory allocations within the Adabas Fastpath buffer are recorded in an index. This parameter is used as a divisor into the buffer size to decide how many items will be expected within the first index block. | 64 | 32768 | 1024

## Coherence Limit and Suspension Period

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | There is more overhead required by Fastpath to distribute update information across multiple systems (lpars) where distributed caching/optimization for direct-access is used. In periods of intensive update activity this can be counter-productive. These controls allow you to set a threshold where direct-access optimization is suspended for a file if the amount of inter-system update notification breaches a certain level - and then resumed at a later period automatically. This allows Fastpath to react sensibly and dynamically to "floods" of updates. Coherence Limit The number of distributed update operations to a file per second, as an average over the period of a minute, that will cause the file to temporarily suspend direct access optimization. Suspension Period The number of minutes that direct-access optimization (etc.) is suspended when the coherence limit is breached. It is automatically resumed after this period. If a zero value is input into the online system for either of these parameters, the default value will be used | Coherence Limit: 0-32767 Suspension Limit: 0-32767 | Coherence Limit: 64 Suspension Limit: 10

## Dataspace Name

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | This controls where the Fastpath buffer is allocated. If a name is specified the Fastpath buffer is allocated as a dataspace. The Fastpath buffer can be allocated as a dataspace to alleviate shortages of shared memory, a critical resource. This feature allows you to run with the z/OS setting of `USERCSAKEY=NO` as recommended by IBM. For backwards compatibility the default remains shared memory (ECSA). If you are using Adabas System Coordinator Version 8.3.1 (or above), refer to the daemon runtime parameter `DSPSCOPE` for information on the type of dataspace available for use. For more information on dataspaces please refer to IBM documentation SA22-7614-00, MVS Programming: Extended Addressability Guide, second edition October 2001, which applies to z/OS. | 1-8 characters with no embedded blanks. First character must be #, @ or J-Z. All other characters must be letters, numbers, #, @ or $. The name must not begin with "SYSA" through "SYSI". | None

## Default Pacing Rate

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
File | Expressed as a percentage, this parameter controls the rate at which housekeeping is performed by FASTABM. If a value of 0 is entered, then the Buffer parameter value is assumed. It is recommended this parameter is only modified when you are instructed to do so by Software GmbH. | 0-100 | 10

## Direct Access

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | Defines the optimization settings at the buffer level. OFF prevents direct-access optimization altogether. ON enables direct-access optimization according to the file and job parameters that are defined. | ON | OFF | ON

## Fast Cache Attempts

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | The number of records to be cached in high-speed mode in order to accelerate the learning period of the direct-access algorithm (per set). Once this number is reached the normal asynchronous caching mechanism is used. | 0-255 | 32

## Fast Set Create Attempts

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | The number of sets to be created in high-speed mode in order to accelerate the learning period of the direct-access algorithm. Once this number is reached the normal asynchronous mechanism is used. | 0-255 | 25

## Find (Sx/L1)

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | Defines the optimization settings for these commands at the buffer level. OFF prevents optimization altogether. ON enables optimization according to the file and job parameters that are defined. | ON | OFF | ON

## Freespace Index

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | All free memory in the Adabas Fastpath buffer is classified into a fixed-size freespace index. This parameter sets the number of different freespace categories (entries) in the index. | 16 | 32768 | 512

## Histogram (L9)

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | Defines the optimization settings for this command at the buffer level. OFF prevents optimization altogether. ON enables optimization according to the file and job parameters that are defined. | ON | OFF | ON

## Keep

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | Determines the number of days that the statistics log is to be retained. When automatic statistic logging is enabled (see the parameter Log), any entries that are younger than n days will be kept for each buffer in the Configuration file. Older entries will be subject to eventual overlay. | 1 | 32768 | 30

## Log

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | Controls how often the statistics log is to be written (specified in minutes). A statistics log record is written to the Adabas Fastpath configuration file by the Adabas Fastpath asynchronous buffer manager every n minutes. A value of 0 implies no automatic logging but does not prevent logs being requested by using the Adabas Fastpath Online Special Services function. See also the parameter `Keep`. | 0 | 32768 | 60

## Maximum Jobs

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | This parameter indicates the maximum number of optimized jobs which are to be run concurrently. The corresponding number of job areas are then reserved. If an area is not available, additional (concurrent) jobs are not optimized. One area is required for each individual job name operating under any of the following job types: - Batch - COM-PLETE - CICS (DTR) - CICS (Standard) - TSO - TIAM - Single-TCB - Multi-TCB For a job-type of UTM (DTR), one area is required for each concurrently active task (plus 1). For a job-type of IMS (DTR), one area is required for each application processing region (plus 1). Refer to the Current Activity Displays, Buffer Information, General Parameters screen in SYSAFP in order to monitor the usage of this parameter. | 1 | 9999 | 12

## Message Level (Hex)

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | This parameter indicates the minimum severity of messages to be issued by Adabas Fastpath running in the daemon. Note The New Buffer message issued during Buffer initialization is always issued. | 1 | FF | 0 (all messages will be output)

## Minimum Buffer Size

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | Defines the minimum buffer memory size (in k) to be requested from the operating system for the Adabas Fastpath buffer. If the value is 0, the buffer parameter `Size` is the only value used. | 0 | value | 0

## RB Length Limit

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | Restricts the size of buffer used for evaluating data for direct access optimization. A file parameter value can be used to restrict the buffer parameter setting. A file parameter with a value of zero is ignored. | 16 | 32768 | 1024

## Read-Ahead

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | Defines the optimization settings at the buffer level. OFF prevents read-ahead optimization altogether. ON enables read-ahead optimization according to the file and job parameters that are defined. | ON | OFF | ON

## Read Logical (L3)

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | Defines the optimization settings for this command at the buffer level. OFF prevents optimization altogether. ON enables optimization according to the file and job parameters that are defined. | ON | OFF | ON

## Read Physical (L2)

Parameter Type | Use | Possible Values | Default
--- | --- | --- | ---
Buffer | Defines the optimization settings for this command at the buffer level. OFF prevents optimization altogether. ON enables optimization according to the file and job parameters that are defined. | ON | OFF | ON

## Restart Every n Hours

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | Indicates frequency of automated buffer restarts. If the value is not zero, it indicates the minimum number of hours that must elapse since the last buffer start/restart before auto-restart may occur. | 0 | 999 | 0

## Restart Time

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | Indicates the time at which automated restarts should occur. Entered as hours and minutes in the 24-hour clock. The default is midnight. | 0 | 23:59 | 0

## Set Concurrency

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | This parameter indicates the number of concurrent retrievals which can occur from each set of direct access data created by Adabas Fastpath. A file parameter value can be used to restrict the buffer parameter setting. A file parameter with a value of zero is ignored. | 1 | 16 | 2

## Set ID Length Limit

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | Adabas Fastpath uses direct access set identifiers which contain search and format data for direct access command models. This parameter limits the size of data items within each set. A file parameter value can be used to restrict the buffer parameter setting. A file parameter with a value of zero is ignored. | 256 | 16384 | 1024

## Size

Parameter Type | Use | Minimum | Maximum | Default
--- | --- | --- | --- | ---
Buffer | This parameter defines the size (in k) of the memory to be allocated to the Adabas Fastpath buffer. When requesting the memory from the operating system, the value actually obtained depends on the setting of the parameter `Minimum Buffer Size`. | 1MB |  | 4MB

### On this page

- Additional Encodings
- Async Coherence Messages
- Average Item Size
- Coherence Limit and Suspension Period
- Dataspace Name
- Default Pacing Rate
- Direct Access
- Fast Cache Attempts
- Fast Set Create Attempts
- Find (Sx/L1)
- Freespace Index
- Histogram (L9)
- Keep
- Log
- Maximum Jobs
- Message Level (Hex)
- Minimum Buffer Size
- RB Length Limit
- Read-Ahead
- Read Logical (L3)
- Read Physical (L2)
- Restart Every n Hours
- Restart Time
- Set Concurrency
- Set ID Length Limit
- Size