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 AG.

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