In this section: |
The Adapter for Adabas provides several parameters for customizing the environment and optimizing performance.
The sections Multifetch and Prefetch, and Adabas Dynamic Database Number describe the environment commands that display and change the parameters governing your server session.
How to: |
ORDER fields maintain the sequence number for each multiply occurring instance. ON is the default value and includes ORDER fields in the list of indexed fields.
Setting ORDERKEYS to OFF forces the Adapter for Adabas to exclude ORDER fields from the list of indexed fields.
Tip: You can change this setting manually or from the Web Console by clicking Adapters on the menu bar, clicking a configured adapter, and choosing Change Settings from the right-click menu. The Change Settings pane opens.
ENGINE ADBSINX SET ORDERKEYS {ON|OFF}
where:
Includes ORDER fields in the list of indexed fields. ON is the default value.
Excludes ORDER fields from the list of indexed fields.
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This setting allows you to switch the access mode from RL to FIND if a field defined with TYPE=NOP was selected (even if CALLTYPE=RL has been specified).
The default value for this setting is MIXED, which uses the default access mode for the selected field. The new setting can be useful when the NOP superdescriptor defined in a root segment is derived from fields that belong to different Master File segments.
Tip: You can change this setting manually or from the Web Console by clicking Adapters on the menu bar, clicking a configured adapter, and choosing Change Settings from the right-click menu. The Change Settings pane opens.
ENGINE ADBSINX SET NOPACCESS {FIND|MIXED}
where:
Switches the access mode from RL to FIND if a field defined with TYPE=NOP was selected (even if CALLTYPE=RL has been specified).
Uses the default access mode for the selected field.
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Setting SYNONYM to NEW instructs the Adapter for Adabas to use new logic when:
Note: This command must be specified in the server profile.
Tip: You can change this setting manually or from the Web Console by clicking Adapters on the menu bar, clicking a configured adapter, and choosing Change Settings from the right-click menu. The Change Settings pane opens.
ENGINE ADBSINX SET SYNONYM {NEW|STD}
where:
Describes superdescriptors as groups in the Master File. With NEW synonym format, neither the groups nor their components (fields) have field names specified in the Master File. Aliases are populated using the Adabas FDT (2-byte name).
When a synonym contains the NEW syntax, the Adapter for Adabas uses NEW logic to process the selection criteria of requests involving that synonym. Screening conditions within the request are analyzed and the superdescriptor that covers the highest order component fields required by the selection criteria are used.
Note that you must specify CALLTYPE=RL in the Access File in order to take advantage of superdescriptor-based access.
Incorporates the usual synonym creation behavior, which does not trigger the new logic for requests using superdescriptors. STD is the default value.
For more information on synonyms, see Creating Synonyms.
The following Master File illustrates superdescriptors Y6 and Y7 defined as GROUP, with the NEW synonym format:
GROUP= ,ALIAS=Y6 ,A2 ,A2 ,INDEX=I,$ FIELD= ,ALIAS=AF ,A1 ,A1 , ,$ FIELD= ,ALIAS=AG ,A1 ,A1 , ,$ GROUP= ,ALIAS=Y7 ,A22 ,A22 ,INDEX=I,$ FIELD= ,ALIAS=AF ,A1 ,A1 , ,$ FIELD= ,ALIAS=AG ,A1 ,A1 , ,$ FIELD= ,ALIAS=AC ,A20 ,A20 , ,$
The corresponding Access File specifies the superdescriptors Y6 and Y7 and their components, using the keywords SUPER and NUMFLDS:
SUPER=Y6 ,NUMFLDS=2 ,$ FIELD=AF_FIELD ,TYPE= ,NU=NO ,$ FIELD=AG_FIELD ,TYPE= ,NU=NO ,$ SUPER=Y7 ,NUMFLDS=3 ,$ FIELD=AF_FIELD ,TYPE= ,NU=NO ,$ FIELD=AG_FIELD ,TYPE= ,NU=NO ,$ FIELD=AC_FIELD ,TYPE= ,NU=NO ,$
SUPER specifies the native Adabas two-byte field name of the superdescriptor.
NUMFLDS defines the number of participating fields. Descriptions of all participating fields immediately follow the SUPER statement.
The request that follows uses superdescriptor Y6 in the L3 (Read Logical) command in the Access File:
TABLE FILE EMP211 PRINT AF_FIELD AG_FIELD AC_FIELD AD_FIELD IF AF_FIELD EQ 'S' IF AG_FIELD EQ 'M' END
The next request uses superdescriptor Y7 in the L3 (Read Logical) command. Notice that it references an extra field in the last line of the Access File:
TABLE FILE EMP211 PRINT AF_FIELD AG_FIELD AC_FIELD AD_FIELD IF AF_FIELD EQ 'S' IF AG_FIELD EQ 'M' IF AC_FIELD EQ 'C' END
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The Adabas Multifetch and Prefetch options reduce execution time and allow Adabas data to be retrieved with a high degree of efficiency. By buffering multiple record results from a single call, Multifetch and Prefetch reduce the communication overhead between the Adapter for Adabas and the Adabas nucleus.
The adapter uses the Multifetch option if it is available (this is the default option), or the Prefetch option if it is available. The option available is determined by your environment.
The adapter trace file contains the following information about the Fetch option:
The Multifetch and Prefetch options require that OPEN=YES (the default value) is specified in the Access File. When OPEN=YES is specified, the Multifetch and Prefetch options are activated. There are two ways to deactivate (or reactivate) these options:
Note: The SET commands override the Access File settings. This setting will be in effect for the entire server session.
Tip: You can change this setting manually or from the Web Console by clicking Adapters on the menu bar, clicking a configured adapter, and choosing Change Settings from the right-click menu. The Change Settings pane opens.
ENGINE ADBSINX SET FETCH {ON|OFF|DEFAULT} ENGINE ADBSINX SET FETCHSIZE {n|MAX[IMUM]}
where:
Indicates the adapter. You can omit this value if you previously issued the SET SQLENGINE command.
Sets the Fetch feature on for the user session.
Sets the Fetch feature off for the user session.
Uses the information from the Access File. DEFAULT is the default value.
Is the number of records per buffer (1–32K). The buffer size varies with the size of the record and can be different for each TABLE request. The buffer size limit is 32K. 10 is the default value.
Is automatically calculated by the Adapter for Adabas to allow the maximum number of records that fit in a 32K buffer.
FETCH and FETCHSIZE are applicable only to segments described as ACCESS=ADBS in the Access File.
The Access File can contain the following attributes in the SEGNAM statement
FETCH={ON|OFF} FETCHSIZE={n|MAX[IMUM]}
where:
Sets the Fetch feature on for the user session. ON is the default value.
Sets the Fetch feature off for the user session.
Is the number of records per buffer (1 to 32k). 10 is the default value.
Is automatically calculated by the Adapter for Adabas to allow the maximum number of records that fit in a 32K buffer.
Here is an example of the FETCH and FETCHSIZE attributes in the sample Access File for EMPLOYEES:
$$$ FILENAME=EMPFILE1,SUFFIX=ADBSINX,$
RELEASE=6,OPEN=YES,$
$ ADABAS FILE = EMPLOYEES DICTIONARY =
SEGNAM=S01 ,ACCESS=ADBS,FILENO=001,CALLTYPE=RL,
SEQFIELD=PERSONNEL_ID,FETCH=ON,FETCHSIZE=15,$
FIELD=DEPT_PERSON ,TYPE=SPR,$
FIELD=DEPT_S03 ,TYPE=DSC,NU=YES,$
FIELD=NAME_S03 ,TYPE= ,NU=NO,$
See your Software AG documentation for more information about the Multifetch/Prefetch feature.
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You can use the FETCHJOIN command to take advantage of Multifetch efficiencies in Join operations for a session. This feature is particularly useful when you are joining to a base file in which sorting is based on the key field that is used for the join.
Tip: You can change this setting manually or from the Web Console by clicking Adapters on the menu bar, clicking a configured adapter, and choosing Change Settings from the right-click menu. The Change Settings pane opens.
ENGINE ADBSINX SET FETCHJOIN {ON|OFF}
where:
Indicates the adapter. You can omit this value if you previously issued the SET SQLENGINE command.
Sets the FETCHJOIN feature on for the user session. ON is the default value.
Sets the FETCHJOIN feature off for the user session. This value is recommended when joining with a base file that is unsorted by the key field used for joining. This option avoids buffering and reduces processing time.
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Previous versions of the Adapter for Adabas required specification of the Adabas database number in the Access File using the DBNO attribute. This feature required a duplicate copy of the Access File for each database accessed.
Adabas database numbers can now be set from the server's profile. This SET command allows users to override the DBNO in the Access File. Note that specifying database numbers in the Access File is still supported. Use of the dynamic database number makes Master and Access Files shareable among databases.
The SET command remains valid throughout the server session.
Tip: You can change this setting manually or from the Web Console by clicking Adapters on the menu bar, clicking a configured adapter, and choosing Change Settings from the right-click menu. The Change Settings pane opens.
ENGINE ADBSINX SET DBNO dbno ENGINE ADBSINX SET DBNO dbno AFD afd ENGINE ADBSINX SET DBNO dbno AFD afd SEG[NAM] segname ENGINE ADBSINX SET ? ENGINE ADBSINX SET DBNO DEFAULT
where:
Indicates the adapter. You can omit this value if you previously issued the SET SQLENGINE command.
Is any valid numeric database value between 0 and 255.
Is any valid Access File name.
Is any valid ADBS segname in the Access File.
Queries the current settings.
Returns to the default settings for all previous settings. The DBNO is read from the Access File. If the attributes are not specified in the Access File, the adapter will determine the DBNO from the DDCARD.
Examples for z/OS are shown below:
ENGINE ADBSINX SET DBNO 5 |
Retrieves all data from database number 5. |
ENGINE ADBSINX SET DBNO 2 AFD EMPFILE |
Retrieves data for the EMPFILE from database number 2. |
Note: Several commands can be issued for different files. Each command must be issued separately. Changes are cumulative. For example:
ENGINE ADBSINX SET DBNO 1 AFD EMPFILE ENGINE ADBSINX SET DBNO 2 AFD EMP2 ENGINE ADBSINX SET DBNO 3 AFD VEHICLES
ENGINE ADBSINX SET DBNO 2 AFD EMPFILE SEG S02 |
Retrieves data for the EMPFILE in database number 2 for a particular ADBS segment (segment S02). |
ENGINE ADBSINX SET ? |
Displays your settings. |
ENGINE ADBSINX SET DBNO DEFAULT |
Returns to the default settings. This resets all SET DBNO commands for all Access Files. |
The SET CALLTYPE command enables you to set the data retrieval type per session, file, or segment by switching dynamically between physical and logical reads.
Tip: You can change this setting manually or from the Web Console by clicking Adapters on the menu bar, clicking a configured adapter, and choosing Change Settings from the right-click menu. The Change Settings pane opens.
The following examples illustrate the use of variations of dynamic CALLTYPE syntax:
Uses FIND as the type of data retrieval call for all files.
Retrieves data for the EMPFILE using RL as the type of data retrieval call.
Note that you can issue several commands for different files. Each command must be issued separately. Changes are cumulative. For example, the following commands retrieve data for the EMPFILE using FIND as the type of data retrieval call for a particular ADBS segment (segment S02):
ENGINE ADBSINX SET CALLTYPE RL AFD EMPFILE
ENGINE ADBSINX SET CALLTYPE FIND AFD EMP2
ENGINE ADBSINX SET CALLTYPE MIXED AFD VEHICLES
ENGINE ADBSINX SET CALLTYPE FIND AFD EMPFILE SEGNAME S02
Displays your settings.
Returns to the default settings. This command resets all SET CALLTYPE commands for all Access Files.
The SET LAFORMAT command affects Metadata for fields with LA options:
ENGINE ADBSINX SET LAFORMAT {DEFAULT|TX|Annnnn}
where:
Maps the ADABAS LA field as fixed-length A500, A500.
Maps the ADABAS LA field as text TX50, TX.
(253 < nnnnn < 16382) maps LA field with a specified given range length.
The command sets specified code-page on the field level when mapping ADABAS Unicode W-fields.
ENGINE ADBSINX SET WCODEPAGE {DEFAULT|OFF|nnnnn}
where:
Corresponds to codepage 65003.
Means to process W as A (without conversion).
Means any valid codepage.
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