gtpd1m0wDatabase Reference

VFA Candidate Records

You can define record groups for VFA candidates with the following attributes:

Delay Filing
When a FILE macro is issued, the record is copied to VFA and not written to file until:

In a loosely coupled environment, this record is not synchronized between processors. That is, other processors accessing this record will not see the version of this record in any other processors VFA.

Synchronized Delay Filing
When a FILE macro is issued, the record is only physically written to DASD when:

Immediate Filing
When a FILE macro is issued, the record is copied to VFA and is immediately filed. In a loosely coupled environment, this record is not synchronized between processors. That is, other processors accessing this record will not see the version of this record in any other processors VFA.

Synchronized Immediate Filing
When a FILE macro is issued, the record is copied to VFA and is immediately filed. When another processor signals that it wants to use the record, the copy in VFA is invalidated.

Data record processing occurs for the following general macros:

See TPF General Macros for more information about these macros.

The following general and system macros cause the target record to be flushed from VFA if the target record is in VFA:

Note:
For records defined as VFA synchronization candidates, flushing is only performed on the processor that issues the FNSPC or FLSPC macro. Flushing is not performed on all processors. This could lead to database integrity problems.

See TPF General Macros for more information about the FINSC and FILSC macros. See TPF System Macros for more information about the FNSPC and FLSPC macros.

VFA program record processing occurs for the following general macros:

See TPF General Macros for more information about these macros.

Whenever VFA delay filing is selected and active (both normal delay filing and synchronized delay filing), it is possible for an application program to retrieve a record from file using the FDCTC macro while a more recent copy of the record exists in a VFA buffer. For this reason, it is essential that any application program that manages data records using the FDCTC macro not be processed while delay filing or synchronized delay filing is active.

Note:
Delay filing is active only in NORM state when one or more VFA candidate records has been defined with the delay file or synchronized delay filing attribute. You can use the capture and restore utility while VFA is active.

Data records are defined as VFA candidates by record ID. Program records are defined as VFA candidates by record ID as well. Special record ID X'00FF' in the record ID attribute table (RIAT) describes the candidacy of all file resident programs.

Note:
Program records are VFA candidates when they are retrieved for the ENTRC, ENTNC, ENTDC, or GETPC macros only.

If a program record that is resident in VFA is accessed by a FILSC, FILEC, FILUC, or FILNC macro, the record is flushed from the VFA buffers.

See TPF Operations for more information about the ZRTDM DISPLAY and ZRTDM MODIFY commands, and for information about displaying and modifying VFA candidacy in the RIAT.