Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (D-E)
Guardian Procedure Calls Reference Manual—522629-013
4-5
DEALLOCATESEGMENT Procedure
(Superseded by SEGMENT_DEALLOCATE_
an outstanding nowait I/O operation using a buffer in the segment has not
been completed by a call to AWAITIOX.
= (CCE) Segment deallocated.
> (CCG) Segment deallocated, but an I/O error occurred writing dirty pages to the
segment’s permanent swap file.
Considerations
•
The flags parameter
The
flags.<15> = 1 option is used to improve performance when the swap file is
either a permanent file or a temporary file that is opened concurrently by another
application. Following the DEALLOCATESEGMENT call, the contents of the swap
file are unpredictable.
If the DEALLOCATESEGMENT call causes a purge of a temporary file or the
DEALLOCATESEGMENT call deallocates swap space managed by the Kernel-
Managed Swap Facility (KMSF), the operating system does not write the dirty
pages (that is, pages that are being used) out to the file.
•
Breakpoints
Before deallocating a segment, this procedure removes all memory access
breakpoints set in that segment.
•
Segment deallocation
When a segment is deallocated, the swap file end of file (EOF) is set to the larger
of (1) the EOF when the file is opened by ALLOCATESEGMENT or (2) the end of
the highest numbered page that is written to the swap file. All file extents beyond
the EOF that did not exist when the file was opened are deallocated.
•
Shared segments
A shared segment remains in existence until it has been deallocated by all the
processes that allocated it.
Example
CALL DEALLOCATESEGMENT ( SEGMENT^ID );
IF <> THEN ...
! SEGMENT^ID refers to the segment number specified
! in the call to ALLOCATESEGMENT.