The following /REGION qualifiers can be used with the ADD, CHANGE, or TEMPLATE commands.
/C[OLLATION_SEQUENCE]=id number Applies to: BG MM
/COLLATION_SEQUENCE=ID number specifies the number of the collation sequence definition to be used as the default for this database file. The number can be any integer between zero (0) and 255. The number you assign as a value must match the number of a defined collation sequence that resides in the executable image pointed to by the logical name GTM_COLLATE_n. For information on defining this logical name and creating an alternative collation sequence, refer to the "Internationalization" chapter in the GT.M Programmer's Guide.
The minimum COLLATION_SEQUENCE ID number is zero, which is the standard M collation sequence.
The maximum COLLATION_SEQUENCE ID number is 255.
By default, GDE uses zero (0) as the COLLATION_SEQUENCE ID.
/D[YNAMIC_SEGMENT]=segment-name Applies to: BG MM
Specifies the name of the segment to which the region is mapped. Segment-names are not case-sensitive, but are displayed as uppercase by GDE.
The minimum length is one alphabetic character.
The maximum length is 16 alphanumeric characters.
/K[EY_SIZE]=size in bytes Applies to: BG MM
Specifies the maximum size of keys, in bytes, which can be stored in the region. The KEY_SIZE must be less than the RECORD_SIZE. GDE rejects the command if the KEY_SIZE is greater than the RECORD_SIZE.
The minimum KEY_SIZE is three bytes.
The maximum KEY_SIZE is 255 bytes.
By default, GDE uses a KEY_SIZE of 64 bytes.
/R[ECORD_SIZE]=size in bytes Applies to: BG MM
Specifies the maximum RECORD_SIZE, in bytes, which can be stored in the region. The KEY_SIZE must be less than the RECORD_SIZE. GDE rejects the command if the KEY_SIZE exceeds the RECORD_SIZE.
If the RECORD_SIZE is greater than the BLOCK_SIZE minus the number of reserved bytes, minus the size of the record header (7 or 8 bytes, depending on your platform), GDE issues an error message.
The minimum RECORD_SIZE is seven.
The maximum RECORD_SIZE is 32,767 bytes.
By default, GDE uses a RECORD_SIZE of 256 bytes.
/[NO]N[ULL_SUBSCRIPTS] Applies to: BG MM
Indicates whether GT.M allows null subscripts for global variables stored in the region (i.e., whether GT.M permits references such as ^aaa("",1)).
By default, regions have /NONULL_SUBSCRIPTS.
/[NO]J[OURNAL][=journal-option-list] Applies to: BG MM
Specifies whether the database file allows journaling. If it does, this qualifier establishes characteristics for the journal file.
/NOJOURNAL specifies that updates to the database file are not journaled. /NOJOURNAL does not accept an argument assignment.
/JOURNAL specifies that journaling is allowed. /JOURNAL takes one or more arguments in a journal-option-list. The journal-option-list contains keywords separated with commas (,) enclosed in parentheses ( ). If the list contains only one keyword, the parentheses are optional.
Although you do not have to establish the criteria for your journaling process at this point, it is efficient to do so, even if you are not entirely sure you will use journaling. The options available for /JOURNAL set up the environment, so it is ready for you to enable with MUPIP SET /JOURNAL. You can also change or add any of the established options at that time.
For more information about journaling, refer to the "GT.M Journaling" chapter.
The journal-option-list includes:
[NO]BE[FORE_IMAGE]
F[ILE_NAME]=file-specification-name
A[LLOCATION]=blocks
E[XTENSION]=blocks
BU[FFER_SIZE]=pages
The following section describes some /JOURNAL options.
/[NO]BE[FORE_IMAGE]Applies to: BG
[NO]BEFORE_IMAGE controls whether the journal should capture before images of information that an update is about to modify.
The BEFORE_IMAGE option is required if you plan to consider "roll-back" (Backward) recovery of the associated database file or if you plan to use database replication. For a description of this type of recovery, refer to the "GT.M Journaling" chapter.
/F[ILE_NAME]=file-specification Applies to: BG MM
/F[ILE_NAME]=file-specification specifies the name of the journal file.
The name should always be enclosed in quotation marks in this context.
Journal file-specifications-names are limited to 255 characters.
By default, GDE derives the file-specification-name from the database file-specification.
By default, GDE uses a journal file extension of .MJL.
/A[LLOCATION]=blocks Applies to: BG MM
ALLOCATION=blocks specifies the initial size of the journal file in RMS blocks. The default ALLOCATION was chosen for small development projects. Because frequent journal file extensions degrade run-time performance, make journal file ALLOCATION ample for a production database file.
When you change the ALLOCATION and do not also specify EXTENSION, the EXTENSION automatically changes to equal the ALLOCATION.
The minimum allocation is 10 blocks.
The maximum allocation is 16777216 blocks.
By default, GDE uses an allocation of 100 blocks.
/E[XTENSION]=blocks Applies to: BG MM
EXTENSION=blocks specifies the size by which a journal file extends when it becomes full. EXTENSION=0 prevents automatic journal file extension. The default EXTENSION amount was chosen for small development projects. Use larger extensions for larger files. Because frequent journal file extensions degrade run-time performance, make the journal file EXTENSION ample for a production database file.
When you change the ALLOCATION and do not also specify EXTENSION, the EXTENSION automatically changes to equal the ALLOCATION.
The minimum EXTENSION is zero blocks.
The maximum EXTENSION is 65535 blocks.
By default, GDE uses an EXTENSION of 100 blocks.
/BU[FFER_SIZE]=pages Applies to: BG MM
BUFFER_SIZE=pages specifies the amount of memory used to buffer journal file output. A larger BUFFER_SIZE usually smooths and improves run-time performance.
A larger BUFFER_SIZE requires more memory resources, which may be scarce.
The minimum BUFFER_SIZE is enough 512-byte pages to hold two GDS database blocks.
The maximum BUFFER_SIZE is 2000 pages.
By default, GDE uses a BUFFER_SIZE of 128 pages.