Identifies the DMCL with which the database buffer is associated. Dmcl-name must name an existing DMCL defined to the dictionary. If you don't specify a DMCL name, you must establish a current DMCL as described in 7.3.3, “Entity Currency".
Specifies the name of the buffer being created. Database-buffer-name must be a 1- through 18-character name that follows the conventions described in 7.3, “Naming Conventions".
Database-buffer-name must be unique among the database and journal buffer names within the DMCL. From 1 to 32,767 database buffers can be defined to a single DMCL.
Specifies the number of characters in each page of the buffer. This clause is required on a CREATE statement. The buffer page size determines the size of the largest database page or VSAM control interval that can be written to the buffer.
The value of character-count depends on the type of buffer being defined:
|
File |
Buffer Type |
Valid Page Sizes (in bytes) |
|---|---|---|
|
VSAM database file |
|
48 - 32764; multiple of 4 1 2 |
|
Native VSAM file3 |
LSR |
512, 1024, 2048, or multiple of 4096 up to 28672 |
|
|
NSR |
512 - 8192; multiple of 512 8193 - 30720; multiple of 2048 |
Note: For VSAM database files, character-count must be at least 8 bytes larger than the size of the database page.
Note: For native VSAM files, the PAGE SIZE clause must be greater than or equal to the largest control interval of a file that maps to the buffer.
Specifies a buffer for use with native VSAM data sets.
Specifies an LSR (local shared resource) buffer. Only one is allowed per DMCL.
Lsr-key-length specifies the maximum key length for all native VSAM files using the buffer, where lsr-key-length-n is an integer in the range 1 through 255.
Specifies an NSR (nonshared resource) buffer. Any number of these are allowed.
Index-buffer-count specifies the number of index buffers VSAM uses to transfer the contents of index entries between main memory and auxiliary storage. It is an integer in the range string-number through 32767.
Specifies the maximum number of concurrent requests permitted against all areas associated with files that are assigned to the buffer, where string-number is an integer in the range 1 through 255.
Specifies the number of pages to be included in the buffer when the database is used in local mode. Valid values for local-mode-page-count appear as follows:
|
Buffer Type |
Valid Values |
|---|---|
|
Non-native VSAM buffers |
3 to 16,777,2141; default 3 |
|
Native VSAM buffers |
2 to 256; must be greater than the value assigned to STRNO in the NATIVE VSAM clause above |
Note: The practical upper limit depends on the amount of available storage.
Native VSAM: For native VSAM data sets, the buffer page count specifies the number of pages in the buffer used to transfer data between memory and auxiliary storage. For LSR buffers, the page count specifies the number of pages used to transfer both data and index entries.
Places the buffer in a contiguous block of storage acquired from the operating system. The storage is acquired above the 16-megabyte line in operating systems that support extended addressing. If sufficient storage is not available, storage is acquired as IDMS storage. OPSYS STORAGE is the default.
Acquires a discrete piece of storage for each buffer page. If the operating system supports extended addressing, the storage will be acquired above the 16-megabyte line.
Native VSAM: Do not specify this clause.
Specifies page counts for the buffer when the database is used under the central version.
Specifies options for the buffer used under the central version.
Specifies the initial number of pages to be allocated for the buffer. Initial-page-count is an integer. Valid values appear as follows:
|
Buffer Type |
Valid Values |
|---|---|
|
Non-native VSAM buffers |
3 to 16,777,2141; default 3 |
|
Native VSAM buffers |
2 to 256; must be greater than the value assigned to STRNO in the NATIVE VSAM clause above |
Note: The practical upper limit depends on the amount of available storage.
Native VSAM: For native VSAM data sets, the buffer page count specifies the number of pages in the buffer used to transfer data between memory and auxiliary storage. For LSR buffers, the page count specifies the number of pages used to transfer both data and index entries.
Specifies the largest number of pages that can be allocated for the buffer. Maximum-page-count is an integer in the range 3 to 16,777,214. It must be greater than or equal to the number specified in the INITIAL PAGES parameter. The default is the initial number of pages included in the buffer.
Native VSAM: Do not specify this clause.
Places the buffer in contiguous storage acquired from the operating system. OPSYS STORAGE is the default.
The storage is acquired above the 16-megabyte line in operating systems which support extended addressing. If sufficient storage is not available, storage is acquired as IDMS storage.
Requests a discrete piece of storage for each buffer page from the DC/UCF storage pool. If the DC/UCF system contains a storage pool above the 16-megabyte line, then storage for the buffer is acquired above the 16-megabyte line.
Native VSAM: Do not specify this clause.
Displays or punches details about the database buffer.
Displays or punches:
Displays or punches all information about the database buffer. ALL is the default action for a DISPLAY or PUNCH verb.
Displays or punches the name of the database buffer.
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