JOURNAL BUFFER Statements

The JOURNAL BUFFER statements create, alter, drop, display, or punch the definition of a journal buffer in the dictionary. For each DMCL, you must define one and only one journal buffer.
idms
The JOURNAL BUFFER statements create, alter, drop, display, or punch the definition of a journal buffer in the dictionary. For each DMCL, you must define one and only one journal buffer.
Authorization
  • To create, alter, or drop a journal buffer, you must have the following privileges:
    • DBADMIN on the dictionary in which the journal buffer definition resides
    • ALTER privilege on the DMCL with which the journal buffer is associated
  • To display or punch a journal buffer, you must have DISPLAY privilege on the DMCL with which the journal buffer is associated or DBADMIN on the dictionary in which the journal buffer definition resides
Syntax
CREATE/ALTER JOURNAL BUFFER
►►─┬─ CREATE ─┬─ JOURNAL BUFFER ─┬──────────────┬─ journal-buffer-name ───────► └─ ALTER ──┘ └─ dmcl-name. ─┘ ►─┬────────────────────────────────────────┬─────────────────────────────────► └─ PAGE SIZE character-count characters ─┘ ►─┬───────────────────────────┬──────────────────────────────────────────────►◄ └─ BUFFER PAGES page-count ─┘
DROP JOURNAL BUFFER
►►── DROP JOURNAL BUFFER ─┬──────────────┬─ journal-buffer-name ──────────────►◄ └─ dmcl-name. ─┘
DISPLAY/PUNCH JOURNAL BUFFER
►►─┬─ DISplay ─┬─ JOURNAL BUFFER ─┬──────────────┬─ journal-buffer-name ──────► └─ PUNch ───┘ └─ dmcl-name. ─┘ ┌───────────────────────────────────────┐ ►─▼─┬───────────────────────────────────┬─┴──────────────────────────────────► │ ┌────────────────┐ │ ├─ WITh ──────┬─▼─┬─ DETails ──┬─┴──┘ └─ WITHOut ───┘ ├─ HIStory ──┤ ├─ ALL ◄─────┤ └─ NONe ─────┘ ►─┬────────────────────────┬─────────────────────────────────────────────────► └─ VERb ─┬─ DISplay ───┬─┘ ├─ PUNch ─────┤ ├─ CREate ◄───┤ ├─ ALTer ─────┤ └─ DROp ──────┘ ►─┬───────────────────────┬──────────────────────────────────────────────────►◄ └─ AS ─┬─ COMments ◄──┬─┘ └─ SYNtax ─────┘
Parameters
  • dmcl-name
    Identifies the DMCL with which the journal 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" earlier in this section.
  • journal-buffer-name
    Specifies the name of the journal buffer.
    Journal-buffer-name
    must be a 1- through 18-character name that follows the conventions described in 7.3, "Naming Conventions".
  • PAGE SIZE
    character-count
    Specifies the number of bytes in each page of the buffer. This clause is required on a CREATE statement. The buffer page size determines the block size for all disk or tape journal files defined in the DMCL.
    For VSAM disk journal files, the page size must match the rounded up CI size. IBM rounds up the specified CI size if the defined size is not a supported size. The journal buffer page size must match this rounded up size. The VSAM RECSZ should be 8 bytes less. CA IDMS automatically makes the internal journal block size 8 bytes less than the CI size.
    If a page is smaller than 256 bytes, then no data storage is possible. We recommend that a minimum page size of 512 bytes or larger be used.
    The value of
    character-count
    depends upon the operating system: 
System
Valid page sizes (in bytes)
z/OS and z/VSE
208 - 32764; multiple of 4. Page size cannot be greater than the maximum block size for the disk device.
z/VM
4096
  • BUFFER PAGES
    page-count
    Specifies the number of pages to be included in the buffer. This clause is required on a CREATE statement.
    Page-count
    must be an integer in the range 1 through 32,767.
  • DETails
    Displays or punches details about the journal buffer.
  • HIStory
    Displays or punches:
    • The user who defined the journal buffer
    • The user who last updated the journal buffer
    • The date the journal buffer was created
    • The date the journal buffer was last updated
  • ALL
    Displays or punches all information on the journal buffer. ALL is the default action for a DISPLAY or PUNCH verb.
  • NONe
    Displays or punches the name of the journal buffer.
Usage
Dropping the Journal Buffer
If you drop the journal buffer associated with a DMCL, be sure to define a new journal buffer before you regenerate the DMCL load module.
Examples
Defining a Journal Buffer
The following CREATE JOURNAL BUFFER statement defines the journal buffer JRNL_BUFF with 3 pages:
create journal buffer idmsdmcl.jrnl_buff page size 2932 characters buffer pages 3;
Modifying the Page Size of a Journal Buffer
The following ALTER BUFFER statement changes the page size of journal buffer JRNL_BUFF to 4,352 characters:
alter journal buffer idmsdmcl.jrnl_buff page size 4352 characters;
Dropping a Journal Buffer
The following DROP JOURNAL BUFFER statement deletes the definition of journal buffer JRNL_BUFF from the dictionary:
drop journal buffer idmsdmcl.jrnl_buff;