Progress
Database Administration
Guide and Reference


Creating After-image Areas

Follow these steps to create AI areas:

  1. Create the structure description file for the database. See "Creating and Deleting Databases," for a complete description of how to create a structure description file.
  2. Define the data extents.
  3. Define any BI extents.
  4. Define any fixed-length AI extents. You must define four tokens in the file description line. Table 11–1 describes each token and what you have to enter for fixed-length files.
  5. Table 11–1: File Tokens 
    Token
    Description
    First
    Specifies the file type. Type a to indicate that this extent is an AI extent.
    Second
    Specifies the extent file pathname. Enter a pathname that represents a standard operating system file. If you do not supply an extension, the database engine automatically appends a .an extension.
    Third
    Specifies whether the extent is a fixed-length or variable-length extent. Type f for a fixed-length extent. It must be lowercase.
    Fourth
    Specifies the length of the extent in 1,024-byte (1K) units. The minimum length for a fixed-length extent is 16K. The extent length must be a multiple of 16K for all operating systems. If you specify any other size, PROSTRCT displays a warning message and rounds the size up to the next multiple of 16K. The maximum length of an extent depends on the size of the file system and/or physical volume that contains the extent.

    The following example shows a fixed-length after-image extent definition:

    a    db/mary/apdir/test.a1 f 2048 
    

  6. Define any variable-length after-image extents. You only have to specify the first two tokens: the extent type and pathname. Unlike data or BI extents, you can define more than one variable-length after-image extent for a single database.
  7. Create the empty database structure using the PROSTRCT utility. For more information about the structure description file and the PROSTRCT and PROCOPY utilities, see Maintaining Database Structure."
  8. Create the initial database contents using the PROCOPY or PROREST utility. For more information about the PROCOPY and PROREST utilities, see Database Administration Utilities."

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