Physical restore

When the archecker utility performs a physical restore, the utility extracts data from a level-0 archive.

When performing a physical restore, archecker performs the following tasks:
  • Disables all constraints (including foreign constraints that reference the target table), indexes, and triggers until the data is restored. Restore performance is better if the table has no constraints, indexes, or triggers.
  • Reads the schema command file to determine the following:
    • The source tables
    • The destination tables
    • The schema of all tables
    • The dbspace names of where tables are located
    • The specific archive to extract data from
  • Scans the archive for pages belonging to the tables being restored
  • Processes each row from the data page and determines if the row is complete or partial.

    If the row is a partial row, then archecker determines if the remaining portion of the row has been staged, and if not, it stages the row for later processing.

  • For a physical-only restore, applies filters to the row and rejects rows that are not required.
  • Inserts the row into the destination table.

To restore a table with the original schema, the source schema must be specified. To restore a table with a different schema, the table name in the target schema must be different from the table name in the source schema. After restoring by using a different schema, the table can be renamed with the rename table statement.