2.2.6 Operands related to full recovery processing

25) pd_max_recover_process = concurrently-executable-full-recovery-processes-count
~<unsigned integer>((1-10))<<3>>
Specifies the number of processes to be recovered (REDO processes) during full recovery processing. For a HiRDB parallel server configuration, this operand specifies the number of processes to be recovered (REDO processes) per server (dictionary server or back-end server).
Condition
Parallel input/output processing is not performed for regular files.
Specification guidelines
  • The value to be specified depends on the file type:
    ConditionSpecification guideline
    Character special filesThere are at least 10 character special files (per server) that define RDAREAs10
    There are fewer than 10 character special files (per server) that define RDAREAsNumber of character special files
    Regular file1
  • Increasing the value of this operand increases the input/output concurrency during full recovery processing, and thus can shorten the recovery time. However, because a number of processes equaling value of this operand[Figure] server count are started, determine a value by taking the aforementioned specification value guideline and HiRDB resources into consideration.
26) pd_redo_allpage_put = Y | N
Specifies whether to output to a database the pages that were updated after a synchronization point during full recovery processing.
Y:
During full recovery processing, all pages updated after a synchronization point are output.
N:
During full recovery processing, only those pages that were not output to the database when an error occurred are output.
Specification guidelines
Normally, there is no need to specify this operand.
When a database is mirrored using LVM (Logical Volume Manager) mirroring facility, the original and duplicate of the mirror might not match each other if an OS or machine error occurs or if a unit error results in system switchover. In this case, to synchronize the original and duplicate volumes:
  1. First use LVM facility to synchronize the original and duplicate volumes, and then restart HiRDB.
  2. If you cannot use the above method to synchronize the original and duplicate volumes, or if the synchronization operation takes too long to satisfy the system requirements such as the system switchover time, specify Y for this operand. During full recovery processing at the restart of HiRDB following an error, all pages that were updated after a synchronization point are output to a database. In this process, HiRDB synchronizes the original and duplicate volumes, eliminating the mismatch between the original and duplicate mirrors.
For the action to take when a mismatch occurs between the original and duplicate mirrors, see the HiRDB Version 9 System Operation Guide.
Notes
  • When Y is specified for this operand, there is overhead for outputting all pages to the database during full recovery processing.
  • When this operand is specified, the message KFPH24004-I is output when the full recovery processing is finished. No message is output if this operand is omitted.