15.5.1 Before changing the RDAREA opening trigger attribute

Organization of this subsection
(1) RDAREA opening trigger attribute
(2) Criteria
(3) RDAREAs whose opening trigger attribute can be changed
(4) Notes

(1) RDAREA opening trigger attribute

The RDAREA opening trigger attribute refers to the time at which RDAREA open processing is executed by HiRDB.

Normally, RDAREA open processing is executed during HiRDB startup. However, as the number of RDAREAs increases, the amount of time required for HiRDB startup processing also increases. Instead, RDAREAs can be opened when they are accessed, rather than being opened during HiRDB startup processing. Thus, the RDAREA opening trigger attribute is changed. There are three triggers for opening an RDAREA, as shown in Table 15-1.

Table 15-1 RDAREA opening trigger attributes

TriggerInitial statusOpening timeClosing timeAdvantagesDisadvantages
INITIALOpen
  • During HiRDB startup
  • During pdopen command execution
During pdclose command executionHigh-speed execution from the first SQLMore time is required to start the system.
DEFERClosed
  • First time RDAREA is accessed
  • During pdopen command execution
During pdclose command execution
  • High-speed system startup
  • High-speed processing of SQLs after the first access
More time is required to access the RDAREA for the first time.
SCHEDULEClosed
  • First time RDAREA is accessed within a transaction
  • During pdopen command execution
  • During transaction termination
  • During pdclose command execution
  • High-speed system startup
  • Fewer open files (for DVD-RAM library devices)
More time is required to access the RDAREA for the first time by each transaction.

(2) Criteria

Initially, the RDAREA opening trigger is INITIAL. We recommend you consider changing the RDAREA opening trigger in the following cases:

Table 15-2 shows the operating procedure appropriate to each trigger.

Table 15-2 Operating procedure appropriate to each trigger

TriggerAppropriate operating procedure
INITIALHiRDB file system area is opened and the RDAREA information is made resident in memory during system startup. When an RDAREA is accessed for the first time, it is also opened in that process. In this case, the RDAREA information is not re-created; therefore, high-speed operation can be achieved from the first SQL.
The initial status of RDAREAs is to be opened during system startup. This status does not change unless an operation command is entered, except for a status change to error shutdown.
This trigger should be used when no special operating procedure is employed.
When this trigger is used, a closed RDAREA cannot be accessed.
DEFERHiRDB file system area is opened and the RDAREA information is made resident in memory when an RDAREA is accessed for the first time, not during system start. High-speed operation can be achieved for the subsequent accesses, because no processing is required on the HiRDB file system area other than open processing.
The RDAREAs' initial status during system startup is closed. Each RDAREA is opened when it is accessed for the first time. The status of RDAREAs does not change thereafter unless an operation command is entered, except for a status change to error shutdown.
Specify this attribute when you wish to avoid situations in which many HiRDB file system areas are open concurrently or you wish to reduce the time required for HiRDB startup.
When HiRDB is restarted, any RDAREAs to be recovered are opened during recovery processing.
When this trigger is used, a closed RDAREA can be accessed.
SCHEDULEHiRDB file system area is opened and the RDAREA information is made resident in memory when an RDAREA is accessed for the first time within a transaction, without opening it during system startup. The HiRDB file system area is closed when the transaction terminates. The transaction processing workload increases because the open processing and all subsequent processing is executed the first time an RDAREA is accessed by each transaction.
The RDAREAs' initial status during system startup is closed. An RDAREA is open only while a transaction that accesses it is being processed. When the transaction terminates, all the RDAREAs opened by it are closed.
When the pdopen command is entered, an RDAREA can be kept in open status until it is placed in shutdown and closed status. Other operation commands can also be used to change the RDAREA status. When an error is detected, the RDAREA is placed in error shutdown status.
Specify this attribute when you wish to avoid situations in which many HiRDB file system areas are open concurrently or you wish to reduce the time required for HiRDB startup when a DVD-RAM library device is being used.
When HiRDB is restarted, any RDAREAs to be recovered are opened during recovery processing, and they are closed when recovery processing finishes.
When this trigger is used, a closed RDAREA can be accessed.

(3) RDAREAs whose opening trigger attribute can be changed

The opening trigger attribute can be changed for the following RDAREAs:

(4) Notes

  1. Before an RDAREA's opening trigger attribute is changed, it must be placed in shutdown and closed status with the pdhold -c command.
  2. Before an RDAREA whose opening trigger attribute has been changed can be used, it must be released from shutdown status and placed in open status by the pdrels -o command.
  3. The same opening trigger attribute should be set for all RDAREAs in a HiRDB file system area.
  4. RDAREAs are not open while the standby system unit to which the rapid system switchover facility switches is in standby status. In addition, because the purpose of this facility is to minimize system switchover time, only those RDAREAs that are needed for recovery when a system is switched over are opened, while the other RDAREAs remain closed. Therefore, the RDAREA opening trigger on a standby system is not the INITIAL attribute. RDAREAs set with the INITIAL attribute are changed to the DEFER attribute.
  5. Because the purpose of the standbyless system switchover facility is to minimize system switchover time, this facility opens only those RDAREAs that are needed for recovery when a system is switched over, while the other RDAREAs remain closed. Therefore, the opening trigger of the RDAREAs on the alternate BES or the alternate portion is as follows:
    [Figure]When system switchover occurs, the opening trigger for RDAREAs in the alternate portion is the SCHEDULE attribute.
    [Figure]When returning the system to the normal BES after having recovered from the error, the opening trigger for RDAREAs set with the INITIAL or DEFER attribute is the DEFER attribute. The opening trigger for RDAREAs set with the SCHEDULE attribute remains unchanged.
  6. Table 15-3 indicates the accessibility of UAP RDAREAs according to the open attribute.

    Table 15-3 Accessibility of UAP RDAREAs according to the open attribute

    Opening trigger for RDAREAStatus of RDAREARDAREA accessible?
    INITIALNot shutdownOpenYes
    ClosedNo
    Command shutdownOpenNo
    ClosedNo
    Reference-possible holdOpenSome1
    ClosedNo
    Reference-possible backup holdOpenSome1
    Updatable backup holdOpenYes
    Error shutdownOpenNo
    ClosedNo
    No-log holdOpenSome2
    ClosedNo
    Initialization holdOpenNo3
    ClosedNo3
    Online reorganization holdOpenSome4
    ClosedSome4
    DEFER or SCHEDULENot shutdownOpenYes
    ClosedYes
    Command shutdownOpenNo
    ClosedNo
    Reference-possible holdOpenSome1
    ClosedSome1
    Reference-possible backup holdOpenSome1
    ClosedNo
    Updatable backup holdOpenNo
    ClosedYes
    Error shutdownOpenNo
    ClosedNo
    No-log holdOpenSome2
    ClosedSome2
    Initialization holdOpenNo3
    ClosedNo3
    Online reorganization holdOpenSome4
    ClosedSome4
Legend:
Yes: Accessible
Some: Some SQL code accessible
No: Not accessible
1 Only reference SQL can be accessed.
2 Only PURGE TABLE can be executed.
3 Placed in lock-release wait status
4 Other than the following, only SQL statements that access a current RDAREA while in the log acquisition mode can be executed:
  • CREATE TABLE
  • CREATE INDEX
  • DROP TABLE
  • DROP INDEX
  • DROP SCHEMA
  • ALTER TABLE
  • PURGE TABLE
  • LOCK