Restricting read and write access to the active data set

To restrict read and write access to the active historical data set at the end of the interval, issue the Q line command.

Related topic

Managing-the-historical-database

After the Q line command is issued, you can neither write to nor read from the active data set and you must wait until the end of the current interval for command processing to be completed.

The Q line command can be used against a historical data set that has a Status field value of Active only; it has no effect on data sets with another status.

When the Q line command is issued against the active data set, the Pending field value changes to QUIESCED. Recording to or reading from the active quiesced data set is prohibited immediately.

When the current interval ends, the results are as follows:

The historical recorder switches recording to the next available data set and writes the record for the interval that just ended.
The Status field changes to Active for the new data set.
The Status field changes to Qscd for the previously active data set and the Pending field retains a QUIESCED value.

Important

The previously active data set retains a QUIESCED pending state throughout the duration of the new interval. Data cannot be written to or read from this data set from the time the Q line command is issued until the end of the new interval.

At the end of the new interval, the QUIESCED pending state automatically ends and the Pending field value changes to a Qscd status. A quiesced data set must be manually unquiesced to become eligible for recording or reading again. Issue the U line command to unquiesce a quiesced data set; see Reinstating-read-and-write-access-to-a-quiesced-data-set.

The following figure shows how to issue the Q line command against the active data set to force the historical recorder to switch recording to the next available data set at the end of the current interval.

Using the Q line command to restrict read/write access

ddmmmyyyy hh:mm:ss ------ BMC AMI Ops WINDOW INTERFACE (Vv.r.mm) ----------
COMMAND ===>                                               SCROLL ===> PAGE
CURR WIN ===> 1        ALT WIN ===>
>W1 =DSLIST===========SYSB=====*=======dd/mm/yyyy=hh:mm:ss====MVMVS==D=====3
C DDNAME   From Date Time To Date    Time Rec Status Pending Data set nam
- ------   ---------- ----- --------- ----- --- ------ ------- ------------
q HISTDS03 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm Yes Active ****** PROD1.IMAGSY
  HISTDS01 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm Yes Closed ****** PROD1.IMAGSY
  HISTDS02 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm No Closed ****** PROD1.IMAGSY

The following figure shows how the Pending field changes when you issue the Q line command.

Pending field change for a quiesced data set

   ddmmmyyyy hh:mm:ss ----- BMC AMI Ops WINDOW INTERFACE (Vv.r.mm) --------
COMMAND ===>                                               SCROLL ===> PAGE
CURR WIN ===> 1        ALT WIN ===>
>W1 =DSLIST===========SYSB=====*=======dd/mm/yyyy=hh:mm:ss====MVMVS==D=====3
C DDNAME   From Date Time To Date    Time Rec Status Pending   Data set n
- ------   ---------- ----- --------- ----- --- ------ ------   ----------
  HISTDS03 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm Yes Active QUIESCED PROD1.IMAG
  HISTDS01 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm Yes Closed ******    PROD1.IMAG
  HISTDS02 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm No Closed ******    PROD1.IMAG

The following figure shows how the Status field changes at the end of the current interval.

Status field changes resulting from Q line command

ddmmmyyyy hh:mm:ss ------ BMC AMI Ops WINDOW INTERFACE (Vv.r.mm) ---------
COMMAND ===>                                               SCROLL ===> PAGE
CURR WIN ===> 1        ALT WIN ===>
>W1 =DSLIST===========SYSB=====*=======dd/mm/yyyy=hh:mm:ss====MVMVS==D=====3
C DDNAME   From Date Time To Date    Time Rec Status Pending   Data set n
- ------   ---------- ----- --------- ----- --- ------ -------   ----------
  HISTDS01 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm Yes Active ******    PROD1.IMAG
  HISTDS03 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm Yes Qscd   QUIESCED PROD1.IMAG
  HISTDS02 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm No Closed ******    PROD1.IMAG

Even though the HISTDS02 data set has older data than the HISTDS01 data set, the HISTDS01 data set becomes the Active data set because it has a Rec field value of Yes. The HISTDS02 has a Rec field value of No, so it is not eligible to have data written to it; see Changing-recording-eligibility for more information.

The following figure shows how the Pending field changes at the end of the new interval.

Pending field change at the end of the new interval

   ddmmmyyyy hh:mm:ss ------ BMC AMI Ops WINDOW INTERFACE (Vv.r.mm) -------
COMMAND ===>                                               SCROLL ===> PAGE
CURR WIN ===> 1        ALT WIN ===>
>W1 =DSLIST===========SYSB=====*=======dd/mm/yyyy=hh:mm:ss====MVMVS==D=====3
C DDNAME   From Date Time To Date    Time Rec Status Pending   Data set n
- ------   ---------- ----- --------- ----- --- ------ -------   ----------
  HISTDS01 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm Yes Active ******** PROD1.IMAG
  HISTDS03 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm Yes Qscd   ******** PROD1.IMAG
  HISTDS02 dd/mm/yyyy hh:mm dd/mm/yyyy hh:mm No Closed ******** PROD1.IMAG

Restricting read and write access to the active data set

On this page