Common quiesce points

A common quiesce point is a point at which data is consistent across related table spaces as a result of running the QUIESCE utility. Although establishing such a quiesce point is not required for point-in-time recoveries, doing so can improve recovery time and ensure consistency for sets of related objects.

A quiesce point is not essential for point-in-time recoveries. Additional methods exist for ensuring that objects are recovered to a consistent state, without any uncommitted data. You can recover objects to any RBA or LRSN by using the TORBA or TOLOGPOINT options on the RECOVER utility statement. In this case, RECOVER automatically handles any uncommitted units of work to ensure that the data is left in a consistent state. You can also recover to an image copy that was taken with SHRLEVEL REFERENCE. This image copy serves as a point of consistency.

However, recovering objects to a quiesce point can be faster than recovering to any RBA or LRSN, because no work has to be backed out. Also, you might want to establish quiesce points for related sets of objects if you need to plan for point-in-time recovery for the entire set. For point-in-time recoveries, all objects in a table space set need to be recovered to the same point in time.

To obtain a common quiesce point for related table spaces, use the QUIESCE utility with the TABLESPACESET option. For the purposes of the QUIESCE utility, a table space set includes the following sets for objects:

  • A group of table spaces that have a referential relationship
  • A base table space with all of its LOB table spaces
  • A base table space with all of its XML table spaces
  • Start of changeA table space with a system-period temporal table and the table space with the related history tableEnd of change

If you use QUIESCE TABLESPACE instead and do not include every member of the table space set, you might have problems when you run RECOVER on table spaces in the set. RECOVER checks if a complete table space set is recovered to a single point in time. If the complete table space set is not recovered to a single point in time, RECOVER places all dependent table spaces in CHECK-pending (CHKP) status.

When you use QUIESCE WRITE YES on a table space, the utility records the quiesce point in SYSIBM.SYSCOPY. QUIESCE inserts a SYSCOPY row that specifies ICTYPE='Q' for each related index that is defined with COPY=YES.