Selectively specifying UOWs for reorganization

SELECT_UOW=(IOVF, n1 ) selects UOWs based on a minimum specified number of IOVF control intervals (CIs) used. When this value is selected and you specify a numeric value for n1, the reorganization function will identify and reorganize only UOWs that have used at least that many IOVF CIs. This value can be used to exclude UOWs from the reorganization that have used a minimum amount of IOVF based on your assessment of CI usage. An example is shown in Sample control statements for selective UOW reorganization based on minimum CIs used. For databasedbdname, the reorganization function considers UOWs for reorganization in areaareaname only if the UOW has used at least five IOVF CIs.

SELECT_UOW=(IOVF,n1,n2) selects UOWs based on a minimum and maximum specified number of IOVF control intervals (CIs) used. When this value is selected and you specify a numeric value for n1 and n2, the reorganization function will identify and reorganize only UOWs that have used at least the minimum (n1), and no more than the maximum (n2) number of IOVF CIs. This value can be used to exclude UOWs from the reorganization that have used a minimum and maximum amount of IOVFs based on your assessment of CI usage. SELECT_UOW=(IOVF,n1,n2) also allocates and limits the number of buffers used by the online reorganization function to a maximum value for n2. This feature restricts the amount of ECSA used by the online reorganization function.

Either of the preceding values for the SELECT_UOW keyword can be combined with additional keywords to further limit UOW selection criteria.

The FRAGMENTATION_PERCENT keyword is used to specify the percentage of disorganization that must be detected in a UOW that extends into IOVF to qualify the UOW for reorganization.

An example of the FRAGMENTATION_PERCENT keyword is shown in the following figure, For DBD dbdname, the command set reorganizes UOWs in areas areanam1 and areanam2 if the UOW extends into IOVF and the minimum user-specified percentage of fragmentation (2 percent) is detected. Reasonable fragmentation percentage values range from 1 to 5 percent. Fragmentation greater than 5 percent is unlikely under ordinary circumstances.

The IOVF_SAVE_THRESHOLD keyword specifies the minimum amount of IOVF that must be saved before the UOW is selected for reorganization. The amount can be specified as the number of CIs or as a percentage of the IOVF that is used by the UOW. The following figure specifies that UOWs will not be reorganized unless five or more IOVF CIs are released.

The following code specifies that UOWs will not be reorganized unless 10 percent or more of the IOVF control intervals that are allocated to the UOW are released.