IRLM (sec.) 6.058 8.547 5.398 8.605 Total CPU  time (sec.) 48.579 69.442 45.717 67.624 About 4%  improvement with  this enhancement Total CPU  time (sec.) 48.579 69.442 45.717 67.624 About 4%  improvement with  this enhancement Usage considerations The removal of log force write for identity columns and XML DOCID columns in a Db2 12 data  sharing environment is automatically enabled when Db2 is at function level V12R1M100 and  greater. No special configuration is required to use this enhancement. Note:  This enhancement does not apply to sequences. 2.5 Range-partitioned table spaces with relative page  numbering  Before Db2 12, the maximum partition size is limited to 256 GB. In cases when the partition  size is 256 GB, a maximum of 64 partitions is allowable for table spaces that use a 4 K page  size. Although the maximum number of partitions is 4096, the actual maximum number of  partitions a table can have is determined by its partition size and its page size. This limitation  exists because pages are numbered sequentially at the table space level and the partition  number of a data page is implicitly imbedded in the first  n  bits (where  n  depends on the  number of partitions) of its page number. In Db2 12, a new type of partition-by-range universal table space is introduced. This new type  of range-partitioned table space uses relative page numbering where the page numbers start  from zero at the partition level. Pages are no longer absolute page numbers in the table  space. This new type of table space is called Partition-By-Range - Relative Page Numbering  (PBR RPN).  PBR RPN table spaces can have a maximum partition size of 1 TB. The maximum number of  partitions continues to be up to 4096 partitions, which means the maximum size of a PBR  RPN table space is 4 Petabytes (4 PB) with 4096 partitions. The number of partitions is no  longer dependent on the partition size. PBR RPN table spaces also allow certain attributes,  such as DSSIZE, to be specified at the partition level instead of the table space level.  To enable this partition-independent page numbering, the size of a Record ID (RID) is  expanded to 7 bytes. Internally, Db2 always uses the new 7-byte RIDs. As a result, longer log  records are created in Db2 12, regardless of whether PBR RPN table spaces are used. Log  records that are related to table spaces and indexes increase by 20 bytes. Range-partitioned table spaces with relative page numbering can be created in Db2 12 at  function level V12R1M500 and beyond only. A new system parameter called  PAGESET_PAGENUM is also introduced by this enhancement. It controls whether page  numbering of newly created PBR table spaces is relative or absolute by default. The default  setting for the parameter is to use absolute page numbering (this setting is to have the same  behavior as in previous Db2 versions).  Chapter 2. Scalability enhancements and subsystem performance  63