Research And Application To The Reorg Utility In DB2 For Z/os

The re-organization technology (also called REORG technology in DB2) is the most particular technique in mainframe databases. Its function is to make the record sorted by the main index through several steps. And with the method of prefetch, DB2 ensures the effectiveness of running application programs.By considerable researches on this technology, this paper uses different setup of REORG parameters to obtain the most suitable usage in corresponding business system. Then, we provide a way on how to use the REORG technology instead of some DDL operations to modify the tables, which can reduce the affection on the successive business system.Furthermore, by studies on the DB2 Catalog tables, this paper shows the reason why the SQL execution plan sometimes gets worse and worse. Then based on these researches, a new method that can avoid the hidden troubles of the business system is presented by using the REORG technology. Finally, by making use of the mainframe programming language REXX, an auto-REORG tool is created to solve these problems, by which the data records are re-organized and the probability of getting worse and worse in the SQL executiong plan is reduced. Through these researches, this paper obtains the final object that the REORG technology is sufficiently realized in all kinds of corresponding systems. Furthermore, this technology on DB2 resolves the hidden problem as well as guarantees the continuity of running systems.