Hello All, I have a sort of about 4GB, 15M records of variable length. For some reason DFSORT chooses not to use dataspace/hiperspace or memory objects for this sort for no obvious reason; Parameters are all set corrects (EXPMAX, RES, OLD and HIPRMAX and so on). The system is not paging at all. Only thing not tuned for this SORT (as far as I can see) is that it does not know the AVGRLEN in advance, and wrongly calculated the number of expected records in the SORTIN (it expects 350k instead of 15m, based on the SORTIN LRECL). So, DFSORT volunteered not to use Hipersorting. Looking for answers I found this excerpt from DFSORT Tuning Guide on Hipersorting: When Hipersorting cannot be used, DFSORT uses disk work data sets to store its intermediate data, which is referred to as disk-only mode. Note that Hiperspace-only mode usually provides the best performance when compared to Hiperspace-mixed and disk-only modes. However, this is not always true for Hiperspace-mixed mode when compared to disk-only mode. Due to the additional Hiperspace overhead, the use of disk-only rather than Hiperspace-mixed mode can at times be more advantageous in terms of performance, and therefore DFSORT may choose not to use Hipersorting.
So, what are those "times"; what made DFSORT use disk-only mode? The file size (4GB)? The variable-length? The wrong records number? Any ideas would be appriciated, Yifat ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
