| Title: | DEC RdbExpert for OpenVMS |
| Notice: | RdbExpert V2.1A is now available - See note 2.4 |
| Moderator: | OOTOOL::CRAIG |
| Created: | Fri Jul 10 1992 |
| Last Modified: | Tue Jun 03 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 755 |
| Total number of notes: | 2761 |
For most common uses of Expert is there really much benefit to
using /options=column_volume in an rmu/extract/items=volume to
create the volume PDL file ? Generally I find it hard to believe
that there would be much difference in the analysis versus a
/options=normal.
Regards,
rcs
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 734.1 | Better data access recommendations are achieved with the additional information | OOTOOL::CRAIG | Fri Mar 14 1997 13:54 | 20 | |
Hi Richard, Good question. Looking at the differences in the output between the RMU/EXTRACT/options=normal/items=volume and RMU/EXTRACT/options=column_volume/items=volume the output from /options=normal gives only table cardinalities. Using the /options =column_volume the column cardinalities are also included. Expert does a better job making index recommendations knowing the column cardinalities. The column cardinalities influence the ordering of the segments that Expert will recommend. Good index recommendations can make a big difference in database performance, so I'd say that it's a good idea to use the /options=column_volume. Take care, Sheri | |||||