Logical files can share access paths. This is also true, as I recall, of
indexes, which are a special kind of logical file.
Indexes do have a potential performance benefit - they can have larger
pages brought into memory at one time. But LFs work just fine, although
some recommend indexes when used only for optimization.
Create the index with both key fields first, then the one with only
FieldA. And remember that to share, they have to start with the same
columns.
I know I'm missing some details, but I hope this gets you started. Try
creating the indexes and see if the second one says it is sharing the
access path - look at DSPFD.
Let me see, maybe if you create the longer index first and an SQL index,
then create the logical with the single field, it'll share the advantage
of the index' access path - it's been too long!!!
Back to work!
Vern
On 3/4/2013 1:55 PM, Stone, Joel wrote:
What columns should I review when determining which indexes to add to a database?
- Times Advised for Query Use
- Most Expensive Query Estimate
- Others?
If one row advises to add FieldA , FieldB, and a second row advises FieldA for the same file, would adding a logical file with keys FieldA & FieldB do the trick for both advising rows?
Does creating a LF benefit the same as adding an index?
Thanks
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