Re: EVIs

["David Morris" <dmorris@xxxxxxxxxxxxx>]

Debbie,

Optimizing SQL access for large files requires testing.  Even if you applied 
of the knowledge contained in the optimization chapter of the SQL guide, you 
can't be sure how the optimizer will behave until you test.  I have found that 
EVIs typically improve performance by about 10-30% in a limited set of 
circumstances. That is great, especially when you are working with large 
sets of data like that used in a data warehousing environment.  When you 
get a statement to use a regular index, the improvement can be much greater.

David Morris

>>> Debbie.Moore@RCIS-NET.COM 03/01/01 01:31PM >>>
I am looking for information on Encoded Vector Indexes.  Supposedly these
are useful in data warehouse type situations where the tables are large and
there are a relatively small number a distinct key values in the table.  
The problem was that we removed the LFs and created the EVI.  Then when
running a RUNSQLSTM or using our Data Warehouse Query Tool,  the vector
index did not get used.  Instead the ODP was created during the run, causing
it to be dreadfully sluggish.
Any ideas on what can be done for this?

Debbie Moore
* * * * *
     2249


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