× The internal search function is temporarily non-functional. The current search engine is no longer viable and we are researching alternatives.
As a stop gap measure, we are using Google's custom search engine service.
If you know of an easy to use, open source, search engine ... please contact support@midrange.com.


  1.  Home
  2. MIDRANGE-L
  3. May 2014

Re: ?s regarding sparse indexes

And one of those sparse indexes might be a SELECT/OMIT LF, which are now considered as candidates for optimization - this is because the default in QAQQINI for IGNORE_DERIVED_INDEX is now *NO.

Vern

On 5/1/2014 2:21 PM, Nathan Andelin wrote:
Here's a quote from the Information Center:

"You can use the SQL CREATE INDEX statement to create a sparse index using
SQL selection predicates.

Last release users were given the ability to use the SQL CREATE INDEX statement
to create a sparse index using a WHERE condition. With this support, the
query optimizer recognizes and considers sparse indexes during its
optimization. If the query WHERE selection is a subset of thesparse index WHERE
selection, then the sparse index is used to implement the query. Use of the
sparse index usually results in improved performance."

So you can reference "tables" in SQL select statements, but under the
covers the query optimizer may use the sparse index.


As an Amazon Associate we earn from qualifying purchases.

This thread ...
Replies:
Follow On AppleNews
Return to Archive home page | Return to MIDRANGE.COM home page

This mailing list archive is Copyright 1997-2024 by midrange.com and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available on our policy page. If you have questions about this, please contact [javascript protected email address].

Operating expenses for this site are earned using the Amazon Associate program and Google Adsense.