Using Case Insensitive Searches and Setting NLS_SORT to Anything Other than BINARY (e.g. BINARY_CI) with NLS_COMP set to ANSI or LINGUISTIC Causes Full Table Scans Instead of Using Indexes (Doc ID 2008186.1)

Last updated on AUGUST 04, 2018

Applies to:

Oracle Database - Enterprise Edition - Version 11.1.0.6 and later
Information in this document applies to any platform.

Queries are performing more slowly following the introduction of case insensitive searches (in this case using NLS_SORT=BINARY_CI) in the database
With NLS_SORT set to anything other than BINARY (here NLS_SORT=BINARY_CI), queries are perform full table scans and ignore index based searches.
NLS_COMP is set to ANSI or LINGUISTIC

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