SQL Performance Degrades After an to Upgrade to 12c For SQL that Relies on Histograms for Selectivity Estimates
(Doc ID 2240535.1)
Last updated on FEBRUARY 03, 2019
Oracle Database - Enterprise Edition - Version 126.96.36.199 and later
Information in this document applies to any platform.
- Single or multiple SQL statements using incorrect indexes
- Upgraded the database to 12c
- Histograms are present and used by the optimizer for selectivity estimates
- Diagnostics how wrong selectivity estimates for character columns which have histograms before upgrade
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