Query Against DBA_EXTENTS Performs Slowly After Upgrade to

(Doc ID 1453425.1)

Last updated on MAY 23, 2017

Applies to:

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


Queries on DBA_EXTENTS are much slower due to the presence of a merge join cartesian.
This can also influence the performance of script used to collect upgrade/migrate diagnostics as per instructions in:

<Document 556610.1> Script to Collect DB Upgrade/Migrate Diagnostic Information (dbupgdiag.sql) .

Running script  on version prior to upgrade, there was no performance issue.
The following SQL query from dbupgdiag.sql may run slowly  (~2 hours) after applying patchset



An execution plan regression occurs if there are a large number of records in the X$KTFBUE table.  Gathering of dictionary or fixed object stats does not improve performance as this table is intentionally omitted from those packages.


Sign In with your My Oracle Support account

Don't have a My Oracle Support account? Click to get started

My Oracle Support provides customers with access to over a
Million Knowledge Articles and hundreds of Community platforms