"SET ROLE" Under High Concurrency Causes More "latch: row cache objects" and Slower Response Times

(Doc ID 2310611.1)

Last updated on SEPTEMBER 29, 2017

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.4 to 12.1.0.2 [Release 11.2 to 12.1]
Information in this document applies to any platform.

Symptoms

"SET ROLE" under high concurrency causes more "latch: row cache objects" and which is leading to delay in user response time. After further testing found that starting 11.2.0.4, "SET ROLE" statement is performing slow.

Installing patch for known Bug 23575520 and increasing SGA doesn't help.

If we just execute the same "SET ROLE" statement in single session, then no issues.

From testing with 300 concurrent sessions executing SET ROLE statement with 100 roles (roles are empty with no privileges granted to them) listed in it takes following time across various
versions, starting 11.2.0.4 we see high number of 'latch: row cache objects':

Version              Time (10046 Trace)
--------------       -------------------
11.2.0.3                17.11 Sec
11.2.0.4                85.33 Sec
12.1.0.2                84.26 Sec

 

Changes

 Upgrading database from 11.2.0.3 to 12.1.0.2.

Cause

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