enq: MS - Contention During Materialized View Refresh

(Doc ID 2366181.1)

Last updated on MARCH 05, 2018

Applies to:

Oracle Database - Enterprise Edition - Version 12.1.0.2 and later
Information in this document applies to any platform.

Symptoms

enq:MS - contention is seen during MV refresh, even though there is no MV log. The MV is doing complete refresh.

During refresh, application sessions experience enq: MS - contention when accessing the base objects of the materialized views, and this sometimes lasts long enough that it times out the session (from the application side).

Changes

When an mview refresh operation takes place, one of the things that happen is: SYS.SNAP$ and SYS.MLOG$ are updated to show the time of refresh.

Cause

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