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After Mview Logs Creation, There is A Lot Of 'Dfs Lock Handle' Waits On DML (Doc ID 845886.1)

Last updated on FEBRUARY 17, 2019

Applies to:

Oracle Database - Enterprise Edition - Version 10.2.0.3 to 10.2.0.4 [Release 10.2]
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.

Symptoms

After creating materialized view logs on two very active tables, many sessions doing DML on those base tables were showing 'DFS LockHandle' waits.

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  1. Trace files, generated by a system state dump, show a reference to a sequence.
    KGL Sequence Object #<OBJ_ID>: 
  2. A query of dba_objects for object_id <OBJ_ID> determined this is object SYS.CDC_RSID_SEQ$, which is the same sequence used to insert data into some of the mview logs tables :

    INSERT /*+ IDX(0) */ INTO "<USER_NAME>"."MLOG$_BASETABLE" (dmltype$$,old_new$$, snaptime$$
    ,change_vector$$,sequence$$,m_row$$,"COL1","UID","STATUS" ,"ID","PFUID") VALUES
    (:d,:o,to_date('4000-01-01:00:00:00','YYYY-MM-DD:HH24:MI:SS'),:c
    ,sys.cdc_rsid_seq$.nextval,:m,:1,:2,:3,:4,:5)

Changes

 

Cause

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In this Document
Symptoms
Changes
Cause
Solution
References

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