Skip to main content
Delphix

SnapSync May Fail for Oracle DBs with Large SCNs (TB004)

Alert Type

Data Availability

Impact

A Delphix SnapSync job may complete normally and without errors. But attempts to provision or refresh from the resulting snapshot may fail because Snapshot SCN is calculated incorrectly.  

Contributing Factors

The issue occurs in the following Delphix Releases:

  • Delphix Engine 3.1.4.0, 3.1.5.0
  • Delphix Engine 3.2.0.0 
  • Delphix Engine 3.2.1.0

The issue can occur when provisioning Oracle VDBs from snapshots that were generated on one of the affected Delphix Releases above and which have a checkpoint SCN larger than 4,294,967,295.

Snapshot cards in the Delphix GUI show the Snapshot SCN, which is always greater than or equal to the checkpoint SCN.  If the displayed Snapshot SCN is less than 4,294,967,295, then the related snapshot cannot be affected by this problem. 

Symptoms

Provision jobs may fail, and errors in the VDB alert log may include:

ORA-01547: warning: RECOVER succeeded by OPEN RESETLOGS would get error below
ORA-01194: file <n> needs more recovery to be consistent
ORA-01110: data file <path>

or

ORA-279 signalled during: alter database recover database noparallel until cancel using backup controlfile...

Relief/Workaround

By default, each Oracle snapshot card shows only the Snapshot SCN.  However, by activating the Slide to Provision by SCN slide, the SCN Range for each snapshot will be displayed.  A workaround is to increment the Selected SCN to the high end of the SCN Range, and then provision. 

Resolution

The issue is addressed in Delphix Engine 3.1.5.1, Delphix Engine 3.2.2.0, and later releases.  Once upgraded to a Delphix release containing the resolution, further snapshots will not be impacted.