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Delphix

Oracle virtual database (VDB) Provisioning performance degrades due to added data files

Issue

Virtual Database (VDB) provisioning may take longer than expected when recovery includes adding new datafiles. 

Troubleshooting

Confirmation that recovery includes adding new datafiles can be seen by monitoring for "ORA-01244" events in the Oracle Alert Log during provisioning of the VDB.

An example of this can be seen below. 

ORA-00283: recovery session canceled due to errors
ORA-01244: unnamed datafile(s) added to control file by media recovery
ORA-01110: data file 2: '/u01/app/oracle/oradata/NEWMAN/datafile/o1_mf_t_d0cxn449_.dbf'

The Delphix Engine will detect the recovery failure and resolve it by creating the new datafile. This creation may take some time depending on the size of the datafile.

ORA-1112 signalled during: alter database recover cancel...
Tue Oct 18 03:27:20 2016
alter database create datafile 2 as new
Completed: alter database create datafile 2 as new

The Delphix Engine will then continue recovery. If recovery encounters another new datafile, the process will repeat.

Resolution

To avoid this situation ensure a fresh SnapSync is taken as soon as possible after large datafiles are added to the dSource database. This will allow the starting provisioning point to include the new datafiles, avoiding the need to create and recover through these operations.