PROBLEM:

We have received below error in the alert log.

2017-12-07 08:01:24.890000 +03:00
Errors in file /oradbtrace/diag/rdbms/prodid2/trace/prodid2_m001_3322.trc:
ORA-12850: Could not allocate slaves on all specified instances: 2 needed, 0 allocated

ANALYSIS AND SOLUTION:

Lets check the trace file /oradbtrace/diag/rdbms/prodid2/trace/prodid2_m001_3322.trc.

In the trace the ACTION NAME:(Automatic Report Flush)

Automatic report capturing is a new feature in oracle 12c, As part of this feature, some monitoring SQLs are executed by MMON_SLAVE to identify the resource-intensive SQLs queries. And this monitoring SQLs while executing sometimes fail and this type of error will be logged in the alert log.

Oracle already acknowledged this bug.

 

However, to fix this the workaround is to set parameter And this doesn’t need database bounce.

After setting this parameter, this type of error will be suppressed.