ORA-00059: Maximum Number of DB_Files Exceeded

by | May 20, 2025 | Blog, Oracle

ORA-00059 Maximum number of DB_Files Exceeded

The ORA-00059 error can occur if you don’t check the DB_FILES parameter before creating or cloning new PDBs in your CDB.

Here are the steps to fix CDB when this error occurs. You can also proactively add this to your cloning Documentation to prevent the error from happening.

Note: Downtime is required to change this parameter.

Steps to Check if Change is Required for ORA-00059

  1. Log into sqlplus to the CDB
  2. Show parameter DB_FILES
  3. Get the total current number of db files used
    • select count(*) as Total_DB_FILES from cdb_data_files;
  4. Get the number per PDB to see the number of datafiles added per PDB
    • select con_id, count(*) from cdb_data_files group by con_id;
  5. Compare Values between DB_FILES and Total_DB_FILES 
  6. If the number of new data files in PDB, from step 4, is greater than the difference between DB_FILES and Total_DB_FILES, then you need to increase the DB_FILES Parameter value.

Example:

DB_FILES = 200
Total_DB_Files = 180
Datafiles from new PDB = 30

                                   200-180 = 20  < 30    Need to increase DB_FILES

Steps to Increase DB_FILES Parameter Value

  1. Alter SYSTEM set DB_FILES={new value} scope = spfile;
  2. Bounce CDB and PDBs
    • alter pluggable database all close immediately;
    • shutdown immediate
    • startup
    • alter pluggable database all open;
  3. Confirm change
    • Show parameter DB_FILES

Conclusion

Be proactive to avoid this error when possible. Either way, these steps will help you quickly fix your DB_FILES parameter when you encounter the ORA-00059 error.

Because downtime is required to modify this parameter, ensure you follow your change control processes and avoid impacting customers or internal stakeholders.

Need help managing Oracle CDBs, PDBs, or resolving errors like ORA-00059?

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