Values for the COMPATIBLE Initialization Parameter in Oracle Database

 Notes:

• The value of the COMPATIBLE parameter can be increased to a higher version, but it can never be decreased to a lower version.

• The value of the COMPATIBLE parameter should not be changed for a Release Update (RU) or Release Update Revision (RUR). For example, assume you are running Oracle Database 19c and the value of COMPATIBLE is 19.0.0. You then apply Oracle Database Release Update 19.6.0.0.0. Do not set the value of COMPATIBLE to 19.6.0; leave it set to 19.0.0.

• When using a standby database, this parameter must have the same value on both the primary and standby databases.

• When you set the value of the COMPATIBLE parameter to 12.2.0, the maximum size of SQL identifiers is increased from 30 bytes to 128 bytes.

When to Set the COMPATIBLE Initialization Parameter in Oracle Database

Oracle recommends increasing the COMPATIBLE parameter only after you have completed testing the upgraded database.

After the upgrade is complete, you can increase the setting of the COMPATIBLE initialization parameter to the maximum level for the new Oracle Database release. However, after you increase the COMPATIBLE parameter, you cannot subsequently downgrade the database.

Rules for COMPATIBLE Parameter Settings in Multitenant Architecture

The COMPATIBLE parameter of the container database (CDB) affects the COMPATIBLE parameter settings of pluggable databases (PDBs) plugged into that container database. Review the following scenarios that occur when you plug in a PDB to a CDB:

• PDB COMPATIBLE equal to CDB$ROOT COMPATIBLE parameter setting.

  Result: No change to the PDB COMPATIBLE parameter setting.

• PDB COMPATIBLE is lower than CDB$ROOT COMPATIBLE parameter setting.

  Result: The PDB COMPATIBLE parameter is increased automatically to the same COMPATIBLE parameter setting as CDB$ROOT. After you plug in the PDB, you cannot downgrade the PDB to an earlier release.

• PDB COMPATIBLE is higher than CDB$ROOT COMPATIBLE parameter setting.

  Result: The PDB cannot be plugged in. Only PDBs with a COMPATIBLE parameter setting equal to or lower than CDB$ROOT can be plugged in to the CDB.

Default and Minimum COMPATIBLE Parameter Values

The COMPATIBLE parameter should not be changed for an RU or an RUR, either for CDB or Non-CDB instances. The following table lists the default and minimum values for the COMPATIBLE parameter in Oracle Database 19c, compared to earlier releases supported for direct upgrade:

Table 1-2 The COMPATIBLE Initialization Parameter

Oracle Database Release	Default Value	Minimum Value
Oracle Database 19c	19.0.0	11.2.0
Oracle Database 12c Release 2 (12.2)	12.2.0	11.2.0
Oracle Database 12c Release 1 (12.1)	12.0.0	11.0.0
Oracle Database 11g Release 2 (11.2)	11.2.0	10.0.0