Container Tablespaces- Tablespaces and Data Files
Now with 23c it might make even more sense to create tablespaces by applications that are in the PDBs.
You have already most of the system information in the SYSTEM and SYSAUX tablespaces in the CDB, and with current storage technologies, the separation of data files by the application might make the most sense to reduce the management of additional tablespaces; the application can use the PDB application containers for this separation of tablespaces.
Figure 4-2 shows the different tablespaces in CDBs and PDBs.
Figure 4–2. Tablespaces in CDBs and PDBs
We already mentioned briefly CDBs and PDBs; an application container is a pluggable container designed for grouping application objects. It is optional but can store data and metadata for one or more applications.
This allows the PDBs part of the application container to easily share data in central tables. Think of an application container functioning like a CDB within a CDB for grouping common objects for the applications.
In Figure 4-2 you see the separation of the HR PDB and the Inventory PDB, each with a tablespace for those applications, named HRData and INVData.
This is instead of separating them by object types, tables, and indexes.
Even if there is only one PDB, you can separate the application data using HRData and INVData in one PDB.
Here are some reasons to consider creating separate tablespaces for each application using the database:
• Applications may have different availability requirements. Separate tablespaces let you take tablespaces offline for one application without affecting another application.
• Applications may have different backup and recovery requirements. Separate tablespaces let tablespaces be backed up and recovered independently. Separate PDBs could be the solution for this instead of more tablespaces.
• You may have some data that is purely read-only. Separate tablespaces let you put a tablespace that contains only read-only data into read-only mode.
• You may have security settings such as encryption of the tablespace and other tablespaces without encryption.