ALTER DATABASE
ALTER DATABASE — change the behavior of the database
Syntax
ALTER DATABASE alter_database_commandWhere alter_database_command can be one or more of the following:
CHANGE ENCRYPTION TYPE <encryption_type>
RUN GARBAGE COLLECTION <target_size>Where encryption_type is NONE, AES128, or AES256, and target_size is the desired amount of used memory (in bytes).
Description
Use ALTER DATABASE to change the operation of the database.
The ALTER DATABASE command affects all SMs and TEs in the database.
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Modifying the Storage Encryption Type
NuoDB supports these encryption types:
| Encryption Type | Description |
|---|---|
|
No storage encryption is enabled on the database |
|
Storage is encrypted with the AES-128 cipher |
|
Storage is encrypted with the AES-256 cipher |
The current storage encryption type of the database can be determined by querying the DISK_ENCRYPTION column in the SYSTEM.NODES table.
If the DISK_ENCRYPTION column contains a percent complete, the SM is in the process of changing the encryption type of its storage.
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Request Garbage Collection
The RUN GARBAGE COLLECTION command is used to request that each SM and TE in the database perform one round of flushing cached data from memory.
This process will stop either when the target_size memory usage is reached, or when all unused data has been released.
This command will not force memory that is in use by the database to be released.
It is best to allow each process to perform its own memory management: users should not need this command under normal circumstances.
| Flushing cached data from memory can significantly impact the performance of the database, until the caches are re-populated. This command may be suggested by NuoDB Support in specific situations. |