Encrypting Temporary Files¶
For InnoDB user-created temporary tables, created in a temporary tablespace
file, use the
Dynamic: Yes Scope: Global Variable Type: Boolean Default Value:
When this variable is set to
ON, the server encrypts the global temporary
tablespace (:file: ibtmp* files) and the session temporary tablespaces
(:file: #innodb_temp/temp_*.ibt files). The variable does not enforce the
encryption of currently open temporary files and does not rebuild the system
temporary tablespace to encrypt data that has already been written.
CREATE TEMPORARY TABLE does not support the
ENCRYPTION clause. The
TABLESPACE clause cannot be set to innodb_temporary.
The global temporary tablespace datafile
ibtmp1 contains the temporary table
undo logs while intrinsic temporary tables and user-created temporary tables
are located in the encrypted session temporary tablespace.
To create new temporary tablespaces unencrypted, the following variables must
be set to
OFF at runtime:
Any existing encrypted user-created temporary files and intrinsic temporary tables remain in an encrypted session.
Temporary tables are only destroyed when the session is disconnected.
The default_table_encryption setting in my.cnf determines if a temporary table is encrypted.
If the innodb_temp_tablespace_encrypt = “OFF” and the
default_table_encryption =”ON”, the user-created temporary tables are
encrypted. The temporary tablespace datafile
ibtmp1, which contains undo
logs, is not encrypted.
innodb_temp_tablespace_encrypt is “ON” for the system tablespace,
InnoDB generates an encryption key and encrypts the system temporary
tablespace. If you reset the encryption to “OFF”, all subsequent pages are
written to an unencrypted tablespace. Any generated keys are not erased to
allow encrypted tables and undo data to be decrypted.
The keyring plugin must be loaded to use the variable. The server generates an error and refuses to create temporary tables if the keyring plugin is not loaded.
For each temporary file, an encryption key has the following attributes:
- Generated locally
- Maintained in memory for the lifetime of the temporary file
- Discarded with the temporary file
Dynamic: No Scope: Global Variable Type: Boolean Default Value:
This variable turns “ON” the encryption of temporary files created by Percona Server for MySQL. The default value is
MySQL Documentation https://dev.mysql.com/doc/refman/8.0/en/create-temporary-table.html