MySQL 8.4 Reference Manual Including MySQL NDB Cluster 8.4
      The INNODB_SESSION_TEMP_TABLESPACES
      table provides metadata about session temporary tablespaces used
      for internal and user-created temporary tables.
    
      The INNODB_SESSION_TEMP_TABLESPACES
      table has these columns:
    
          ID
        
The process or session ID.
          SPACE
        
The tablespace ID. A range of 400 thousand space IDs is reserved for session temporary tablespaces. Session temporary tablespaces are recreated each time the server is started. Space IDs are not persisted when the server is shut down and may be reused.
          PATH
        
          The tablespace data file path. A session temporary tablespace
          has an ibt file extension.
        
          SIZE
        
The size of the tablespace, in bytes.
          STATE
        
          The state of the tablespace. ACTIVE
          indicates that the tablespace is currently used by a session.
          INACTIVE indicates that the tablespace is
          in the pool of available session temporary tablespaces.
        
          PURPOSE
        
          The purpose of the tablespace. INTRINSIC
          indicates that the tablespace is used for optimized internal
          temporary tables use by the optimizer.
          SLAVE indicates that the tablespace is
          allocated for storing user-created temporary tables on a
          replica. USER indicates that the tablespace
          is used for user-created temporary tables.
          NONE indicates that the tablespace is not
          in use.
        
mysql> SELECT * FROM INFORMATION_SCHEMA.INNODB_SESSION_TEMP_TABLESPACES;
+----+------------+----------------------------+-------+----------+-----------+
| ID | SPACE      | PATH                       | SIZE  | STATE    | PURPOSE   |
+----+------------+----------------------------+-------+----------+-----------+
|  8 | 4294566162 | ./#innodb_temp/temp_10.ibt | 81920 | ACTIVE   | INTRINSIC |
|  8 | 4294566161 | ./#innodb_temp/temp_9.ibt  | 98304 | ACTIVE   | USER      |
|  0 | 4294566153 | ./#innodb_temp/temp_1.ibt  | 81920 | INACTIVE | NONE      |
|  0 | 4294566154 | ./#innodb_temp/temp_2.ibt  | 81920 | INACTIVE | NONE      |
|  0 | 4294566155 | ./#innodb_temp/temp_3.ibt  | 81920 | INACTIVE | NONE      |
|  0 | 4294566156 | ./#innodb_temp/temp_4.ibt  | 81920 | INACTIVE | NONE      |
|  0 | 4294566157 | ./#innodb_temp/temp_5.ibt  | 81920 | INACTIVE | NONE      |
|  0 | 4294566158 | ./#innodb_temp/temp_6.ibt  | 81920 | INACTIVE | NONE      |
|  0 | 4294566159 | ./#innodb_temp/temp_7.ibt  | 81920 | INACTIVE | NONE      |
|  0 | 4294566160 | ./#innodb_temp/temp_8.ibt  | 81920 | INACTIVE | NONE      |
+----+------------+----------------------------+-------+----------+-----------+
          You must have the PROCESS
          privilege to query this table.
        
          Use the INFORMATION_SCHEMA
          COLUMNS table or the
          SHOW COLUMNS statement to view
          additional information about the columns of this table,
          including data types and default values.