ob_bnl_join_cache_size

Description

ob_bnl_join_cache_size specifies the amount of data cached for each Batch Nested Loop Join (BNLJ) operation.

Privilege requirements

• Query variables

  • Global level

    sys tenant and all user tenants can execute the SHOW VARIABLES statement or query the SYS.TENANT_VIRTUAL_GLOBAL_VARIABLE view (Oracle-compatible mode) or the information_schema.GLOBAL_VARIABLES view (MySQL-compatible mode) to view the value of a global system variable.

  • Session level

    sys tenant and all user tenants can execute the SHOW VARIABLES statement or query the SYS.TENANT_VIRTUAL_SESSION_VARIABLE view (Oracle-compatible mode) or the information_schema.SESSION_VARIABLES view (MySQL-compatible mode) to view the value of a session system variable.

• Modify variables

  • Global level

    • sys tenant can modify the value of a global system variable directly.

    • MySQL user tenants must have the SUPER or ALTER SYSTEM privilege to modify the value of a global system variable.

    • Oracle user tenants must have the ALTER SYSTEM privilege to modify the value of a global system variable.

  • Session level

    sys tenant and all user tenants can modify the value of a session system variable directly.

Attributes

Examples

Set the amount of data cached for each Batch Nested Loop Join (BNLJ) operation to 10485760.

• Global level

  obclient> SET GLOBAL ob_bnl_join_cache_size=10485760;
  

• Session level

  obclient> SET ob_bnl_join_cache_size=10485760;