FLUSH

Purpose

You can use this statement to clear the cache of a specified database.

Syntax

alter_system_flush_stmt:
  ALTER SYSTEM flush_action;

flush_action:
    FLUSH LOCATION CACHE [TENANT [=] tenant_list]
  | FLUSH KVCACHE [TENANT [=] tenant_name] [CACHE [=] cache_name]
  | FLUSH PLAN CACHE [ [SQL_identifier] [database_list] tenant_name_list ] [GLOBAL]

tenant_list:
  tenant_name,tenant_name ...

database_list:
     databases ='database_name, database_name...'

tenant_name_list:
     TENANT = 'tenant_name, tenant_name....'

Parameters

Examples

• Clear the location cache

  obclient> ALTER SYSTEM FLUSH LOCATION CACHE;
  Query OK, 0 rows affected
  

• Clear all KVCaches

  obclient> ALTER SYSTEM FLUSH KVCACHE;
  Query OK, 0 rows affected
  

• Clear the KVCache for MySQL tenants

  obclient> ALTER SYSTEM FLUSH KVCACHE TENANT 'MySQL';
  Query OK, 0 rows affected
  

• Clear the plan cache for all tenants

  obclient> ALTER SYSTEM FLUSH PLAN CACHE;
  Query OK, 0 rows affected
  

• Clear the plan cache for MySQL tenants and Oracle tenants

  obclient> ALTER SYSTEM FLUSH PLAN CACHE TENANT = 'MySQL','Oracle';
  Query OK, 0 rows affected
  

• Clear the specified plan cache in the sys tenant

  obclient> ALTER SYSTEM FLUSH PLAN CACHE sql_id='B601070DFC14CB85FDA3766A69A9E1B3'
        databases='myob1' tenant='tenant1' GLOBAL;
  Query OK, 0 rows affected
  

• Clear the plan cache of a user tenant that has logged on as the DBA

  obclient> ALTER SYSTEM FLUSH PLAN CACHE sql_id='B601070DFC14CB85FDA3766A69A9E1B3'
         databases='myob1' GLOBAL;
  Query OK, 0 rows affected