content_image/800291.jpg
•For information about dropping stored functions, see Section 13.1.29, “DROP PROCEDURE and DROP FUNCTION Statements” . 

•For information about dropping loadable functions, see Section 13.7.4.2, “DROP FUNCTION Statement for Loadable Functions” . 

## 13.1.27 DROP INDEX Statement 

DROP INDEX index_name  ON tbl_name [ algorithm_option  | lock_option ] ... algorithm_option : ALGORITHM [=] {DEFAULT | INPLACE | COPY} lock_option : LOCK [=] {DEFAULT | NONE | SHARED | EXCLUSIVE} 

DROP INDEX  drops the index named index_name  from the table tbl_name . This statement is mapped to an ALTER TABLE  statement to drop the index. See Section 13.1.9, “ALTER TABLE Statement” . 

To drop a primary key, the index name is always PRIMARY , which must be specified as a quoted identifier because PRIMARY  is a reserved word: 

DROP INDEX ‘PRIMARY‘ ON t; 

Indexes on variable-width columns of NDB  tables are dropped online; that is, without any table copying. The table is not locked against access from other NDB Cluster API nodes, although it is locked against other operations on the same  API node for the duration of the operation. This is done automatically by the server whenever it determines that it is possible to do so; you do not have to use any special SQL syntax or server options to cause it to happen. 

ALGORITHM  and LOCK  clauses may be given to influence the table copying method and level of concurrency for reading and writing the table while its indexes are being modified. They have the same meaning as for the ALTER TABLE  statement. For more information, see Section 13.1.9, “ALTER TABLE Statement” 

MySQL NDB Cluster supports online operations using the same ALGORITHM=INPLACE  syntax supported in the standard MySQL Server. See Section 23.5.11, “Online Operations with ALTER TABLE in NDB Cluster” , for more information. 

## 13.1.28 DROP LOGFILE GROUP Statement 

DROP LOGFILE GROUP logfile_group ENGINE [=] engine_name 

This statement drops the log file group named logfile_group . The log file group must already exist or an error results. (For information on creating log file groups, see Section 13.1.16, “CREATE LOGFILE GROUP Statement” .) 

<img src='content_image/800291.jpg'>

Important 

Before dropping a log file group, you must drop all tablespaces that use that log file group for UNDO  logging. 

The required ENGINE  clause provides the name of the storage engine used by the log file group to be dropped. Currently, the only permitted values for engine_name  are NDB  and NDBCLUSTER . 

DROP LOGFILE GROUP  is useful only with Disk Data storage for NDB Cluster. See Section 23.5.10, “NDB Cluster Disk Data Tables” . 

