13.1.25 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 13.1.8, “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 13.1.8, “ALTER TABLE Statement”
NDB Cluster formerly supported online DROP INDEX
operations using the ONLINE
and OFFLINE
keywords. These keywords are no longer supported in MySQL NDB Cluster 7.5 and later, and their use causes a syntax error. Instead, MySQL NDB Cluster 7.5 and later support online operations using the same ALGORITHM=INPLACE
syntax used with the standard MySQL Server. See Section 21.5.11, “Online Operations with ALTER TABLE in NDB Cluster”, for more information.