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You can use this syntax to add an index and control the kind of index (HASH or BTREE). create index your_index_name on your_table_name(your_column_name) using HASH; or. create index your_index_name on your_table_name(your_column_name) using BTREE;
22 lis 2010 · To add an index to a table without a lock resulting on UPDATE/ INSERT, the following statement format can be used: ALTER TABLE my_table ADD INDEX my_table__idx (my_column), ALGORITHM=INPLACE, LOCK=NONE;
The CREATE INDEX statement is used to create indexes in tables. Indexes are used to retrieve data from the database more quickly than otherwise. The users cannot see the indexes, they are just used to speed up searches/queries.
CREATE INDEX enables you to add indexes to existing tables. CREATE INDEX is mapped to an ALTER TABLE statement to create indexes. See Section 15.1.9, “ALTER TABLE Statement”. CREATE INDEX cannot be used to create a PRIMARY KEY; use ALTER TABLE instead.
6 sty 2013 · You can use a tool like pt-online-schema-change to add the index without blocking your application. The basic logic is as follows: create empty copy of the table with the new index. add triggers to the existing table so that any changes that hit the table will be applied to the copy of the table*.
10.3.1 How MySQL Uses Indexes. Indexes are used to find rows with specific column values quickly. Without an index, MySQL must begin with the first row and then read through the entire table to find the relevant rows. The larger the table, the more this costs. If the table has an index for the columns in question, MySQL can quickly determine ...
To create an index for a column or a list of columns, you specify the index name, the table to which the index belongs, and the column list. For example, to add a new index for the column c4, you use the following statement:
