How can I avoid “repair with keycache” in MySQL?

To avoid repair with keycache in MySQL, you need to follow the below syntax −

create table yourNewTableName as (select *from yourOldTableName);
alter table yourNewTableName add index(yourCoumnName);

Let us first create a table −

mysql> create table DemoTable
   (
   StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   StudentFirstName varchar(20),
   StudentLastName varchar(20)
   );
Query OK, 0 rows affected (0.24 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable(StudentFirstName,StudentLastName) values('John','Doe');
Query OK, 1 row affected (0.05 sec)

mysql> insert into DemoTable(StudentFirstName,StudentLastName) values('David','Miller');
Query OK, 1 row affected (0.05 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+-----------+------------------+-----------------+
| StudentId | StudentFirstName | StudentLastName |
+-----------+------------------+-----------------+
| 1         | John             | Doe             |
| 2         | David            | Miller          |
+-----------+------------------+-----------------+
2 rows in set (0.00 sec)

Step 1 − Following is the query to avoid “repair with keycache” in MySQL.

mysql> create table DemoTable as (select *from DemoTable);
Query OK, 2 rows affected (0.34 sec)
Records: 2 Duplicates: 0 Warnings: 0

Step 2 − Now, use alter table

mysql> alter table DemoTable add index(StudentFirstName);
Query OK, 2 rows affected (0.57 sec)
Records: 2 Duplicates: 0 Warnings: 0