How to fix database errors

Hi

I have a lot of database errors that I don’t know how to fix. I really need some suggestions or tutorials on how to fix this. Thanks

Errors:

Table_locks_waited 3,231 The number of times that a table lock could not be acquired immediately and a wait was needed. If this is high, and you have performance problems, you should first optimize your queries, and then either split your table or tables or use replication.

Opened_tables 10 k The number of tables that have been opened. If opened tables is big, your table cache value is probably too small.

Select_range_check 1,558 The number of joins without keys that check for key usage after each row. (If this is not 0, you should carefully check the indexes of your tables.)

Select_full_join 5,782 The number of joins that do not use indexes. If this value is not 0, you should carefully check the indexes of your tables.

Handler_read_rnd_next 3,122.51 M The number of requests to read the next row in the data file. This is high if you are doing a lot of table scans. Generally this suggests that your tables are not properly indexed or that your queries are not written to take advantage of the indexes you have.

Slow_queries 88 The number of queries that have taken more than long_query_time seconds.