Monitoring Analysis of mysql index usage

Mysql index usage monitoring analysis show status like 'handler _ read % ';

Handler_read_first indicates the number of times the index header is read. If the value is very high, it indicates that there are many full index scans. Handler_read_key indicates the number of times an index is used. If we add a new index, we can check whether Handler_read_key has been increased. If so, SQL uses indexes. Www.2cto.com Handler_read_next indicates that the following indexes are read. Generally, range scan occurs. Handler_read_prev indicates the upper column of the index to be read, which usually occurs in order... DESC. Handler_read_rnd indicates reading rows at a fixed position. If the value is very high, it indicates that a large number of result sets are sorted, full table scanning is performed, and no proper KEY is used for associated queries. Handler_read_rnd_next indicates that many table scans are performed and query performance is low. Author gzh0222