MySql5.5 SQL optimization slow query log storage

first, MySQL's slow query log opening and storage

1, check whether the SQL records that do not use the index to the slow query log, view the log_queries_not_using_indexes variable;

 like "Log_queries_%"

Results:

If the value of the query is off, it indicates that there is no record, set to on to open the record;

Set = on;

2, check the query time Long_query_time, that is, the query time is greater than this value (in seconds), then log SQL to the slow query log;

 like "Long_query_time"

Results:

set global long_query_time=0.1; /* Set to 100MS */

reopen a Query window , the value of query Long_query_time is modified to 0.1;

Results:

3, check whether to open the slow query log, variable Slow_query_log;

 like "Slow_query_log"

If the value is off, it is not turned on; it should be set to on to open;

Set = on;

4. View the location of the slow query log and view the Slow_query_log_file variable

 like "Slow%"

Results:

5, slow query log storage format:

6, Slow query log analysis tool

(1) Mysqldumpslow use, check the Help

(2) View the top 3 of the path in the slow query log of/home/mysql/data/mysql-slow.log;

Results:

MySql5.5 SQL optimization slow query log storage